https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79450
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2017-02-10
CC| |jakub at gcc dot gnu.org,
| |segher at gcc dot gnu.org
Ever confirmed|0 |1
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r176984, but likely that just uncovered a latent RTL optimization
bug, because the only difference in *.optimized with that is swapping of
operands in a single stmt:
--- pr79450.c.143t.optimized_ 2017-02-10 03:58:22.000000000 -0500
+++ pr79450.c.143t.optimized 2017-02-10 03:58:48.000000000 -0500
@@ -20,7 +20,7 @@ foo (u8 p1, u64 p2)
D.2710_4 = p2_3(D) == 0;
D.2711_5 = (signed char) D.2710_4;
p1.0_6 = (signed char) p1_1;
- D.2713_7 = p1.0_6 & D.2711_5;
+ D.2713_7 = D.2711_5 & p1.0_6;
p1_8 = (u8) D.2713_7;
p1_9 = p1_8 % 24;
D.2714_10 = (u64) p1_9;
The resulting asm change is:
--- pr79450.s_ 2017-02-10 03:58:22.000000000 -0500
+++ pr79450.s 2017-02-10 03:58:48.000000000 -0500
@@ -12,8 +12,7 @@ foo:
movzbl %dil, %eax
cmpq %rax, %rsi
ja .L2
- movzbl %dil, %edi
- leal (%rdi,%rsi), %eax
+ movl %esi, %eax
ret
.cfi_endproc
.LFE0:
though.
Things go wrong during combine.
