about summary refs log tree commit diff stats
diff options
context:
space:
mode:
-rw-r--r--example/expression/access_c.py8
-rw-r--r--example/expression/basic_simplification.py4
-rw-r--r--example/expression/expr_grapher.py8
-rw-r--r--example/expression/expr_reduce.py2
-rw-r--r--example/expression/get_read_write.py8
-rw-r--r--example/expression/simplification_add.py2
-rw-r--r--example/expression/simplification_tools.py10
-rw-r--r--example/expression/solve_condition_stp.py2
-rw-r--r--example/ida/ctype_propagation.py2
-rw-r--r--example/ida/depgraph.py10
-rw-r--r--example/ida/graph_ir.py4
-rw-r--r--example/symbol_exec/depgraph.py10
-rw-r--r--miasm2/analysis/cst_propag.py4
-rw-r--r--miasm2/analysis/data_analysis.py6
-rw-r--r--miasm2/analysis/data_flow.py89
-rw-r--r--miasm2/analysis/depgraph.py10
-rw-r--r--miasm2/analysis/disasm_cb.py4
-rw-r--r--miasm2/arch/aarch64/arch.py2
-rw-r--r--miasm2/arch/aarch64/sem.py50
-rw-r--r--miasm2/arch/arm/arch.py6
-rw-r--r--miasm2/arch/arm/regs.py32
-rw-r--r--miasm2/arch/mips32/ira.py2
-rw-r--r--miasm2/arch/mips32/jit.py14
-rw-r--r--miasm2/arch/mips32/regs.py4
-rw-r--r--miasm2/arch/mips32/sem.py22
-rw-r--r--miasm2/arch/sh4/arch.py6
-rw-r--r--miasm2/arch/x86/regs.py54
-rw-r--r--miasm2/arch/x86/sem.py2
-rw-r--r--miasm2/expression/expression.py5
-rw-r--r--miasm2/expression/simplifications_cond.py6
-rw-r--r--miasm2/ir/ir.py75
-rw-r--r--miasm2/ir/symbexec.py2
-rw-r--r--miasm2/jitter/codegen.py4
-rw-r--r--miasm2/jitter/jitcore_python.py2
-rw-r--r--miasm2/jitter/llvmconvert.py22
-rw-r--r--test/analysis/data_flow.py28
-rw-r--r--test/analysis/depgraph.py72
-rw-r--r--test/core/sembuilder.py12
-rw-r--r--test/expression/expression.py2
-rwxr-xr-xtest/expression/expression_helper.py4
-rw-r--r--test/expression/simplifications.py28
-rw-r--r--test/ir/ir.py4
-rwxr-xr-xtest/ir/symbexec.py6
43 files changed, 346 insertions, 303 deletions
diff --git a/example/expression/access_c.py b/example/expression/access_c.py
index f285eb55..de158730 100644
--- a/example/expression/access_c.py
+++ b/example/expression/access_c.py
@@ -60,15 +60,15 @@ def find_call(ira):
 
     for irb in ira.blocks.values():
         out = set()
-        if len(irb.irs) < 2:
+        if len(irb) < 2:
             continue
-        assignblk = irb.irs[-2]
+        assignblk = irb[-2]
         for src in assignblk.itervalues():
             if not isinstance(src, ExprOp):
                 continue
             if not src.op.startswith('call_func'):
                 continue
-            out.add((irb, len(irb.irs) - 2))
+            out.add((irb, len(irb) - 2))
         if len(out) != 1:
             continue
         irb, index = out.pop()
@@ -98,7 +98,7 @@ def get_funcs_arg0(ctx, ira, lbl_head):
     element = ira.arch.regs.RSI
 
     for irb, index in find_call(ira):
-        instr = irb.irs[index].instr
+        instr = irb[index].instr
         print 'Analysing references from:', hex(instr.offset), instr
         g_list = g_dep.get(irb.label, set([element]), index, set([lbl_head]))
         for dep in g_list:
diff --git a/example/expression/basic_simplification.py b/example/expression/basic_simplification.py
index ef904686..eefdc765 100644
--- a/example/expression/basic_simplification.py
+++ b/example/expression/basic_simplification.py
@@ -6,8 +6,8 @@ Simple expression simplification demo
 """
 
 
-a = ExprId('eax')
-b = ExprId('ebx')
+a = ExprId('eax', 32)
+b = ExprId('ebx', 32)
 
 exprs = [a + b - a,
          ExprInt(0x12, 32) + ExprInt(0x30, 32) - a,
diff --git a/example/expression/expr_grapher.py b/example/expression/expr_grapher.py
index 0de2142b..9bf6cd84 100644
--- a/example/expression/expr_grapher.py
+++ b/example/expression/expr_grapher.py
@@ -2,10 +2,10 @@ from miasm2.expression.expression import *
 
 print "Simple Expression grapher demo"
 
-a = ExprId("A")
-b = ExprId("B")
-c = ExprId("C")
-d = ExprId("D")
+a = ExprId("A", 32)
+b = ExprId("B", 32)
+c = ExprId("C", 32)
+d = ExprId("D", 32)
 m = ExprMem(a + b + c + a)
 
 e1 = ExprCompose(a + b - (c * a) / m | b, a + m)
diff --git a/example/expression/expr_reduce.py b/example/expression/expr_reduce.py
index bb94ceb9..7c6e0c4c 100644
--- a/example/expression/expr_reduce.py
+++ b/example/expression/expr_reduce.py
@@ -75,7 +75,7 @@ class StructLookup(ExprReducer):
 def test():
     struct_lookup = StructLookup()
 
-    ptr = ExprId('ECX')
+    ptr = ExprId('ECX', 32)
     int4 = ExprInt(4, 32)
     tests = [
         (ptr, StructLookup.FIELD_A_PTR),
diff --git a/example/expression/get_read_write.py b/example/expression/get_read_write.py
index f4dde4b5..b4a0773b 100644
--- a/example/expression/get_read_write.py
+++ b/example/expression/get_read_write.py
@@ -16,10 +16,10 @@ l.offset, l.l = 0, 15
 ir_arch.add_instr(l)
 
 print '*' * 80
-for lbl, b in ir_arch.blocks.items():
-    print b
-    for irs in b.irs:
-        o_r, o_w = get_rw(irs)
+for lbl, irblock in ir_arch.blocks.items():
+    print irblock
+    for assignblk in irblock:
+        o_r, o_w = get_rw(assignblk)
         print 'read:   ', [str(x) for x in o_r]
         print 'written:', [str(x) for x in o_w]
         print
diff --git a/example/expression/simplification_add.py b/example/expression/simplification_add.py
index 41720f3a..621d1139 100644
--- a/example/expression/simplification_add.py
+++ b/example/expression/simplification_add.py
@@ -30,7 +30,7 @@ def simp_add_mul(expr_simp, expr):
         # Do not simplify
         return expr
 
-a = m2_expr.ExprId('a')
+a = m2_expr.ExprId('a', 32)
 base_expr = a + a + a
 print "Without adding the simplification:"
 print "\t%s = %s" % (base_expr, expr_simp(base_expr))
diff --git a/example/expression/simplification_tools.py b/example/expression/simplification_tools.py
index 258b5ce4..1fb95a80 100644
--- a/example/expression/simplification_tools.py
+++ b/example/expression/simplification_tools.py
@@ -7,11 +7,11 @@ Expression simplification demo.
 """
 
 
-a = ExprId('a')
-b = ExprId('b')
-c = ExprId('c')
-d = ExprId('d')
-e = ExprId('e')
+a = ExprId('a', 32)
+b = ExprId('b', 32)
+c = ExprId('c', 32)
+d = ExprId('d', 32)
+e = ExprId('e', 32)
 
 m = ExprMem(a)
 s = a[:8]
diff --git a/example/expression/solve_condition_stp.py b/example/expression/solve_condition_stp.py
index b3ee6938..24d2dd50 100644
--- a/example/expression/solve_condition_stp.py
+++ b/example/expression/solve_condition_stp.py
@@ -109,7 +109,7 @@ if __name__ == '__main__':
 
     argc = ExprId('argc', 32)
     argv = ExprId('argv', 32)
-    ret_addr = ExprId('ret_addr')
+    ret_addr = ExprId('ret_addr', 32)
     reg_and_id[argc.name] = argc
     reg_and_id[argv.name] = argv
     reg_and_id[ret_addr.name] = ret_addr
diff --git a/example/ida/ctype_propagation.py b/example/ida/ctype_propagation.py
index 8c64c6d2..54b23516 100644
--- a/example/ida/ctype_propagation.py
+++ b/example/ida/ctype_propagation.py
@@ -114,7 +114,7 @@ class SymbExecCTypeFix(SymbExecCType):
         """
 
         offset2cmt = {}
-        for index, assignblk in enumerate(irb.irs):
+        for index, assignblk in enumerate(irb):
             if set(assignblk) == set([self.ir_arch.IRDst, self.ir_arch.pc]):
                 # Don't display on jxx
                 continue
diff --git a/example/ida/depgraph.py b/example/ida/depgraph.py
index 915f14bc..5342313a 100644
--- a/example/ida/depgraph.py
+++ b/example/ida/depgraph.py
@@ -34,7 +34,7 @@ class depGraphSettingsForm(ida_kernwin.Form):
                 cur_block = block
         assert cur_block is not None
         line_nb = None
-        for line_nb, assignblk in enumerate(cur_block.irs):
+        for line_nb, assignblk in enumerate(cur_block):
             if assignblk.instr.offset == self.address:
                 break
         assert line_nb is not None
@@ -110,13 +110,13 @@ Method to use:
         elif mode == 1:
             return value + 1
         else:
-            return len(self.ira.blocks[self.label].irs)
+            return len(self.ira.blocks[self.label])
 
