https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95526
Bug ID: 95526
Summary: aarch64: Wrong code accessing complex number from
varargs
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: acoplan at gcc dot gnu.org
Target Milestone: ---
Commit eb72dc663e9070b281be83a80f6f838a3a878822 introduces a wrong code bug on
AArch64.
This causes the test case gcc/testsuite/gcc.dg/complex-1.c to start failing.
This test case can be reduced to the following program:
extern void abort(void);
void f(unsigned x, ...)
{
__builtin_va_list ap;
_Complex float cf;
__builtin_va_start(ap, x);
cf = __builtin_va_arg(ap, _Complex float);
__builtin_va_end(ap);
if (__imag__ cf != 2.0f)
abort();
}
int main(void)
{
f(0, 2.0fi);
}
which calls abort() at both -O0 and -O2 after this patch. Prior to this patch,
we get the following code for f at -O2:
f:
.LFB0:
.cfi_startproc
stp x29, x30, [sp, -80]!
.cfi_def_cfa_offset 80
.cfi_offset 29, -80
.cfi_offset 30, -72
mov x29, sp
str q1, [sp, 64]
fmov s1, 2.0e+0
add x0, sp, 80
ldr s2, [sp, 64]
stp x0, x0, [sp, 16]
fcmp s2, s1
str x0, [sp, 32]
stp wzr, wzr, [sp, 40]
str q0, [sp, 48]
bne .L8
ldp x29, x30, [sp], 80
.cfi_remember_state
.cfi_restore 30
.cfi_restore 29
.cfi_def_cfa_offset 0
ret
.L8:
.cfi_restore_state
bl abort
.cfi_endproc
and now, we get:
f:
.LFB0:
.cfi_startproc
stp x29, x30, [sp, -80]!
.cfi_def_cfa_offset 80
.cfi_offset 29, -80
.cfi_offset 30, -72
mov w0, -32
add x1, sp, 80
mov x29, sp
stp x1, x1, [sp, 16]
str x1, [sp, 32]
stp wzr, w0, [sp, 40]
str q0, [sp, 48]
str q1, [sp, 64]
bl abort
.cfi_endproc
which appears to unconditionally call abort().
