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Re: Fix PR target/19240
BTW: As it is claimed by reporter, mixing 387 and SSE code can introduceThe reporter is back to nominal performance with this patch ;)
Thanks a lot.
~15% slowdown for FP intensive code. I would like to point on similar
problem with FP compares
The patch for PR17767 also fixes your testcase for PR18944:
Now i'd also like to point to SSE & FP compares but i'm unsure
http://gcc.gnu.org/ml/gcc-patches/2005-01/msg00168.html address that
too (as far as i grok it, it deals with NaNs an issue i had to
struggle with and triggered
gcc -O2 -msse2 -mfpmath=sse pr18944.c
movl %esp, %ebp
subl $24, %esp
movss .LC0, %xmm0
andl $-16, %esp
subl $16, %esp
divss .LC1, %xmm0
movss %xmm0, -4(%ebp)
movss -4(%ebp), %xmm0
shufps $0, %xmm0, %xmm0
cmpunordps %xmm0, %xmm0
However, I don't know what kind of joy gcc gets from moving %xmm0 to
memory and back before shufps insn.
Case in point:Hm, yes, I think this is another case of TARGET_SSE_MATH problems.
[snip lots of SSE only operations]
401535: movss %xmm2,0xc(%esp)
40153b: flds 0xc(%esp)
40153f: fcomip %st(1),%st
401541: jbe 401650
Feel free to clue me :)