     @property
     def elements(self):
         value = self.cbReg.value
         if value in self.stk_args:
-            line = self.ira.blocks[self.label].irs[self.line_nb].instr
+            line = self.ira.blocks[self.label][self.line_nb].instr
             arg_num = self.stk_args[value]
             stk_high = m2_expr.ExprInt(idc.GetSpd(line.offset), ir_arch.sp.size)
             stk_off = m2_expr.ExprInt(self.ira.sp.size/8 * arg_num, ir_arch.sp.size)
@@ -174,7 +174,7 @@ def treat_element():
 
     for node in graph.relevant_nodes:
         try:
-            offset = ir_arch.blocks[node.label].irs[node.line_nb].instr.offset
+            offset = ir_arch.blocks[node.label][node.line_nb].instr.offset
         except IndexError:
             print "Unable to highlight %s" % node
             continue
@@ -229,7 +229,7 @@ def launch_depgraph():
     for irb in ir_arch.blocks.values():
         irs = []
         fix_stack = irb.label.offset is not None and settings.unalias_stack
-        for assignblk in irb.irs:
+        for assignblk in irb:
             if fix_stack:
                 stk_high = m2_expr.ExprInt(idc.GetSpd(assignblk.instr.offset), ir_arch.sp.size)
                 fix_dct = {ir_arch.sp: mn.regs.regs_init[ir_arch.sp] + stk_high}
diff --git a/example/ida/graph_ir.py b/example/ida/graph_ir.py
index 8d9dea4f..7e303aac 100644
--- a/example/ida/graph_ir.py
+++ b/example/ida/graph_ir.py
@@ -40,7 +40,7 @@ def color_irblock(irblock, ir_arch):
     out = []
     lbl = idaapi.COLSTR(str(irblock.label), idaapi.SCOLOR_INSN)
     out.append(lbl)
-    for assignblk in irblock.irs:
+    for assignblk in irblock:
         for dst, src in sorted(assignblk.iteritems()):
             dst_f = expr2colorstr(ir_arch.arch.regs.all_regs_ids, dst)
             src_f = expr2colorstr(ir_arch.arch.regs.all_regs_ids, src)
@@ -148,7 +148,7 @@ def build_graph(verbose=False, simplify=False):
 
     for irb in ir_arch.blocks.itervalues():
         irs = []
-        for assignblk in irb.irs:
+        for assignblk in irb:
             new_assignblk = {
                 expr_simp(dst): expr_simp(src)
                 for dst, src in assignblk.iteritems()
diff --git a/example/symbol_exec/depgraph.py b/example/symbol_exec/depgraph.py
index c1d6174d..b8d838ae 100644
--- a/example/symbol_exec/depgraph.py
+++ b/example/symbol_exec/depgraph.py
@@ -55,8 +55,8 @@ if args.rename_args:
     if arch == "x86_32":
         # StdCall example
         for i in xrange(4):
-            e_mem = ExprMem(ExprId("ESP_init") + ExprInt(4 * (i + 1), 32), 32)
-            init_ctx[e_mem] = ExprId("arg%d" % i)
+            e_mem = ExprMem(ExprId("ESP_init", 32) + ExprInt(4 * (i + 1), 32), 32)
+            init_ctx[e_mem] = ExprId("arg%d" % i, 32)
 
 # Disassemble the targeted function
 blocks = mdis.dis_multiblock(int(args.func_addr, 0))
@@ -74,14 +74,14 @@ dg = DependencyGraph(ir_arch, implicit=args.implicit,
 # Build information
 target_addr = int(args.target_addr, 0)
 current_block = list(ir_arch.getby_offset(target_addr))[0]
-line_nb = 0
-for line_nb, assignblk in enumerate(current_block.irs):
+assignblk_index = 0
+for assignblk_index, assignblk in enumerate(current_block):
     if assignblk.instr.offset == target_addr:
         break
 
 # Enumerate solutions
 json_solutions = []
-for sol_nb, sol in enumerate(dg.get(current_block.label, elements, line_nb, set())):
+for sol_nb, sol in enumerate(dg.get(current_block.label, elements, assignblk_index, set())):
     fname = "sol_%d.dot" % sol_nb
     with open(fname, "w") as fdesc:
             fdesc.write(sol.graph.dot())
diff --git a/miasm2/analysis/cst_propag.py b/miasm2/analysis/cst_propag.py
index 2a439ccc..7946a496 100644
--- a/miasm2/analysis/cst_propag.py
+++ b/miasm2/analysis/cst_propag.py
@@ -73,7 +73,7 @@ class SymbExecStateFix(SymbolicExecutionEngine):
         self.cst_propag_link = cst_propag_link
 
     def propag_expr_cst(self, expr):
-        """Propagate consttant expressions in @expr
+        """Propagate constant expressions in @expr
         @expr: Expression to update"""
         elements = expr.get_r(mem_read=True)
         to_propag = {}
@@ -93,7 +93,7 @@ class SymbExecStateFix(SymbolicExecutionEngine):
         @step: display intermediate steps
         """
         assignblks = []
-        for index, assignblk in enumerate(irb.irs):
+        for index, assignblk in enumerate(irb):
             new_assignblk = {}
             links = {}
             for dst, src in assignblk.iteritems():
diff --git a/miasm2/analysis/data_analysis.py b/miasm2/analysis/data_analysis.py
index b3e15ca6..130d45a4 100644
--- a/miasm2/analysis/data_analysis.py
+++ b/miasm2/analysis/data_analysis.py
@@ -14,7 +14,7 @@ def intra_block_flow_raw(ir_arch, flow_graph, irb, in_nodes, out_nodes):
     Create data flow for an irbloc using raw IR expressions
     """
     current_nodes = {}
-    for i, assignblk in enumerate(irb.irs):
+    for i, assignblk in enumerate(irb):
         dict_rw = assignblk.get_rw(cst_read=True)
         if irb.label.offset == 0x13:
             print irb.label
@@ -85,7 +85,7 @@ def intra_block_flow_symbexec(ir_arch, flow_graph, irb, in_nodes, out_nodes):
             continue
         read_values = v.get_r(cst_read=True)
         # print n_w, v, [str(x) for x in read_values]
-        node_n_w = get_node_name(irb.label, len(irb.irs), n_w)
+        node_n_w = get_node_name(irb.label, len(irb), n_w)
 
         for n_r in read_values:
             if n_r in current_nodes:
@@ -171,7 +171,7 @@ def create_implicit_flow(ir_arch, flow_graph, irb_in_nodes, irb_out_ndes):
                 # print "###", irb_son
                 # print "###", 'IN', [str(x) for x in irb_son.in_nodes]
 
-                node_n_w = irb.label, len(irb.irs), n_r
+                node_n_w = irb.label, len(irb), n_r
                 irb_out_nodes[irb.label][n_r] = node_n_w
                 if not n_r in irb_in_nodes[irb.label]:
                     irb_in_nodes[irb.label][n_r] = irb.label, 0, n_r
diff --git a/miasm2/analysis/data_flow.py b/miasm2/analysis/data_flow.py
index 67768264..d9f61c56 100644
--- a/miasm2/analysis/data_flow.py
+++ b/miasm2/analysis/data_flow.py
@@ -6,7 +6,7 @@ from miasm2.ir.ir import AssignBlock, IRBlock
 
 class ReachingDefinitions(dict):
     """
-    Computes for each instruction the set of reaching definitions.
+    Computes for each assignblock the set of reaching definitions.
     Example:
     IR block:
     lbl0:
@@ -26,7 +26,7 @@ class ReachingDefinitions(dict):
     IBM Thomas J. Watson Research Division,  Algorithm MK
 
     This class is usable as a dictionnary whose struture is
-    { (block, instr_index): { lvalue: set((block, instr_index)) } }
+    { (block, index): { lvalue: set((block, index)) } }
     """
 
     ir_a = None
@@ -36,12 +36,12 @@ class ReachingDefinitions(dict):
         self.ir_a = ir_a
         self.compute()
 
-    def get_definitions(self, block_lbl, instruction):
-        """Returns the dict { lvalue: set((def_block_lbl, def_instr_index)) }
-        associated with self.ir_a.@block.irs[@instruction]
+    def get_definitions(self, block_lbl, assignblk_index):
+        """Returns the dict { lvalue: set((def_block_lbl, def_index)) }
+        associated with self.ir_a.@block.assignblks[@assignblk_index]
         or {} if it is not yet computed
         """
-        return self.get((block_lbl, instruction), {})
+        return self.get((block_lbl, assignblk_index), {})
 
     def compute(self):
         """This is the main fixpoint"""
@@ -54,12 +54,12 @@ class ReachingDefinitions(dict):
     def process_block(self, block):
         """
         Fetch reach definitions from predecessors and propagate it to
-        the instruction in block @block.
+        the assignblk in block @block.
         """
         predecessor_state = {}
         for pred_lbl in self.ir_a.graph.predecessors(block.label):
             pred = self.ir_a.blocks[pred_lbl]
-            for lval, definitions in self.get_definitions(pred_lbl, len(pred.irs)).iteritems():
+            for lval, definitions in self.get_definitions(pred_lbl, len(pred)).iteritems():
                 predecessor_state.setdefault(lval, set()).update(definitions)
 
         modified = self.get((block.label, 0)) != predecessor_state
@@ -67,33 +67,33 @@ class ReachingDefinitions(dict):
             return False
         self[(block.label, 0)] = predecessor_state
 
-        for instr_index in xrange(len(block.irs)):
-            modified |= self.process_instruction(block, instr_index)
+        for index in xrange(len(block)):
+            modified |= self.process_assignblock(block, index)
         return modified
 
-    def process_instruction(self, block, instr_index):
+    def process_assignblock(self, block, assignblk_index):
         """
         Updates the reach definitions with values defined at
-        instruction @instr_index in block @block.
-        NB: the effect of instruction @instr_index in stored at index
-        (@block, @instr_index + 1).
+        assignblock @assignblk_index in block @block.
+        NB: the effect of assignblock @assignblk_index in stored at index
+        (@block, @assignblk_index + 1).
         """
 
-        instr = block.irs[instr_index]
-        defs = self.get_definitions(block.label, instr_index).copy()
-        for lval in instr:
-            defs.update({lval: set([(block.label, instr_index)])})
+        assignblk = block[assignblk_index]
+        defs = self.get_definitions(block.label, assignblk_index).copy()
+        for lval in assignblk:
+            defs.update({lval: set([(block.label, assignblk_index)])})
 
