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Do not fold ADDR_EXPR conditions leading to builtin_unreachable early.

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Ranges can not represent &var globally yet, so we cannot fold these
expressions early or we lose the __builtin_unreachable information.

	PR tree-optimization/109546
	gcc/
	* tree-vrp.cc (remove_unreachable::remove_and_update_globals): Do
	not fold conditions with ADDR_EXPR early.

	gcc/testsuite/
	* gcc.dg/pr109546.c: New.
This commit is contained in:
Andrew MacLeod 2023-04-21 15:03:43 -04:00
parent 03cebd3049
commit f828503eeb
2 changed files with 27 additions and 1 deletions
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24
gcc/testsuite/gcc.dg/pr109546.c Normal file
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@ -0,0 +1,24 @@
/* { dg-do compile } */
/* { dg-options "-O3 -fdump-tree-optimized" } */
void foo(void);
static int a, c;
static int *b = &a;
static int **d = &b;
void assert_fail() __attribute__((__noreturn__));
int main() {
int *e = *d;
if (e == &a || e == &c);
else {
__builtin_unreachable();
assert_fail();
}
if (e == &a || e == &c);
else
foo();
}
/* { dg-final { scan-tree-dump-not "assert_fail" "optimized" } } */
/* { dg-final { scan-tree-dump-not "foo" "optimized" } } */

4
gcc/tree-vrp.cc
View file

@ -150,7 +150,9 @@ remove_unreachable::remove_and_update_globals (bool final_p)
// If this is already a constant condition, don't look either
if (!lhs_p && !rhs_p)
continue;
// Do not remove addresses early. ie if (x == &y)
if (!final_p && lhs_p && TREE_CODE (gimple_cond_rhs (s)) == ADDR_EXPR)
continue;
bool dominate_exit_p = true;
FOR_EACH_GORI_EXPORT_NAME (m_ranger.gori (), e->src, name)
{