https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65783
Bug ID: 65783
Summary: after reload, the memrefs_conflict_p is unreliable?
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: wangjiefeng at huawei dot com
int f = -1;
int foo(int * pa)
{
int a = 1;
*(pa) = a;
pa = pa + f;
a = *(pa + 1);
return a;
}
With -O2, the ARM's assembler is as follows:
foo:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
movw r3, #:lower16:.LANCHOR0 @ 20 *arm_movsi_insn/4 [length
= 4]
mov r2, #1 @ 6 *arm_movsi_insn/2 [length = 4]
movt r3, #:upper16:.LANCHOR0 @ 21 *arm_movt [length = 4]
str r2, [r0] @ 7 *arm_movsi_insn/6 [length = 4]
ldr r3, [r3] @ 9 *arm_movsi_insn/5 [length = 4]
add r0, r0, r3, asl #2 @ 11 *arith_shiftsi/1 [length
= 4]
ldr r0, [r0, #4] @ 17 *arm_movsi_insn/5 [length = 4]
bx lr @ 26 *arm_return [length = 12]
.size foo, .-foo
.global f
.data
.align 2
In sched1, insn 7 and insn 17 has true dependence, but in sched2, the true
dependence between insn 7 and insn 17 is omitted.
It seems after reload, in function true_dependence_1, the memrefs_conflict_p is
unreliable?