-        modified = self.get((block.label, instr_index + 1)) != defs
+        modified = self.get((block.label, assignblk_index + 1)) != defs
         if modified:
-            self[(block.label, instr_index + 1)] = defs
+            self[(block.label, assignblk_index + 1)] = defs
 
         return modified
 
 ATTR_DEP = {"color" : "black",
             "_type" : "data"}
 
-InstrNode = namedtuple('InstructionNode', ['label', 'index', 'var'])
+AssignblkNode = namedtuple('AssignblkNode', ['label', 'index', 'var'])
 
 class DiGraphDefUse(DiGraph):
     """Representation of a Use-Definition graph as defined by
@@ -148,18 +148,18 @@ class DiGraphDefUse(DiGraph):
                                         deref_mem=deref_mem)
 
     def _compute_def_use_block(self, block, reaching_defs, deref_mem=False):
-        for ind, instr in enumerate(block.irs):
-            instruction_reaching_defs = reaching_defs.get_definitions(block.label, ind)
-            for lval, expr in instr.iteritems():
-                self.add_node(InstrNode(block.label, ind, lval))
+        for index, assignblk in enumerate(block):
+            assignblk_reaching_defs = reaching_defs.get_definitions(block.label, index)
+            for lval, expr in assignblk.iteritems():
+                self.add_node(AssignblkNode(block.label, index, lval))
 
                 read_vars = expr.get_r(mem_read=deref_mem)
                 if deref_mem and lval.is_mem():
                     read_vars.update(lval.arg.get_r(mem_read=deref_mem))
                 for read_var in read_vars:
-                    for reach in instruction_reaching_defs.get(read_var, set()):
-                        self.add_data_edge(InstrNode(reach[0], reach[1], read_var),
-                                           InstrNode(block.label, ind, lval))
+                    for reach in assignblk_reaching_defs.get(read_var, set()):
+                        self.add_data_edge(AssignblkNode(reach[0], reach[1], read_var),
+                                           AssignblkNode(block.label, index, lval))
 
     def del_edge(self, src, dst):
         super(DiGraphDefUse, self).del_edge(src, dst)
@@ -178,25 +178,25 @@ class DiGraphDefUse(DiGraph):
         self.add_uniq_labeled_edge(src, dst, ATTR_DEP)
 
     def node2lines(self, node):
-        lbl, ind, reg = node
-        yield self.DotCellDescription(text="%s (%s)" % (lbl, ind),
+        lbl, index, reg = node
+        yield self.DotCellDescription(text="%s (%s)" % (lbl, index),
                                       attr={'align': 'center',
                                             'colspan': 2,
                                             'bgcolor': 'grey'})
-        src = self._blocks[lbl].irs[ind][reg]
+        src = self._blocks[lbl][index][reg]
         line = "%s = %s" % (reg, src)
         yield self.DotCellDescription(text=line, attr={})
         yield self.DotCellDescription(text="", attr={})
 
 
-def dead_simp_useful_instrs(defuse, reaching_defs):
+def dead_simp_useful_assignblks(defuse, reaching_defs):
     """Mark useful statements using previous reach analysis and defuse
 
     Source : Kennedy, K. (1979). A survey of data flow analysis techniques.
     IBM Thomas J. Watson Research Division,  Algorithm MK
 
-    Return a set of triplets (block, instruction number, instruction) of
-    useful instructions
+    Return a set of triplets (block, assignblk number, lvalue) of
+    useful definitions
     PRE: compute_reach(self)
 
     """
@@ -215,20 +215,20 @@ def dead_simp_useful_instrs(defuse, reaching_defs):
         # Block has a nonexistant successor or is a leaf
         if keep_all_definitions or (len(successors) == 0):
             valid_definitions = reaching_defs.get_definitions(block_lbl,
-                                                              len(block.irs))
+                                                              len(block))
             for lval, definitions in valid_definitions.iteritems():
                 if (lval in ir_a.get_out_regs(block)
                     or keep_all_definitions):
                     for definition in definitions:
-                        useful.add(InstrNode(definition[0], definition[1], lval))
+                        useful.add(AssignblkNode(definition[0], definition[1], lval))
 
         # Force keeping of specific cases
-        for instr_index, instr in enumerate(block.irs):
-            for lval, rval in instr.iteritems():
+        for index, assignblk in enumerate(block):
+            for lval, rval in assignblk.iteritems():
                 if (lval.is_mem()
                     or ir_a.IRDst == lval
                     or rval.is_function_call()):
-                    useful.add(InstrNode(block_lbl, instr_index, lval))
+                    useful.add(AssignblkNode(block_lbl, index, lval))
 
     # Useful nodes dependencies
     for node in useful:
@@ -237,22 +237,27 @@ def dead_simp_useful_instrs(defuse, reaching_defs):
 
 def dead_simp(ir_a):
     """
+    Remove useless affectations.
+
     This function is used to analyse relation of a * complete function *
     This means the blocks under study represent a solid full function graph.
 
     Source : Kennedy, K. (1979). A survey of data flow analysis techniques.
     IBM Thomas J. Watson Research Division, page 43
+
+    @ir_a: IntermediateRepresentation instance
     """
+
     modified = False
     reaching_defs = ReachingDefinitions(ir_a)
     defuse = DiGraphDefUse(reaching_defs, deref_mem=True)
-    useful = set(dead_simp_useful_instrs(defuse, reaching_defs))
+    useful = set(dead_simp_useful_assignblks(defuse, reaching_defs))
     for block in ir_a.blocks.itervalues():
         irs = []
-        for idx, assignblk in enumerate(block.irs):
+        for idx, assignblk in enumerate(block):
             new_assignblk = dict(assignblk)
             for lval in assignblk:
-                if InstrNode(block.label, idx, lval) not in useful:
+                if AssignblkNode(block.label, idx, lval) not in useful:
                     del new_assignblk[lval]
                     modified = True
             irs.append(AssignBlock(new_assignblk, assignblk.instr))
diff --git a/miasm2/analysis/depgraph.py b/miasm2/analysis/depgraph.py
index d1ac13c8..bd4bfa7e 100644
--- a/miasm2/analysis/depgraph.py
+++ b/miasm2/analysis/depgraph.py
@@ -265,9 +265,9 @@ class DependencyResult(DependencyState):
                 break
             assignmnts = {}
             for element in elements:
-                if element in irb.irs[line_nb]:
+                if element in irb[line_nb]:
                     # constants, label, ... are not in destination
-                    assignmnts[element] = irb.irs[line_nb][element]
+                    assignmnts[element] = irb[line_nb][element]
             assignblks.append(AssignBlock(assignmnts))
 
         return IRBlock(irb.label, assignblks)
@@ -294,7 +294,7 @@ class DependencyResult(DependencyState):
             else:
                 line_nb = None
             assignblks += self.irblock_slice(self._ira.blocks[label],
-                                             line_nb).irs
+                                             line_nb).assignblks
 
         # Eval the block
         temp_label = AsmLabel("Temp")
@@ -581,9 +581,9 @@ class DependencyGraph(object):
         @state: instance of DependencyState"""
 
         irb = self._ira.blocks[state.label]
-        line_nb = len(irb.irs) if state.line_nb is None else state.line_nb
+        line_nb = len(irb) if state.line_nb is None else state.line_nb
 
-        for cur_line_nb, assignblk in reversed(list(enumerate(irb.irs[:line_nb]))):
+        for cur_line_nb, assignblk in reversed(list(enumerate(irb[:line_nb]))):
             self._track_exprs(state, assignblk, cur_line_nb)
 
     def get(self, label, elements, line_nb, heads):
diff --git a/miasm2/analysis/disasm_cb.py b/miasm2/analysis/disasm_cb.py
index 9a75603f..e759e313 100644
--- a/miasm2/analysis/disasm_cb.py
+++ b/miasm2/analysis/disasm_cb.py
@@ -39,7 +39,7 @@ def arm_guess_subcall(
         # print irblock
         pc_val = None
         lr_val = None
-        for exprs in irblock.irs:
+        for exprs in irblock:
             for e in exprs:
                 if e.dst == ir_arch.pc:
                     pc_val = e.src
@@ -84,7 +84,7 @@ def arm_guess_jump_table(
         # print irblock
         pc_val = None
         # lr_val = None
-        for exprs in irblock.irs:
+        for exprs in irblock:
             for e in exprs:
                 if e.dst == ir_arch.pc:
                     pc_val = e.src
diff --git a/miasm2/arch/aarch64/arch.py b/miasm2/arch/aarch64/arch.py
index 7af1953a..2712e60a 100644
--- a/miasm2/arch/aarch64/arch.py
+++ b/miasm2/arch/aarch64/arch.py
@@ -219,7 +219,7 @@ simdregs_h_zero = (simd32_info.parser |
 
 def ast_id2expr(t):
     if not t in mn_aarch64.regs.all_regs_ids_byname:
-        r = m2_expr.ExprId(AsmLabel(t))
+        r = m2_expr.ExprId(AsmLabel(t), 32)
     else:
         r = mn_aarch64.regs.all_regs_ids_byname[t]
     return r
diff --git a/miasm2/arch/aarch64/sem.py b/miasm2/arch/aarch64/sem.py
index a1c6b41d..a575c819 100644
--- a/miasm2/arch/aarch64/sem.py
+++ b/miasm2/arch/aarch64/sem.py
@@ -417,26 +417,47 @@ def ldr(ir, instr, arg1, arg2):
     return e, []
 
 
-def ldrb(ir, instr, arg1, arg2):
+def ldr_size(ir, instr, arg1, arg2, size):
     e = []
     addr, updt = get_mem_access(arg2)
     e.append(
-        m2_expr.ExprAff(arg1, m2_expr.ExprMem(addr, 8).zeroExtend(arg1.size)))
+        m2_expr.ExprAff(arg1, m2_expr.ExprMem(addr, size).zeroExtend(arg1.size)))
     if updt:
         e.append(updt)
     return e, []
 
 
+def ldrb(ir, instr, arg1, arg2):
+    return ldr_size(ir, instr, arg1, arg2, 8)
+
+
 def ldrh(ir, instr, arg1, arg2):
+    return ldr_size(ir, instr, arg1, arg2, 16)
+
+
+def ldrs_size(ir, instr, arg1, arg2, size):
     e = []
     addr, updt = get_mem_access(arg2)
     e.append(
-        m2_expr.ExprAff(arg1, m2_expr.ExprMem(addr, 16).zeroExtend(arg1.size)))
+        m2_expr.ExprAff(arg1, m2_expr.ExprMem(addr, size).signExtend(arg1.size)))
     if updt:
         e.append(updt)
     return e, []
 
 
+def ldrsb(ir, instr, arg1, arg2):
+    return ldrs_size(ir, instr, arg1, arg2, 8)
+
+
+def ldrsh(ir, instr, arg1, arg2):
+    return ldrs_size(ir, instr, arg1, arg2, 16)
+
+
+def ldrsw(ir, instr, arg1, arg2):
+    return ldrs_size(ir, instr, arg1, arg2, 32)
+
+
+
 def l_str(ir, instr, arg1, arg2):
     e = []
     addr, updt = get_mem_access(arg2)
@@ -486,16 +507,6 @@ def ldp(ir, instr, arg1, arg2, arg3):
     return e, []
 
