contrib/plugins/howvec.c for ARM64 under constrained Description of problem: Consider the static InsnClassExecCount aarch64_insn_classes array in contrib/plugins/howvec.c There are 5 entries which will never be discovered, and so count as 0; see the dump below. I did not figure out which of prior rows in the table was over-eagerly getting instructions intended for the subsequent counted-as-0 row. ``` udef aka UDEF 65536 sve aka SVE 268435456 res aka Reserved 268369920 pcrel aka PCrel addr 134217728 asit aka Add/Sub (imm,tags) 67108864 asi aka Add/Sub (imm) 67108864 logi aka Logical (imm) 67108864 movwi aka Move Wide (imm) 67108864 bitf aka Bitfield 67108864 extr aka Extract 67108864 dpri aka Data Proc Imm 0 cndb aka Cond Branch (imm) 33554432 excp aka Exception Gen 16777216 nop aka NOP 1 hint aka Hints 4095 barr aka Barriers 4096 psta aka PSTATE 32768 sins aka System Insn 1048576 sreg aka System Reg 2097152 breg aka Branch (reg) 33554432 bimm aka Branch (imm) 134217728 cmpb aka Cmp & Branch 67108864 tstb aka Tst & Branch 67108864 branch aka Branches 181362688 advlsm aka AdvSimd ldstmult 262144 advlsmp aka AdvSimd ldstmult++ 4194304 advlss aka AdvSimd ldst 524288 advlssp aka AdvSimd ldst++ 16777216 ldstx aka ldst excl 67108864 prfm aka Prefetch 16777216 ldlit aka Load Reg (lit) 251658240 ldstnap aka ldst noalloc pair 67108864 ldstp aka ldst pair 469762048 ldstr aka ldst reg 0 atomic aka Atomic ldst 0 ldstro aka ldst reg (reg off) 0 ldstpa aka ldst reg (pac) 0 ldsti aka ldst reg (imm) 134217728 ldst aka Loads & Stores 313786368 dprr aka Data Proc Reg 402653184 fpsimd aka Scalar FP 402653183 unclas aka Unclassified 536870912 ``` Steps to reproduce: 1. Write a simple wrapper program; iterate and search through all 2**32 insns, dump the array 2. 3.