https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110919
Bug ID: 110919
Summary: [14 Regression] Dead Code Elimination Regression at
-O3 since r14-1691-gbc5a2c2e793
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: scherrer.sv at gmail dot com
Target Milestone: ---
static short a, b;
static int e;
static int *j = &e;
void bar151_(void);
void foo(void);
void bar162_(void);
static int(d)(int k, int l) { return l == k && l - 1 ? k : 0; }
static void f();
static void g(unsigned short, unsigned);
static void h() {
g(0, 4);
f();
int i = -1;
g(0, i);
}
static void f(int k) { g(k, 0); }
static void g(unsigned short k, unsigned l) {
if (k)
bar151_();
if (l)
if (k)
bar162_();
short c = l;
b = c == 0 || a;
if (d(*j, b))
foo();
}
int main() { h(); }
gcc-87b0749cfb9 (trunk) -O3 cannot eliminate the call to foo but
gcc-releases/gcc-13.1.0 -O3 can.
-----------------------------------------------------------------------
gcc-87b0749cfb9406790b108208b466cf507ae3c431 -O3 case.c -S -o case.s
--------- OUTPUT ---------
main:
.LFB4:
.cfi_startproc
subq $8, %rsp
.cfi_def_cfa_offset 16
movl $4, %esi
xorl %edi, %edi
call g
xorl %esi, %esi
xorl %edi, %edi
call g
movl $-1, %esi
xorl %edi, %edi
call g
xorl %eax, %eax
addq $8, %rsp
.cfi_def_cfa_offset 8
ret
---------- END OUTPUT ---------
-----------------------------------------------------------------------
gcc-2b98cc24d6af0432a74f6dad1c722ce21c1f7458 -O3 case.c -S -o case.s
--------- OUTPUT ---------
main:
.LFB4:
.cfi_startproc
subq $8, %rsp
.cfi_def_cfa_offset 16
movl $4, %esi
xorl %edi, %edi
call g
xorl %esi, %esi
xorl %edi, %edi
call g
movl $-1, %esi
xorl %edi, %edi
call g
xorl %eax, %eax
addq $8, %rsp
.cfi_def_cfa_offset 8
ret
---------- END OUTPUT ---------
-----------------------------------------------------------------------
Bisects to r14-1691-gbc5a2c2e793