 
-def ldrsw(ir, instr, arg1, arg2):
-    e = []
-    addr, updt = get_mem_access(arg2)
-    e.append(
-        m2_expr.ExprAff(arg1, m2_expr.ExprMem(addr, 32).signExtend(arg1.size)))
-    if updt:
-        e.append(updt)
-    return e, []
-
-
 def sbfm(ir, instr, arg1, arg2, arg3, arg4):
     e = []
     rim, sim = int(arg3.arg), int(arg4) + 1
@@ -745,7 +756,14 @@ mnemo_func.update({
 
     'ldur': ldr,
     'ldurb': ldrb,
+    'ldursb': ldrsb,
     'ldurh': ldrh,
+    'ldursh': ldrsh,
+    'ldursw': ldrsw,
+
+    'ldrsb': ldrsb,
+    'ldrsh': ldrsh,
+    'ldrsw': ldrsw,
 
     'str': l_str,
     'strb': strb,
@@ -755,8 +773,6 @@ mnemo_func.update({
     'sturb': strb,
     'sturh': strh,
 
-    'ldrsw': ldrsw,
-
 
     'bfm': bfm,
     'sbfm': sbfm,
@@ -811,7 +827,7 @@ class ir_aarch64l(IntermediateRepresentation):
 
     def irbloc_fix_regs_for_mode(self, irblock, mode=64):
         irs = []
-        for assignblk in irblock.irs:
+        for assignblk in irblock:
             new_assignblk = dict(assignblk)
             for dst, src in assignblk.iteritems():
                 del(new_assignblk[dst])
@@ -854,7 +870,7 @@ class ir_aarch64l(IntermediateRepresentation):
         new_irblocks = []
         for irblock in extra_ir:
             irs = []
-            for assignblk in irblock.irs:
+            for assignblk in irblock:
                 new_dsts = {dst:src for dst, src in assignblk.iteritems()
                                 if dst not in regs_to_fix}
                 irs.append(AssignBlock(new_dsts, assignblk.instr))
diff --git a/miasm2/arch/arm/arch.py b/miasm2/arch/arm/arch.py
index c74d10a8..5e4b02f9 100644
--- a/miasm2/arch/arm/arch.py
+++ b/miasm2/arch/arm/arch.py
@@ -18,7 +18,7 @@ log.addHandler(console_handler)
 log.setLevel(logging.DEBUG)
 
 # arm regs ##############
-reg_dum = ExprId('DumReg')
+reg_dum = ExprId('DumReg', 32)
 
 gen_reg('PC', globals())
 
@@ -66,13 +66,13 @@ spsr_regs = reg_info(spsr_regs_str, spsr_regs_expr)
 
 # CP
 cpregs_str = ['c%d' % r for r in xrange(0x10)]
-cpregs_expr = [ExprId(x) for x in cpregs_str]
+cpregs_expr = [ExprId(x, 32) for x in cpregs_str]
 
 cp_regs = reg_info(cpregs_str, cpregs_expr)
 
 # P
 pregs_str = ['p%d' % r for r in xrange(0x10)]
-pregs_expr = [ExprId(x) for x in pregs_str]
+pregs_expr = [ExprId(x, 32) for x in pregs_str]
 
 p_regs = reg_info(pregs_str, pregs_expr)
 
diff --git a/miasm2/arch/arm/regs.py b/miasm2/arch/arm/regs.py
index 400c6080..8587d7c2 100644
--- a/miasm2/arch/arm/regs.py
+++ b/miasm2/arch/arm/regs.py
@@ -29,22 +29,22 @@ SP = regs32_expr[13]
 LR = regs32_expr[14]
 PC = regs32_expr[15]
 
-R0_init = ExprId("R0_init")
-R1_init = ExprId("R1_init")
-R2_init = ExprId("R2_init")
-R3_init = ExprId("R3_init")
-R4_init = ExprId("R4_init")
-R5_init = ExprId("R5_init")
-R6_init = ExprId("R6_init")
-R7_init = ExprId("R7_init")
-R8_init = ExprId("R8_init")
-R9_init = ExprId("R9_init")
-R10_init = ExprId("R10_init")
-R11_init = ExprId("R11_init")
-R12_init = ExprId("R12_init")
-SP_init = ExprId("SP_init")
-LR_init = ExprId("LR_init")
-PC_init = ExprId("PC_init")
+R0_init = ExprId("R0_init", 32)
+R1_init = ExprId("R1_init", 32)
+R2_init = ExprId("R2_init", 32)
+R3_init = ExprId("R3_init", 32)
+R4_init = ExprId("R4_init", 32)
+R5_init = ExprId("R5_init", 32)
+R6_init = ExprId("R6_init", 32)
+R7_init = ExprId("R7_init", 32)
+R8_init = ExprId("R8_init", 32)
+R9_init = ExprId("R9_init", 32)
+R10_init = ExprId("R10_init", 32)
+R11_init = ExprId("R11_init", 32)
+R12_init = ExprId("R12_init", 32)
+SP_init = ExprId("SP_init", 32)
+LR_init = ExprId("LR_init", 32)
+PC_init = ExprId("PC_init", 32)
 
 
 reg_zf = 'zf'
diff --git a/miasm2/arch/mips32/ira.py b/miasm2/arch/mips32/ira.py
index f1e21a41..7aefad32 100644
--- a/miasm2/arch/mips32/ira.py
+++ b/miasm2/arch/mips32/ira.py
@@ -21,7 +21,7 @@ class ir_a_mips32l(ir_mips32l, ira):
         for irb in ir_blocks:
             pc_val = None
             lr_val = None
-            for assignblk in irb.irs:
+            for assignblk in irb:
                 pc_val = assignblk.get(self.arch.regs.PC, pc_val)
                 lr_val = assignblk.get(self.arch.regs.RA, lr_val)
 
diff --git a/miasm2/arch/mips32/jit.py b/miasm2/arch/mips32/jit.py
index 493da595..1d2ec483 100644
--- a/miasm2/arch/mips32/jit.py
+++ b/miasm2/arch/mips32/jit.py
@@ -35,19 +35,19 @@ class mipsCGen(CGen):
 
     def __init__(self, ir_arch):
         super(mipsCGen, self).__init__(ir_arch)
-        self.delay_slot_dst = m2_expr.ExprId("branch_dst_irdst")
-        self.delay_slot_set = m2_expr.ExprId("branch_dst_set")
+        self.delay_slot_dst = m2_expr.ExprId("branch_dst_irdst", 32)
+        self.delay_slot_set = m2_expr.ExprId("branch_dst_set", 32)
 
     def block2assignblks(self, block):
         irblocks_list = super(mipsCGen, self).block2assignblks(block)
         for irblocks in irblocks_list:
             for blk_idx, irblock in enumerate(irblocks):
-                has_breakflow = any(assignblock.instr.breakflow() for assignblock in irblock.irs)
+                has_breakflow = any(assignblock.instr.breakflow() for assignblock in irblock)
                 if not has_breakflow:
                     continue
 
                 irs = []
-                for assignblock in irblock.irs:
+                for assignblock in irblock:
                     if self.ir_arch.pc not in assignblock:
                         irs.append(AssignBlock(assignments, assignblock.instr))
                         continue
@@ -58,7 +58,7 @@ class mipsCGen(CGen):
                     assignments[self.delay_slot_set] = m2_expr.ExprInt(1, 32)
                     # Replace IRDst with next instruction
                     assignments[self.ir_arch.IRDst] = m2_expr.ExprId(
-                        self.ir_arch.get_next_instr(assignblock.instr))
+                        self.ir_arch.get_next_instr(assignblock.instr), 32)
                     irs.append(AssignBlock(assignments, assignblock.instr))
                 irblocks[blk_idx] = IRBlock(irblock.label, irs)
 
@@ -72,8 +72,8 @@ class mipsCGen(CGen):
         lbl = self.get_block_post_label(block)
         out = (self.CODE_RETURN_NO_EXCEPTION % (self.label_to_jitlabel(lbl),
                                                 self.C_PC,
-                                                m2_expr.ExprId('branch_dst_irdst'),
-                                                m2_expr.ExprId('branch_dst_irdst'),
+                                                m2_expr.ExprId('branch_dst_irdst', 32),
+                                                m2_expr.ExprId('branch_dst_irdst', 32),
                                                 self.id_to_c(m2_expr.ExprInt(lbl.offset, 32)))
               ).split('\n')
         return out
diff --git a/miasm2/arch/mips32/regs.py b/miasm2/arch/mips32/regs.py
index fbd55a46..afade869 100644
--- a/miasm2/arch/mips32/regs.py
+++ b/miasm2/arch/mips32/regs.py
@@ -12,8 +12,8 @@ gen_reg('R_HI', globals())
 
 exception_flags = ExprId('exception_flags', 32)
 
-PC_init = ExprId("PC_init")
-PC_FETCH_init = ExprId("PC_FETCH_init")
+PC_init = ExprId("PC_init", 32)
+PC_FETCH_init = ExprId("PC_FETCH_init", 32)
 
 regs32_str = ["ZERO", 'AT', 'V0', 'V1'] +\
     ['A%d'%i for i in xrange(4)] +\
diff --git a/miasm2/arch/mips32/sem.py b/miasm2/arch/mips32/sem.py
index 645f9a4f..855cb6c8 100644
--- a/miasm2/arch/mips32/sem.py
+++ b/miasm2/arch/mips32/sem.py
@@ -34,7 +34,7 @@ def jal(arg1):
     "Jumps to the calculated address @arg1 and stores the return address in $RA"
     PC = arg1
     ir.IRDst = arg1
-    RA = ExprId(ir.get_next_break_label(instr))
+    RA = ExprId(ir.get_next_break_label(instr), 32)
 
 @sbuild.parse
 def jalr(arg1, arg2):
@@ -42,13 +42,13 @@ def jalr(arg1, arg2):
     address in another register @arg2"""
     PC = arg1
     ir.IRDst = arg1
-    arg2 = ExprId(ir.get_next_break_label(instr))
+    arg2 = ExprId(ir.get_next_break_label(instr), 32)
 
 @sbuild.parse
 def bal(arg1):
     PC = arg1
     ir.IRDst = arg1
-    RA = ExprId(ir.get_next_break_label(instr))
+    RA = ExprId(ir.get_next_break_label(instr), 32)
 
 @sbuild.parse
 def l_b(arg1):
@@ -75,7 +75,7 @@ def lb(arg1, arg2):
 @sbuild.parse
 def beq(arg1, arg2, arg3):
     "Branches on @arg3 if the quantities of two registers @arg1, @arg2 are eq"
-    dst = ExprId(ir.get_next_break_label(instr)) if arg1 - arg2 else arg3
+    dst = ExprId(ir.get_next_break_label(instr), 32) if arg1 - arg2 else arg3
     PC = dst
     ir.IRDst = dst
 
