[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511
--- Comment #7 from Peter Cordes ---
I'm seeing the same symptom, affecting gcc4.9 through 5.3. Not present in 6.1.
IDK if the cause is the same.
(code from an improvement to the horizontal_add functions in Agner Fog's vector
class library)
#include
int hsum16_gccmovdqa (__m128i const a) {
__m128i lo= _mm_cvtepi16_epi32(a); // sign-extended
a0, a1, a2, a3
__m128i hi= _mm_unpackhi_epi64(a,a); // gcc4.9 through 5.3
wastes a movdqa on this
hi= _mm_cvtepi16_epi32(hi);
__m128i sum1 = _mm_add_epi32(lo,hi); // add
sign-extended upper / lower halves
//return horizontal_add(sum1); // manually inlined.
// Shortening the code below can avoid the movdqa
__m128i shuf = _mm_shuffle_epi32(sum1, 0xEE);
__m128i sum2 = _mm_add_epi32(shuf,sum1); // 2 sums
shuf = _mm_shufflelo_epi16(sum2, 0xEE);
__m128i sum4 = _mm_add_epi32(shuf,sum2);
return _mm_cvtsi128_si32(sum4); // 32 bit sum
}
gcc4.9 through gcc5.3 output (-O3 -mtune=generic -msse4.1):
movdqa %xmm0, %xmm1
pmovsxwd%xmm0, %xmm2
punpckhqdq %xmm0, %xmm1
pmovsxwd%xmm1, %xmm0
paddd %xmm2, %xmm0
...
gcc6.1 output:
pmovsxwd%xmm0, %xmm1
punpckhqdq %xmm0, %xmm0
pmovsxwd%xmm0, %xmm0
paddd %xmm0, %xmm1
...
In a more complicated case, when inlining this code or not, there's actually a
difference between gcc 4.9 and 5.x: gcc5 has the extra movdqa in more cases.
See my attachment, copied from https://godbolt.org/g/e8iQsj
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 Peter Cordes changed: What|Removed |Added CC||peter at cordes dot ca --- Comment #6 from Peter Cordes --- Created attachment 38629 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38629=edit extra-movdqa-with-gcc5-not-4.9.cpp
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 --- Comment #4 from Vladimir Makarov vmakarov at gcc dot gnu.org --- Author: vmakarov Date: Wed Jan 15 17:32:47 2014 New Revision: 206636 URL: http://gcc.gnu.org/viewcvs?rev=206636root=gccview=rev Log: 2014-01-15 Vladimir Makarov vmaka...@redhat.com PR rtl-optimization/59511 * ira.c (ira_init_register_move_cost): Use memory costs for some cases of register move cost calculations. * lra-constraints.c (lra_constraints): Use REG_FREQ_FROM_BB instead of BB frequency. * lra-coalesce.c (move_freq_compare_func, lra_coalesce): Ditto. * lra-assigns.c (find_hard_regno_for): Ditto. Modified: trunk/gcc/ChangeLog trunk/gcc/ira.c trunk/gcc/lra-assigns.c trunk/gcc/lra-coalesce.c trunk/gcc/lra-constraints.c
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 Jakub Jelinek jakub at gcc dot gnu.org changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |FIXED --- Comment #5 from Jakub Jelinek jakub at gcc dot gnu.org --- Fixed, thanks.
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 Richard Biener rguenth at gcc dot gnu.org changed: What|Removed |Added Priority|P3 |P1
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 --- Comment #3 from Vladimir Makarov vmakarov at gcc dot gnu.org --- (In reply to Jakub Jelinek from comment #2) One movdqa started appearing with r204212, the second movdqa started appearing with r204752. Vlad, can you please have a look? It seems the changes triggered a bug in register move cost calculations. I have a patch to fix it but I need more time to check affect of it on the performance. So the fix will be ready at the end of week if everything is ok.
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 Jakub Jelinek jakub at gcc dot gnu.org changed: What|Removed |Added CC||jakub at gcc dot gnu.org --- Comment #2 from Jakub Jelinek jakub at gcc dot gnu.org --- One movdqa started appearing with r204212, the second movdqa started appearing with r204752. Vlad, can you please have a look?
[Bug rtl-optimization/59511] [4.9 Regression] FAIL: gcc.target/i386/pr36222-1.c scan-assembler-not movdqa with -mtune=corei7
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59511 Uroš Bizjak ubizjak at gmail dot com changed: What|Removed |Added Keywords||ra Target||x86_64-pc-linux-gnu Status|UNCONFIRMED |NEW Last reconfirmed||2013-12-15 CC||vmakarov at gcc dot gnu.org Target Milestone|--- |4.9.0 Ever confirmed|0 |1 --- Comment #1 from Uroš Bizjak ubizjak at gmail dot com --- Confirmed as RA regression.
