https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108419
Bug ID: 108419
Summary: [13 Regression] Dead Code Elimination Regression at
-O2 since r13-440-g98e475a8f58
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: yann at ywg dot ch
Target Milestone: ---
Created attachment 54281
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54281&action=edit
case as file
cat case.c #1565
static int b = 6, c;
long d;
short h;
short i;
short j;
char k;
void foo();
short(a)(short l, short m) { return l + m; }
short f();
short g(unsigned short, int, char, long);
static signed char e() {
unsigned n = -10;
for (; n >= 14; n = a(n, 8)) {
i = g(b, 0, c, b);
j = f(i, b, d < j, 5, 7, 9, 5);
k = 200 + n;
h = k % 5;
if (h)
;
else
foo();
}
return n;
}
int main() {
b || e();
b = 1;
}
`gcc-f99d7d669eaa2830eb5878df4da67e77ec791522 (trunk) -O2` can not eliminate
`foo` but `gcc-releases/gcc-12.2.0 -O2` can.
`gcc-f99d7d669eaa2830eb5878df4da67e77ec791522 (trunk) -O2 -S -o /dev/stdout
case.c`
--------- OUTPUT ---------
main:
.LFB2:
.cfi_startproc
movl b(%rip), %esi
testl %esi, %esi
je .L12
movl $1, b(%rip)
xorl %eax, %eax
ret
.L12:
pushq %r12
.cfi_def_cfa_offset 16
.cfi_offset 12, -16
movl $-10, %r12d
pushq %rbp
.cfi_def_cfa_offset 24
.cfi_offset 6, -24
movl $2, %ebp
pushq %rbx
.cfi_def_cfa_offset 32
.cfi_offset 3, -32
movl $5, %ebx
.L6:
movslq b(%rip), %rcx
xorl %edx, %edx
xorl %esi, %esi
movzwl %cx, %edi
call g
movl b(%rip), %esi
movl $5, %ecx
movswq j(%rip), %rdx
movw %ax, i(%rip)
cmpq d(%rip), %rdx
movswl %ax, %edi
movl $9, %r9d
pushq %rax
.cfi_def_cfa_offset 40
setg %dl
movl $7, %r8d
xorl %eax, %eax
pushq $5
.cfi_def_cfa_offset 48
movzbl %dl, %edx
call f
movw %ax, j(%rip)
leal -56(%r12), %eax
movb %al, k(%rip)
cbtw
idivb %bl
movl %eax, %edx
sarw $8, %dx
shrw $8, %ax
movw %dx, h(%rip)
popq %rdx
.cfi_def_cfa_offset 40
popq %rcx
.cfi_def_cfa_offset 32
je .L13
.L5:
addl $8, %r12d
subl $1, %ebp
movswl %r12w, %r12d
je .L14
movl $1, %ebp
jmp .L6
.L14:
movl $1, b(%rip)
popq %rbx
.cfi_remember_state
.cfi_def_cfa_offset 24
xorl %eax, %eax
popq %rbp
.cfi_def_cfa_offset 16
popq %r12
.cfi_def_cfa_offset 8
ret
.L13:
.cfi_restore_state
xorl %eax, %eax
call foo
jmp .L5
---------- END OUTPUT ---------
`gcc-releases/gcc-12.2.0 -O2 -S -o /dev/stdout case.c`
--------- OUTPUT ---------
main:
.LFB2:
.cfi_startproc
movl b(%rip), %r9d
testl %r9d, %r9d
je .L11
movl $1, b(%rip)
xorl %eax, %eax
ret
.L11:
pushq %rbp
.cfi_def_cfa_offset 16
.cfi_offset 6, -16
movl $-66, %ebp
pushq %rbx
.cfi_def_cfa_offset 24
.cfi_offset 3, -24
movl $5, %ebx
pushq %r8
.cfi_def_cfa_offset 32
.L5:
movslq b(%rip), %rcx
xorl %edx, %edx
xorl %esi, %esi
movzwl %cx, %edi
call g
movswq j(%rip), %rdx
cmpq d(%rip), %rdx
movl $9, %r9d
pushq %rcx
.cfi_def_cfa_offset 40
setg %dl
movl b(%rip), %esi
movswl %ax, %edi
pushq $5
.cfi_def_cfa_offset 48
movzbl %dl, %edx
movl $7, %r8d
movl $5, %ecx
movw %ax, i(%rip)
xorl %eax, %eax
call f
popq %rsi
.cfi_def_cfa_offset 40
popq %rdi
.cfi_def_cfa_offset 32
movb %bpl, k(%rip)
movw %ax, j(%rip)
movsbw %bpl, %ax
idivb %bl
sarw $8, %ax
movw %ax, h(%rip)
cmpb $-58, %bpl
je .L12
movl $-58, %ebp
jmp .L5
.L12:
movl $1, b(%rip)
xorl %eax, %eax
popq %rdx
.cfi_def_cfa_offset 24
popq %rbx
.cfi_def_cfa_offset 16
popq %rbp
.cfi_def_cfa_offset 8
ret
---------- END OUTPUT ---------
Bisects to: r13-440-g98e475a8f58
commit 98e475a8f58ca3ba6e9bd5c9276efce4236f5d26
Author: Andrew MacLeod <[email protected]>
Date: Fri Mar 18 11:50:33 2022 -0400
Fix return value in ranger_cache::get_global_range.
The "is_current" status is returned by parameter, but was being returned by
the
function as well instead of true if NAME had a global range, and FALSE
if it did not.
* gimple-range-cache.cc (ranger_cache::get_global_range): Return
the
had_global value instead.