@@ -83,7 +83,7 @@ def beq(arg1, arg2, arg3):
 def bgez(arg1, arg2):
     """Branches on @arg2 if the quantities of register @arg1 is greater than or
     equal to zero"""
-    dst = ExprId(ir.get_next_break_label(instr)) if arg1.msb() else arg2
+    dst = ExprId(ir.get_next_break_label(instr), 32) if arg1.msb() else arg2
     PC = dst
     ir.IRDst = dst
 
@@ -91,7 +91,7 @@ def bgez(arg1, arg2):
 def bne(arg1, arg2, arg3):
     """Branches on @arg3 if the quantities of two registers @arg1, @arg2 are NOT
     equal"""
-    dst = arg3 if arg1 - arg2 else ExprId(ir.get_next_break_label(instr))
+    dst = arg3 if arg1 - arg2 else ExprId(ir.get_next_break_label(instr), 32)
     PC = dst
     ir.IRDst = dst
 
@@ -229,7 +229,7 @@ def seh(arg1, arg2):
 @sbuild.parse
 def bltz(arg1, arg2):
     """Branches on @arg2 if the register @arg1 is less than zero"""
-    dst_o = arg2 if arg1.msb() else ExprId(ir.get_next_break_label(instr))
+    dst_o = arg2 if arg1.msb() else ExprId(ir.get_next_break_label(instr), 32)
     PC = dst_o
     ir.IRDst = dst_o
 
@@ -237,7 +237,7 @@ def bltz(arg1, arg2):
 def blez(arg1, arg2):
     """Branches on @arg2 if the register @arg1 is less than or equal to zero"""
     cond = (i1(1) if arg1 else i1(0)) | arg1.msb()
-    dst_o = arg2 if cond else ExprId(ir.get_next_break_label(instr))
+    dst_o = arg2 if cond else ExprId(ir.get_next_break_label(instr), 32)
     PC = dst_o
     ir.IRDst = dst_o
 
@@ -245,7 +245,7 @@ def blez(arg1, arg2):
 def bgtz(arg1, arg2):
     """Branches on @arg2 if the register @arg1 is greater than zero"""
     cond = (i1(1) if arg1 else i1(0)) | arg1.msb()
-    dst_o = ExprId(ir.get_next_break_label(instr)) if cond else arg2
+    dst_o = ExprId(ir.get_next_break_label(instr), 32) if cond else arg2
     PC = dst_o
     ir.IRDst = dst_o
 
@@ -345,13 +345,13 @@ def c_le_d(arg1, arg2, arg3):
 
 @sbuild.parse
 def bc1t(arg1, arg2):
-    dst_o = arg2 if arg1 else ExprId(ir.get_next_break_label(instr))
+    dst_o = arg2 if arg1 else ExprId(ir.get_next_break_label(instr), 32)
     PC = dst_o
     ir.IRDst = dst_o
 
 @sbuild.parse
 def bc1f(arg1, arg2):
-    dst_o = ExprId(ir.get_next_break_label(instr)) if arg1 else arg2
+    dst_o = ExprId(ir.get_next_break_label(instr), 32) if arg1 else arg2
     PC = dst_o
     ir.IRDst = dst_o
 
diff --git a/miasm2/arch/sh4/arch.py b/miasm2/arch/sh4/arch.py
index eeafd5f5..d7ae4f12 100644
--- a/miasm2/arch/sh4/arch.py
+++ b/miasm2/arch/sh4/arch.py
@@ -7,9 +7,9 @@ from collections import defaultdict
 import miasm2.arch.sh4.regs as regs_module
 from miasm2.arch.sh4.regs import *
 
-jra = ExprId('jra')
-jrb = ExprId('jrb')
-jrc = ExprId('jrc')
+jra = ExprId('jra', 32)
+jrb = ExprId('jrb', 32)
+jrc = ExprId('jrc', 32)
 
 
 # parser helper ###########
diff --git a/miasm2/arch/x86/regs.py b/miasm2/arch/x86/regs.py
index cb7e0d7b..84590c75 100644
--- a/miasm2/arch/x86/regs.py
+++ b/miasm2/arch/x86/regs.py
@@ -251,23 +251,23 @@ reg_float_address = 'reg_float_address'
 reg_float_ds = 'reg_float_ds'
 
 
-dr0 = ExprId(reg_dr0)
-dr1 = ExprId(reg_dr1)
-dr2 = ExprId(reg_dr2)
-dr3 = ExprId(reg_dr3)
-dr4 = ExprId(reg_dr4)
-dr5 = ExprId(reg_dr5)
-dr6 = ExprId(reg_dr6)
-dr7 = ExprId(reg_dr7)
-
-cr0 = ExprId(reg_cr0)
-cr1 = ExprId(reg_cr1)
-cr2 = ExprId(reg_cr2)
-cr3 = ExprId(reg_cr3)
-cr4 = ExprId(reg_cr4)
-cr5 = ExprId(reg_cr5)
-cr6 = ExprId(reg_cr6)
-cr7 = ExprId(reg_cr7)
+dr0 = ExprId(reg_dr0, 32)
+dr1 = ExprId(reg_dr1, 32)
+dr2 = ExprId(reg_dr2, 32)
+dr3 = ExprId(reg_dr3, 32)
+dr4 = ExprId(reg_dr4, 32)
+dr5 = ExprId(reg_dr5, 32)
+dr6 = ExprId(reg_dr6, 32)
+dr7 = ExprId(reg_dr7, 32)
+
+cr0 = ExprId(reg_cr0, 32)
+cr1 = ExprId(reg_cr1, 32)
+cr2 = ExprId(reg_cr2, 32)
+cr3 = ExprId(reg_cr3, 32)
+cr4 = ExprId(reg_cr4, 32)
+cr5 = ExprId(reg_cr5, 32)
+cr6 = ExprId(reg_cr6, 32)
+cr7 = ExprId(reg_cr7, 32)
 
 mm0 = ExprId(reg_mm0, 64)
 mm1 = ExprId(reg_mm1, 64)
@@ -330,9 +330,9 @@ float_c2 = ExprId(reg_float_c2, size=1)
 float_c3 = ExprId(reg_float_c3, size=1)
 float_stack_ptr = ExprId(reg_float_stack_ptr, size=3)
 float_control = ExprId(reg_float_control, 16)
-float_eip = ExprId(reg_float_eip)
+float_eip = ExprId(reg_float_eip, 32)
 float_cs = ExprId(reg_float_cs, size=16)
-float_address = ExprId(reg_float_address)
+float_address = ExprId(reg_float_address, 32)
 float_ds = ExprId(reg_float_ds, size=16)
 
 float_st0 = ExprId("float_st0", 64)
@@ -352,14 +352,14 @@ float_replace = {fltregs32_expr[i]: float_list[i] for i in xrange(8)}
 float_replace[r_st_all.expr[0]] = float_st0
 
 
-EAX_init = ExprId('EAX_init')
-EBX_init = ExprId('EBX_init')
-ECX_init = ExprId('ECX_init')
-EDX_init = ExprId('EDX_init')
-ESI_init = ExprId('ESI_init')
-EDI_init = ExprId('EDI_init')
-ESP_init = ExprId('ESP_init')
-EBP_init = ExprId('EBP_init')
+EAX_init = ExprId('EAX_init', 32)
+EBX_init = ExprId('EBX_init', 32)
+ECX_init = ExprId('ECX_init', 32)
+EDX_init = ExprId('EDX_init', 32)
+ESI_init = ExprId('ESI_init', 32)
+EDI_init = ExprId('EDI_init', 32)
+ESP_init = ExprId('ESP_init', 32)
+EBP_init = ExprId('EBP_init', 32)
 
 
 RAX_init = ExprId('RAX_init', 64)
diff --git a/miasm2/arch/x86/sem.py b/miasm2/arch/x86/sem.py
index ddc8aaf9..589c2eb9 100644
--- a/miasm2/arch/x86/sem.py
+++ b/miasm2/arch/x86/sem.py
@@ -5111,7 +5111,7 @@ class ir_x86_16(IntermediateRepresentation):
 
     def irbloc_fix_regs_for_mode(self, irblock, mode=64):
         irs = []
-        for assignblk in irblock.irs:
+        for assignblk in irblock:
             new_assignblk = dict(assignblk)
             for dst, src in assignblk.iteritems():
                 del new_assignblk[dst]
diff --git a/miasm2/expression/expression.py b/miasm2/expression/expression.py
index 6b189c4d..a72c1ec4 100644
--- a/miasm2/expression/expression.py
+++ b/miasm2/expression/expression.py
@@ -525,11 +525,14 @@ class ExprId(Expr):
 
     __slots__ = Expr.__slots__ + ["_name"]
 
-    def __init__(self, name, size=32):
+    def __init__(self, name, size=None):
         """Create an identifier
         @name: str, identifier's name
         @size: int, identifier's size
         """
+        if size is None:
+            warnings.warn('DEPRECATION WARNING: size is a mandatory argument: use ExprId(name, SIZE)')
+            size = 32
         super(ExprId, self).__init__(size)
         self._name = name
 
diff --git a/miasm2/expression/simplifications_cond.py b/miasm2/expression/simplifications_cond.py
index 3054d92b..6bdc810f 100644
--- a/miasm2/expression/simplifications_cond.py
+++ b/miasm2/expression/simplifications_cond.py
@@ -19,9 +19,9 @@ import miasm2.expression.expression as m2_expr
 
 # Jokers for expression matching
 
-jok1 = m2_expr.ExprId("jok1")
-jok2 = m2_expr.ExprId("jok2")
-jok3 = m2_expr.ExprId("jok3")
+jok1 = m2_expr.ExprId("jok1", 32)
+jok2 = m2_expr.ExprId("jok2", 32)
+jok3 = m2_expr.ExprId("jok3", 32)
 jok_small = m2_expr.ExprId("jok_small", 1)
 
 
diff --git a/miasm2/ir/ir.py b/miasm2/ir/ir.py
index afb6b382..64eb3463 100644
--- a/miasm2/ir/ir.py
+++ b/miasm2/ir/ir.py
@@ -258,25 +258,43 @@ class IRBlock(object):
     Stand for an intermediate representation  basic block.
     """
 
-    __slots__ = ["label", "_assignments", "_dst", "_dst_linenb"]
+    __slots__ = ["label", "_assignblks", "_dst", "_dst_linenb"]
 
