This is the mail archive of the
gcc-bugs@gcc.gnu.org
mailing list for the GCC project.
[Bug tree-optimization/79390] 10% performance drop in SciMark2 LU after r242550
- From: "ubizjak at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 24 Feb 2017 13:25:21 +0000
- Subject: [Bug tree-optimization/79390] 10% performance drop in SciMark2 LU after r242550
- Auto-submitted: auto-generated
- References: <bug-79390-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79390
--- Comment #7 from Uroš Bizjak <ubizjak at gmail dot com> ---
The testcase for RTL if-conversion part:
--cut here--
extern double A[32];
int foo (void)
{
double t = A[0];
int jp = 0;
int i;
for (i = 0; i < 32; i++)
{
double ab = A[i];
if (ab > t)
{
jp = i;
t = ab;
}
}
return jp;
}
--cut here--
gcc -O2:
...
.L5:
movsd A(,%rdx,8), %xmm0
ucomisd %xmm1, %xmm0
jbe .L3
movapd %xmm0, %xmm1
movl %edx, %eax
.L3:
addq $1, %rdx
.L2:
cmpq $32, %rdx
jne .L5
There is no difference w/ and w/o -fno-split-paths with the above testcase.