diff options
Diffstat (limited to 'results/classifier/deepseek-2-tmp/output/hypervisor/1841491')
| -rw-r--r-- | results/classifier/deepseek-2-tmp/output/hypervisor/1841491 | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/results/classifier/deepseek-2-tmp/output/hypervisor/1841491 b/results/classifier/deepseek-2-tmp/output/hypervisor/1841491 new file mode 100644 index 00000000..2d7f776b --- /dev/null +++ b/results/classifier/deepseek-2-tmp/output/hypervisor/1841491 @@ -0,0 +1,36 @@ + +floating point emulation can fail to set FE_UNDERFLOW + +Floating point emulation can fail to set FE_UNDERFLOW in some circumstances. This shows up often in glibc's "math" tests. A similar test is attached. + +This is similar to bug #1841442, but not the same problem, and I don't think the fix will be in the same code. + +On ppc64le native: +-- +$ gcc -c -O2 fma.c +$ gcc -O2 test-fma.c fma.o -lm -o test-fma +$ ./test-fma $(./test-fma) +fma(0x1.ffffffffffffcp-1022, 0x1.0000000000001p-1, 0x0.0000000000001p-1022) +0x0 + +0xa000000 +FE_INEXACT FE_UNDERFLOW +0x1p-1022 +-- + +On qemu-system-ppc64: +-- +$ ./test-fma $(./test-fma) +fma(0x1.ffffffffffffcp-1022, 0x1.0000000000001p-1, 0x0.0000000000001p-1022) +0x0 + +0x2000000 +FE_INEXACT +0x1p-1022 +-- + +QEMU versions vary, but not too much, and are pretty close to git HEAD: +- 586f3dced9 (HEAD -> master, origin/master, origin/HEAD) Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20190822' into staging +- 864ab31 Update version for v4.1.0-rc4 release + +There are worse symptoms on qemu-x86_64, but this is apparently not surprising per https://bugs.launchpad.net/qemu/+bug/1841442/comments/6. \ No newline at end of file |