-    def __init__(self, label, irs):
+    def __init__(self, label, assignblks):
         """
         @label: AsmLabel of the IR basic block
-        @irs: list of AssignBlock
+        @assignblks: list of AssignBlock
         """
 
         assert isinstance(label, AsmLabel)
         self.label = label
-        for assignblk in irs:
+        for assignblk in assignblks:
             assert isinstance(assignblk, AssignBlock)
-        self._assignments = tuple(irs)
+        self._assignblks = tuple(assignblks)
         self._dst = None
         self._dst_linenb = None
 
+
+    @property
+    def assignblks(self):
+        return self._assignblks
+
     @property
     def irs(self):
-        return self._assignments
+        warnings.warn('DEPRECATION WARNING: use "irblock.assignblks" instead of "irblock.irs"')
+        return self._assignblks
+
+    def __iter__(self):
+        """Iterate on assignblks"""
+        return self._assignblks.__iter__()
+
+    def __getitem__(self, index):
+        """Getitem on assignblks"""
+        return self._assignblks.__getitem__(index)
+
+    def __len__(self):
+        """Length of assignblks"""
+        return self._assignblks.__len__()
 
     def is_dst_set(self):
         return self._dst is not None
@@ -284,7 +302,7 @@ class IRBlock(object):
     def cache_dst(self):
         final_dst = None
         final_linenb = None
-        for linenb, assignblk in enumerate(self.irs):
+        for linenb, assignblk in enumerate(self):
             for dst, src in assignblk.iteritems():
                 if dst.is_id("IRDst"):
                     if final_dst is not None:
@@ -306,7 +324,7 @@ class IRBlock(object):
         """Generate a new IRBlock with a dst (IRBlock) fixed to @value"""
         irs = []
         dst_found = False
-        for assignblk in self.irs:
+        for assignblk in self:
             new_assignblk = {}
             for dst, src in assignblk.iteritems():
                 if dst.is_id("IRDst"):
@@ -328,7 +346,7 @@ class IRBlock(object):
     def __str__(self):
         out = []
         out.append('%s' % self.label)
-        for assignblk in self.irs:
+        for assignblk in self:
             for dst, src in assignblk.iteritems():
                 out.append('\t%s = %s' % (dst, src))
             out.append("")
@@ -349,7 +367,7 @@ class IRBlock(object):
             mod_src = lambda expr:expr
 
         assignblks = []
-        for assignblk in self.irs:
+        for assignblk in self:
             new_assignblk = {}
             for dst, src in assignblk.iteritems():
                 new_assignblk[mod_dst(dst)] = mod_src(src)
@@ -387,7 +405,7 @@ class DiGraphIR(DiGraph):
         if node not in self._blocks:
             yield [self.DotCellDescription(text="NOT PRESENT", attr={})]
             raise StopIteration
-        for i, assignblk in enumerate(self._blocks[node].irs):
+        for i, assignblk in enumerate(self._blocks[node]):
             for dst, src in assignblk.iteritems():
                 line = "%s = %s" % (dst, src)
                 if self._dot_offset:
@@ -456,7 +474,7 @@ class IntermediateRepresentation(object):
         ir_bloc_cur, extra_irblocks = self.get_ir(instr)
         for index, irb in enumerate(extra_irblocks):
             irs = []
-            for assignblk in irb.irs:
+            for assignblk in irb:
                 irs.append(AssignBlock(assignblk, instr))
             extra_irblocks[index] = IRBlock(irb.label, irs)
         assignblk = AssignBlock(ir_bloc_cur, instr)
@@ -502,7 +520,7 @@ class IntermediateRepresentation(object):
     def getby_offset(self, offset):
         out = set()
         for irb in self.blocks.values():
-            for assignblk in irb.irs:
+            for assignblk in irb:
                 instr = assignblk.instr
                 if instr.offset <= offset < instr.offset + instr.l:
                     out.add(irb)
@@ -607,11 +625,12 @@ class IntermediateRepresentation(object):
         return irblock
 
     def is_pc_written(self, block):
+        """Return the first Assignblk of the @blockin which PC is written
+        @block: IRBlock instance"""
         all_pc = self.arch.pc.values()
-        for irs in block.irs:
-            for assignblk in irs:
-                if assignblk.dst in all_pc:
-                    return assignblk
+        for assignblk in block:
+            if assignblk.dst in all_pc:
+                return assignblk
         return None
 
     def set_empty_dst_to_next(self, block, ir_blocks):
@@ -625,8 +644,8 @@ class IntermediateRepresentation(object):
             else:
                 dst = m2_expr.ExprId(next_lbl,
                                      self.pc.size)
-            assignblk = AssignBlock({self.IRDst: dst}, irblock.irs[-1].instr)
-            ir_blocks[index] = IRBlock(irblock.label, list(irblock.irs) + [assignblk])
+            assignblk = AssignBlock({self.IRDst: dst}, irblock[-1].instr)
+            ir_blocks[index] = IRBlock(irblock.label, list(irblock.assignblks) + [assignblk])
 
     def post_add_block(self, block, ir_blocks):
         self.set_empty_dst_to_next(block, ir_blocks)
@@ -670,13 +689,13 @@ class IntermediateRepresentation(object):
         """
         for label, block in self.blocks.iteritems():
             assignblks = []
-            for assignblk in block.irs:
+            for assignblk in block:
                 new_assignblk = assignblk.simplify(simplifier)
                 assignblks.append(new_assignblk)
             self.blocks[label] = IRBlock(label, assignblks)
 
     def replace_expr_in_ir(self, bloc, rep):
-        for assignblk in bloc.irs:
+        for assignblk in bloc:
             for dst, src in assignblk.items():
                 del assignblk[dst]
                 assignblk[dst.replace_expr(rep)] = src.replace_expr(rep)
@@ -720,7 +739,7 @@ class IntermediateRepresentation(object):
         todo = set([irb.dst])
         done = set()
 
-        for assignblk in reversed(irb.irs):
+        for assignblk in reversed(irb):
             if not todo:
                 break
             out = self._extract_dst(todo, done)
@@ -746,7 +765,7 @@ class IntermediateRepresentation(object):
             for dst in self.dst_trackback(block):
                 if dst.is_int():
                     dst_lbl = self.symbol_pool.getby_offset_create(int(dst))
-                    dst = m2_expr.ExprId(dst_lbl)
+                    dst = m2_expr.ExprId(dst_lbl, self.pc.size)
                 if expr_is_label(dst):
                     self._graph.add_edge(lbl, dst.name)
 
@@ -762,7 +781,7 @@ class IntermediateRepresentation(object):
         modified = False
         for label, block in self.blocks.iteritems():
             irs = []
-            for assignblk in block.irs:
+            for assignblk in block:
                 if len(assignblk):
                     irs.append(assignblk)
                 else:
@@ -779,9 +798,9 @@ class IntermediateRepresentation(object):
         # Find candidates
         jmp_blocks = set()
         for block in self.blocks.itervalues():
-            if len(block.irs) != 1:
+            if len(block) != 1:
                 continue
-            assignblk = block.irs[0]
+            assignblk = block[0]
             if len(assignblk) > 1:
                 continue
             assert set(assignblk.keys()) == set([self.IRDst])
@@ -860,7 +879,7 @@ class IntermediateRepresentation(object):
                 continue
             # Block has one son, son has one parent => merge
             assignblks =[]
-            for assignblk in self.blocks[block].irs:
+            for assignblk in self.blocks[block]:
                 if self.IRDst not in assignblk:
                     assignblks.append(assignblk)
                     continue
@@ -870,7 +889,7 @@ class IntermediateRepresentation(object):
                         affs[dst] = src
                 assignblks.append(AssignBlock(affs, assignblk.instr))
 
-            assignblks += self.blocks[son].irs
+            assignblks += self.blocks[son].assignblks
             new_block = IRBlock(block, assignblks)
 
             self.graph.discard_edge(block, son)
diff --git a/miasm2/ir/symbexec.py b/miasm2/ir/symbexec.py
index 593ab49a..8ecde21c 100644
--- a/miasm2/ir/symbexec.py
+++ b/miasm2/ir/symbexec.py
@@ -524,7 +524,7 @@ class SymbolicExecutionEngine(object):
         @irb: irbloc instance
         @step: display intermediate steps
         """
-        for assignblk in irb.irs:
+        for assignblk in irb:
             if step:
                 print 'Instr', assignblk.instr
                 print 'Assignblk:'
diff --git a/miasm2/jitter/codegen.py b/miasm2/jitter/codegen.py
index 61a9a784..9ed55f37 100644
--- a/miasm2/jitter/codegen.py
+++ b/miasm2/jitter/codegen.py
@@ -489,7 +489,7 @@ class CGen(object):
         for irblock in irblocks:
             attributes = []
             irblocks_attributes.append(attributes)
-            for assignblk in irblock.irs:
+            for assignblk in irblock:
                 attrib = Attributes(log_mn, log_regs)
                 attributes.append(attrib)
                 self.get_caracteristics(assignblk, attrib)
@@ -534,7 +534,7 @@ class CGen(object):
 
         out = []
         dst2index = None
-        for index, assignblk in enumerate(irblock.irs):
+        for index, assignblk in enumerate(irblock):
             if index == irblock.dst_linenb:
                 c_dst, dst2index = self.gen_assignblk_dst(irblock.dst)
             else:
diff --git a/miasm2/jitter/jitcore_python.py b/miasm2/jitter/jitcore_python.py
index 6d954aae..a74ef7e6 100644
--- a/miasm2/jitter/jitcore_python.py
+++ b/miasm2/jitter/jitcore_python.py
@@ -72,7 +72,7 @@ class JitCore_Python(jitcore.JitCore):
                 exec_engine.update_engine_from_cpu()
 
