Question

I found a very strange behaviour when using gcc’s -O3 or -O2 option.

When my program is running under debug mode (-g), it is fine; but it raises a segmentation fault when I turned on -O3 or -O2.

The segmentation happens when it is running a function with SSE2 macro inside; like

_m128i polynomial = _mm_set1_epi8(0x1d)

This is only part of the code.

I think I have already eliminate the situation of address alignment on 16 bytes. It’s so wired that the -g mode and the -O2 or -O3 mode behaves differently.

Actually, I am not sure the bug is related to SSE2 or not.

I am using gcc 4.4.3.

Have you encountered the same problem?

Or can you gave me some suggestion on how to deal with it?

Answer 1

http://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=RESOLVED&resolution=FIXED&target_milestone=4.4.4

Update to a newer version of GCC.