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[Bug rtl-optimization/70478] New: [LRA] S/390: Performance regression - superfluous stack frame
- From: "krebbel at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 31 Mar 2016 11:18:18 +0000
- Subject: [Bug rtl-optimization/70478] New: [LRA] S/390: Performance regression - superfluous stack frame
- Auto-submitted: auto-generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70478
Bug ID: 70478
Summary: [LRA] S/390: Performance regression - superfluous
stack frame
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: krebbel at gcc dot gnu.org
Target Milestone: ---
void foo(unsigned int *a, unsigned char *b)
{
*a &= *b;
}
cc1 -O3 -march=z9-109 t.c -mno-lra
foo:
llc %r1,0(%r3)
n %r1,0(%r2)
st %r1,0(%r2)
br %r14
cc1 -O3 -march=z9-109 t.c
foo:
stg %r15,120(%r15)
lay %r15,-168(%r15)
llc %r1,0(%r3)
st %r1,164(%r15)
nc 0(4,%r2),164(%r15)
lg %r15,288(%r15)
br %r14
Problem is present since r199754 which enabled LRA on S/390.