                 # Execute current ir bloc
-                for assignblk in irb.irs:
+                for assignblk in irb:
                     instr = assignblk.instr
                     # For each new instruction (in assembly)
                     if instr.offset not in offsets_jitted:
diff --git a/miasm2/jitter/llvmconvert.py b/miasm2/jitter/llvmconvert.py
index 83349781..65c6aa07 100644
--- a/miasm2/jitter/llvmconvert.py
+++ b/miasm2/jitter/llvmconvert.py
@@ -966,7 +966,7 @@ class LLVMFunction():
         if isinstance(offset, (int, long)):
             offset = self.add_ir(m2_expr.ExprInt(offset, PC.size))
         self.affect(offset, PC)
-        self.affect(self.add_ir(m2_expr.ExprInt(1, 8)), m2_expr.ExprId("status"))
+        self.affect(self.add_ir(m2_expr.ExprInt(1, 8)), m2_expr.ExprId("status", 32))
         self.set_ret(offset)
 
         builder.position_at_end(merge_block)
@@ -1013,7 +1013,7 @@ class LLVMFunction():
         if isinstance(offset, (int, long)):
             offset = self.add_ir(m2_expr.ExprInt(offset, PC.size))
         self.affect(offset, PC)
-        self.affect(self.add_ir(m2_expr.ExprInt(1, 8)), m2_expr.ExprId("status"))
+        self.affect(self.add_ir(m2_expr.ExprInt(1, 8)), m2_expr.ExprId("status", 32))
         self.set_ret(offset)
 
         builder.position_at_end(merge_block)
@@ -1121,7 +1121,7 @@ class LLVMFunction():
         self.gen_post_code(attrib)
         self.affect(dst, PC)
         self.gen_post_instr_checks(attrib, dst)
-        self.affect(self.add_ir(m2_expr.ExprInt(0, 8)), m2_expr.ExprId("status"))
+        self.affect(self.add_ir(m2_expr.ExprInt(0, 8)), m2_expr.ExprId("status", 32))
         self.set_ret(dst)
 
 
@@ -1138,7 +1138,7 @@ class LLVMFunction():
         case_value = None
         instr = instr_attrib.instr
 
-        for index, assignblk in enumerate(irblock.irs):
+        for index, assignblk in enumerate(irblock):
             # Enable cache
             self.main_stream = True
             self.expr_cache = {}
@@ -1215,7 +1215,7 @@ class LLVMFunction():
         m2_exception_flag = self.llvm_context.ir_arch.arch.regs.exception_flags
         t_size = LLVMType.IntType(m2_exception_flag.size)
         self.affect(self.add_ir(m2_expr.ExprInt(1, 8)),
-                    m2_expr.ExprId("status"))
+                    m2_expr.ExprId("status", 32))
         self.affect(t_size(m2_csts.EXCEPT_UNK_MNEMO),
                     m2_exception_flag)
         self.set_ret(LLVMType.IntType(64)(asmblock.label.offset))
@@ -1233,7 +1233,7 @@ class LLVMFunction():
 
             # Common code
             self.affect(self.add_ir(m2_expr.ExprInt(0, 8)),
-                        m2_expr.ExprId("status"))
+                        m2_expr.ExprId("status", 32))
 
             # Check if IRDst has been set
             zero_casted = LLVMType.IntType(codegen.delay_slot_set.size)(0)
@@ -1257,7 +1257,7 @@ class LLVMFunction():
             to_ret = self.add_ir(codegen.delay_slot_dst)
             self.affect(to_ret, PC)
             self.affect(self.add_ir(m2_expr.ExprInt(0, 8)),
-                        m2_expr.ExprId("status"))
+                        m2_expr.ExprId("status", 32))
             self.set_ret(to_ret)
 
             # Else Block
@@ -1272,16 +1272,16 @@ class LLVMFunction():
         Prototype : f(i8* jitcpu, i8* vmcpu, i8* vmmngr, i8* status)"""
 
         # Build function signature
-        self.my_args.append((m2_expr.ExprId("jitcpu"),
+        self.my_args.append((m2_expr.ExprId("jitcpu", 32),
                              llvm_ir.PointerType(LLVMType.IntType(8)),
                              "jitcpu"))
-        self.my_args.append((m2_expr.ExprId("vmcpu"),
+        self.my_args.append((m2_expr.ExprId("vmcpu", 32),
                              llvm_ir.PointerType(LLVMType.IntType(8)),
                              "vmcpu"))
-        self.my_args.append((m2_expr.ExprId("vmmngr"),
+        self.my_args.append((m2_expr.ExprId("vmmngr", 32),
                              llvm_ir.PointerType(LLVMType.IntType(8)),
                              "vmmngr"))
-        self.my_args.append((m2_expr.ExprId("status"),
+        self.my_args.append((m2_expr.ExprId("status", 32),
                              llvm_ir.PointerType(LLVMType.IntType(8)),
                              "status"))
         ret_size = 64
diff --git a/test/analysis/data_flow.py b/test/analysis/data_flow.py
index 2c24773a..dff88470 100644
--- a/test/analysis/data_flow.py
+++ b/test/analysis/data_flow.py
@@ -5,20 +5,20 @@ from miasm2.analysis.data_flow import *
 from miasm2.ir.analysis import ira
 from miasm2.ir.ir import IRBlock, AssignBlock
 
-a = ExprId("a")
-b = ExprId("b")
-c = ExprId("c")
-d = ExprId("d")
-r = ExprId("r")
+a = ExprId("a", 32)
+b = ExprId("b", 32)
+c = ExprId("c", 32)
+d = ExprId("d", 32)
+r = ExprId("r", 32)
 
-a_init = ExprId("a_init")
-b_init = ExprId("b_init")
-c_init = ExprId("c_init")
-d_init = ExprId("d_init")
-r_init = ExprId("r_init") # Return register
+a_init = ExprId("a_init", 32)
+b_init = ExprId("b_init", 32)
+c_init = ExprId("c_init", 32)
+d_init = ExprId("d_init", 32)
+r_init = ExprId("r_init", 32) # Return register
 
-pc = ExprId("pc")
-sp = ExprId("sp")
+pc = ExprId("pc", 32)
+sp = ExprId("sp", 32)
 
 CST1 = ExprInt(0x11, 32)
 CST2 = ExprInt(0x12, 32)
@@ -635,7 +635,7 @@ G17_EXP_IRB0 = gen_irblock(LBL0, [[],
                                    ExprAff(b, a),
                                    ExprAff(c, b)],
 
-                                  G17_IRB0.irs[14]
+                                  G17_IRB0[14]
                                   # Trick because a+b+c != ((a+b)+c)
                                  ])
 
@@ -684,4 +684,4 @@ for test_nb, test in enumerate([(G1_IRA, G1_EXP_IRA),
     # Check that each expr in the blocks are the same
     for lbl, irb in g_ira.blocks.iteritems():
         exp_irb = g_exp_ira.blocks[lbl]
-        assert exp_irb.irs == irb.irs
+        assert exp_irb.assignblks == irb.assignblks
diff --git a/test/analysis/depgraph.py b/test/analysis/depgraph.py
index 63313861..9fb046d0 100644
--- a/test/analysis/depgraph.py
+++ b/test/analysis/depgraph.py
@@ -16,19 +16,19 @@ except ImportError:
     EMULATION = False
 
 STEP_COUNTER = count()
-A = ExprId("a")
-B = ExprId("b")
-C = ExprId("c")
-D = ExprId("d")
-R = ExprId("r")
+A = ExprId("a", 32)
+B = ExprId("b", 32)
+C = ExprId("c", 32)
+D = ExprId("d", 32)
+R = ExprId("r", 32)
 
-A_INIT = ExprId("a_init")
-B_INIT = ExprId("b_init")
-C_INIT = ExprId("c_init")
-D_INIT = ExprId("d_init")
+A_INIT = ExprId("a_init", 32)
+B_INIT = ExprId("b_init", 32)
+C_INIT = ExprId("c_init", 32)
+D_INIT = ExprId("d_init", 32)
 
-PC = ExprId("pc")
-SP = ExprId("sp")
+PC = ExprId("pc", 32)
+SP = ExprId("sp", 32)
 
 CST0 = ExprInt(0x0, 32)
 CST1 = ExprInt(0x1, 32)
@@ -132,7 +132,7 @@ def bloc2graph(irgraph, label=False, lines=True):
             label_attr, label_name)
         block_html_lines = []
         if lines and irblock is not None:
-            for assignblk in irblock.irs:
+            for assignblk in irblock:
                 for dst, src in assignblk.iteritems():
                     if False:
                         out_render = "%.8X</td><td %s> " % (0, td_attr)
@@ -277,8 +277,8 @@ G4_IRA = IRATest()
 G4_IRB0 = gen_irblock(LBL0, [[ExprAff(C, CST1)]])
 G4_IRB1 = gen_irblock(LBL1, [[ExprAff(C, C + CST2)],
                              [ExprAff(G4_IRA.IRDst,
-                                      ExprCond(C, ExprId(LBL2),
-                                               ExprId(LBL1)))]])
+                                      ExprCond(C, ExprId(LBL2, 32),
+                                               ExprId(LBL1, 32)))]])
 
 G4_IRB2 = gen_irblock(LBL2, [[ExprAff(A, B)]])
 
@@ -296,8 +296,8 @@ G5_IRA = IRATest()
 G5_IRB0 = gen_irblock(LBL0, [[ExprAff(B, CST1)]])
 G5_IRB1 = gen_irblock(LBL1, [[ExprAff(B, B + CST2)],
                              [ExprAff(G5_IRA.IRDst,
-                                      ExprCond(B, ExprId(LBL2),
-                                               ExprId(LBL1)))]])
+                                      ExprCond(B, ExprId(LBL2, 32),
+                                               ExprId(LBL1, 32)))]])
 
 G5_IRB2 = gen_irblock(LBL2, [[ExprAff(A, B)]])
 
@@ -400,16 +400,16 @@ G13_IRA = IRATest()
 G13_IRB0 = gen_irblock(LBL0, [[ExprAff(A, CST1)],
                               #[ExprAff(B, A)],
                               [ExprAff(G13_IRA.IRDst,
-                                       ExprId(LBL1))]])
+                                       ExprId(LBL1, 32))]])
 G13_IRB1 = gen_irblock(LBL1, [[ExprAff(C, A)],
                               #[ExprAff(A, A + CST1)],
                               [ExprAff(G13_IRA.IRDst,
-                                       ExprCond(R, ExprId(LBL2),
-                                                ExprId(LBL1)))]])
+                                       ExprCond(R, ExprId(LBL2, 32),
+                                                ExprId(LBL1, 32)))]])
 
 G13_IRB2 = gen_irblock(LBL2, [[ExprAff(B, A + CST3)], [ExprAff(A, B + CST3)],
                               [ExprAff(G13_IRA.IRDst,
-                                       ExprId(LBL1))]])
+                                       ExprId(LBL1, 32))]])
 
 G13_IRB3 = gen_irblock(LBL3, [[ExprAff(R, C)]])
 
@@ -427,18 +427,18 @@ G14_IRA = IRATest()
 
 G14_IRB0 = gen_irblock(LBL0, [[ExprAff(A, CST1)],
                               [ExprAff(G14_IRA.IRDst,
-                                       ExprId(LBL1))]
+                                       ExprId(LBL1, 32))]
                              ])
 G14_IRB1 = gen_irblock(LBL1, [[ExprAff(B, A)],
                               [ExprAff(G14_IRA.IRDst,
-                                       ExprCond(C, ExprId(LBL2),
-                                                ExprId(LBL3)))]
+                                       ExprCond(C, ExprId(LBL2, 32),
+                                                ExprId(LBL3, 32)))]
                              ])
 
