[Bug target/50182] Performance degradation from gcc 4.1 (x86_64)

[oleg at smolsky dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50182

--- Comment #36 from oleg at smolsky dot net 2012-03-03 02:59:11 UTC ---
Here is the code emitted by g++ 4.6.3 for smaller_test.cpp (attached to 
the bug)

  unsigned int test_constant<> proc near
                 mov     r9d, cs:iterations
                 xor     r8d, r8d
                 xor     eax, eax
                 test    r9d, r9d
                 jle     short locret_400552
                 db      66h, 66h, 66h
                 nop
                 db      66h, 66h
                 nop

loc_400528:
                 xor     ecx, ecx
                 xor     edx, edx
                 test    esi, esi
                 jle     short loc_40054E

loc_400530:
                 add     edx, 0Ah
                 add     dl, [rdi+rcx]
                 add     rcx, 1
                 cmp     esi, ecx
                 jg      short loc_400530
                 movsx   edx, dl

loc_400541:
                 add     r8d, 1
                 add     eax, edx
                 cmp     r8d, r9d
                 jnz     short loc_400528
                 rep retn

loc_40054E:
                 xor     edx, edx
                 jmp     short loc_400541

locret_400552:
                 rep retn