https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85095
Bug ID: 85095
Summary: [6/7/8 Regression] worse code generated
Product: gcc
Version: 8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ipa
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
CC: hubicka at gcc dot gnu.org, marxin at gcc dot gnu.org
Target Milestone: ---
typedef unsigned long uint64_t;
uint64_t adc(uint64_t a, uint64_t b)
{
a += b;
if (a < b) /* should simplify to nothing (setting carry is implicit in the
add) */
a++; /* should simplify to adc r0, 0 */
return a;
}
At r230856 with -O3 this gets compiled to:
movq %rdi, %rax # a, a
addq %rsi, %rax # b, a
adcq $0, %rax #, <retval>
ret
At r230857 it becomes:
xorl %eax, %eax # _7
addq %rdi, %rsi # a, tmp93
setc %al #, _7
cmpq $1, %rax #, _7
movq %rsi, %rax # tmp93, tmp93
sbbq $-1, %rax #, tmp93
ret
commit 83caf9ff7e5307a3982af5efe4885524b0be0d88
Author: hubicka <hubicka@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Wed Nov 25 09:08:20 2015 +0000
* ipa-inline-analysis.c: Include gimplify.h
(set_cond_stmt_execution_predicate,
set_switch_stmt_execution_predicate): Be sure to not leak locations
to function body.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230857
138bc75d-0d04-0410-961f-82ee72b054a4