 G14_IRB2 = gen_irblock(LBL2, [[ExprAff(D, A)],
                               [ExprAff(A, D + CST1)],
                               [ExprAff(G14_IRA.IRDst,
-                                       ExprId(LBL1))]
+                                       ExprId(LBL1, 32))]
                              ])
 
 G14_IRB3 = gen_irblock(LBL3, [[ExprAff(R, D + B)]])
@@ -510,72 +510,72 @@ G17_IRA.blocks = dict([(irb.label, irb) for irb in [G17_IRB0, G17_IRB1,
 
 # Test graph 1
 G1_TEST1_DN1 = DependencyNode(
-    G1_IRB2.label, A, len(G1_IRB2.irs))
+    G1_IRB2.label, A, len(G1_IRB2))
 
 G1_INPUT = (set([G1_TEST1_DN1]), set([G1_IRB0.label]))
 
 # Test graph 2
 
 G2_TEST1_DN1 = DependencyNode(
-    G2_IRB2.label, A, len(G2_IRB2.irs))
+    G2_IRB2.label, A, len(G2_IRB2))
 
 G2_INPUT = (set([G2_TEST1_DN1]), set([G2_IRB0.label]))
 
 # Test graph 3
 
 G3_TEST1_0_DN1 = DependencyNode(
-    G3_IRB3.label, A, len(G3_IRB3.irs))
+    G3_IRB3.label, A, len(G3_IRB3))
 
 G3_INPUT = (set([G3_TEST1_0_DN1]), set([G3_IRB0.label]))
 
 # Test graph 4
 
 G4_TEST1_DN1 = DependencyNode(
-    G4_IRB2.label, A, len(G2_IRB0.irs))
+    G4_IRB2.label, A, len(G2_IRB0))
 
 G4_INPUT = (set([G4_TEST1_DN1]), set([G4_IRB0.label]))
 
 # Test graph 5
 
 G5_TEST1_0_DN1 = DependencyNode(
-    G5_IRB2.label, A, len(G5_IRB2.irs))
+    G5_IRB2.label, A, len(G5_IRB2))
 
 G5_INPUT = (set([G5_TEST1_0_DN1]), set([G5_IRB0.label]))
 
 # Test graph 6
 
 G6_TEST1_0_DN1 = DependencyNode(
-    G6_IRB1.label, A, len(G6_IRB1.irs))
+    G6_IRB1.label, A, len(G6_IRB1))
 
 G6_INPUT = (set([G6_TEST1_0_DN1]), set([G6_IRB0.label]))
 
 # Test graph 7
 
 G7_TEST1_0_DN1 = DependencyNode(
-    G7_IRB2.label, D, len(G7_IRB2.irs))
+    G7_IRB2.label, D, len(G7_IRB2))
 
 G7_INPUT = (set([G7_TEST1_0_DN1]), set([G7_IRB0.label]))
 
 # Test graph 8
 
 G8_TEST1_0_DN1 = DependencyNode(
-    G8_IRB2.label, A, len(G8_IRB2.irs))
+    G8_IRB2.label, A, len(G8_IRB2))
 
 G8_INPUT = (set([G8_TEST1_0_DN1]), set([G3_IRB0.label]))
 
 # Test 9: Multi elements
 
 G9_TEST1_0_DN1 = DependencyNode(
-    G8_IRB2.label, A, len(G8_IRB2.irs))
+    G8_IRB2.label, A, len(G8_IRB2))
 G9_TEST1_0_DN5 = DependencyNode(
-    G8_IRB2.label, C, len(G8_IRB2.irs))
+    G8_IRB2.label, C, len(G8_IRB2))
 
 G9_INPUT = (set([G9_TEST1_0_DN1, G9_TEST1_0_DN5]), set([G8_IRB0.label]))
 
 # Test 10: loop at beginning
 
 G10_TEST1_0_DN1 = DependencyNode(
-    G10_IRB2.label, A, len(G10_IRB2.irs))
+    G10_IRB2.label, A, len(G10_IRB2))
 
 G10_INPUT = (set([G10_TEST1_0_DN1]), set([G10_IRB1.label]))
 
@@ -583,7 +583,7 @@ G10_INPUT = (set([G10_TEST1_0_DN1]), set([G10_IRB1.label]))
 # Test 11: no dual bloc emulation
 
 G11_TEST1_DN1 = DependencyNode(
-    G11_IRB2.label, A, len(G11_IRB2.irs))
+    G11_IRB2.label, A, len(G11_IRB2))
 
 G11_INPUT = (set([G11_TEST1_DN1]), set([G11_IRB0.label]))
 
diff --git a/test/core/sembuilder.py b/test/core/sembuilder.py
index d8fdb6c4..ebf9f385 100644
--- a/test/core/sembuilder.py
+++ b/test/core/sembuilder.py
@@ -8,7 +8,7 @@ from miasm2.core.asmblock import AsmLabel
 # Test classes
 class IR(object):
 
-    IRDst = m2_expr.ExprId("IRDst")
+    IRDst = m2_expr.ExprId("IRDst", 32)
 
     def get_next_instr(self, _):
         return AsmLabel("NEXT")
@@ -41,9 +41,9 @@ def test(Arg1, Arg2, Arg3):
     else:
         alias = {i16(4), i8(5)}
 
-a = m2_expr.ExprId('A')
-b = m2_expr.ExprId('B')
-c = m2_expr.ExprId('C')
+a = m2_expr.ExprId('A', 32)
+b = m2_expr.ExprId('B', 32)
+c = m2_expr.ExprId('C', 32)
 ir = IR()
 instr = Instr()
 res = test(ir, instr, a, b, c)
@@ -59,7 +59,7 @@ for statement in res[0]:
 print "[+] Blocks:"
 for irb in res[1]:
     print irb.label
-    for exprs in irb.irs:
-        for expr in exprs:
+    for assignblk in irb:
+        for expr in assignblk:
             print expr
         print
diff --git a/test/expression/expression.py b/test/expression/expression.py
index ac145a04..6bb6d94c 100644
--- a/test/expression/expression.py
+++ b/test/expression/expression.py
@@ -15,7 +15,7 @@ assert big_cst.size == 0x1000
 
 # Possible values
 #- Common constants
-A = ExprId("A")
+A = ExprId("A", 32)
 cond1 = ExprId("cond1", 1)
 cond2 = ExprId("cond2", 16)
 cst1 = ExprInt(1, 32)
diff --git a/test/expression/expression_helper.py b/test/expression/expression_helper.py
index a4c221e9..35873ca4 100755
--- a/test/expression/expression_helper.py
+++ b/test/expression/expression_helper.py
@@ -12,8 +12,8 @@ class TestExpressionExpressionHelper(unittest.TestCase):
 
         # Build a complex expression
         cst = m2_expr.ExprInt(0x100, 16)
-        eax = m2_expr.ExprId("EAX")
-        ebx = m2_expr.ExprId("EBX")
+        eax = m2_expr.ExprId("EAX", 32)
+        ebx = m2_expr.ExprId("EBX", 32)
         ax = eax[0:16]
         expr = eax + ebx
         expr = m2_expr.ExprCompose(ax, expr[16:32])
diff --git a/test/expression/simplifications.py b/test/expression/simplifications.py
index ad420621..1e8e73ba 100644
--- a/test/expression/simplifications.py
+++ b/test/expression/simplifications.py
@@ -8,11 +8,11 @@ from miasm2.expression.simplifications import expr_simp, ExpressionSimplifier
 from miasm2.expression.simplifications_cond import ExprOp_inf_signed, ExprOp_inf_unsigned, ExprOp_equal
 
 # Define example objects
-a = ExprId('a')
-b = ExprId('b')
-c = ExprId('c')
-d = ExprId('d')
-e = ExprId('e')
+a = ExprId('a', 32)
+b = ExprId('b', 32)
+c = ExprId('c', 32)
+d = ExprId('d', 32)
+e = ExprId('e', 32)
 f = ExprId('f', size=64)
 
 m = ExprMem(a)
@@ -378,17 +378,17 @@ for e, e_check in to_test[:]:
 
 
 
-x = ExprId('x')
-y = ExprId('y')
-z = ExprId('z')
-a = ExprId('a')
-b = ExprId('b')
-c = ExprId('c')
+x = ExprId('x', 32)
+y = ExprId('y', 32)
+z = ExprId('z', 32)
+a = ExprId('a', 32)
+b = ExprId('b', 32)
+c = ExprId('c', 32)
 
 
-jra = ExprId('jra')
-jrb = ExprId('jrb')
-jrint1 = ExprId('jrint1')
+jra = ExprId('jra', 32)
+jrb = ExprId('jrb', 32)
+jrint1 = ExprId('jrint1', 32)
 
 
 e1 = ExprMem((a & ExprInt(0xFFFFFFFC, 32)) + ExprInt(0x10, 32), 32)
diff --git a/test/ir/ir.py b/test/ir/ir.py
index 05936d75..3774e4e9 100644
--- a/test/ir/ir.py
+++ b/test/ir/ir.py
@@ -2,8 +2,8 @@ from miasm2.expression.expression import *
 from miasm2.ir.ir import AssignBlock
 from miasm2.expression.simplifications import expr_simp
 
-id_a = ExprId("a")
-id_b = ExprId("b")
+id_a = ExprId("a", 32)
+id_b = ExprId("b", 32)
 int0 = ExprInt(0, id_a.size)
 
 # Test AssignBlock
diff --git a/test/ir/symbexec.py b/test/ir/symbexec.py
index f8d8c7bf..492dcfec 100755
--- a/test/ir/symbexec.py
+++ b/test/ir/symbexec.py
@@ -30,10 +30,10 @@ class TestSymbExec(unittest.TestCase):
         mem40w = ExprMem(addr40, 16)
         mem50v = ExprMem(addr50,  8)
         mem50w = ExprMem(addr50, 16)
-        id_x = ExprId('x')
+        id_x = ExprId('x', 32)
         id_y = ExprId('y', 8)
-        id_a = ExprId('a')
-        id_eax = ExprId('eax_init')
+        id_a = ExprId('a', 32)
+        id_eax = ExprId('eax_init', 32)
 
         e = SymbolicExecutionEngine(ir_x86_32(),
                                     {mem0: id_x, mem1: id_y, mem9: id_x,