We cant represent ADDR_EXPR in ranges, so when we are processing
builtin_unreachable() we should not be removing comparisons that utilize
ADDR_EXPR during the early phases, or we lose some important information.
It was just an oversight that we think its a comparison to a
representable constant.
Bootstrapped on x86_64-pc-linux-gnu with no regressions. pushed.
This would also be suitable for the next GCC13 release when the branch
is open.
Andrew
commit 0afefd11e25a05dd4f8a8624e8fb046d9c85686a
Author: Andrew MacLeod <amacl...@redhat.com>
Date: Fri Apr 21 15:03:43 2023 -0400
Do not fold ADDR_EXPR conditions leading to builtin_unreachable early.
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.
diff --git a/gcc/testsuite/gcc.dg/pr109546.c b/gcc/testsuite/gcc.dg/pr109546.c
new file mode 100644
index 00000000000..ba8af0f31fa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr109546.c
@@ -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" } } */
+
+
diff --git a/gcc/tree-vrp.cc b/gcc/tree-vrp.cc
index f4d484526c7..9b870640e23 100644
--- a/gcc/tree-vrp.cc
+++ b/gcc/tree-vrp.cc
@@ -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)
{
