From: Andrew MacLeod <amacleod@redhat.com>
Date: Fri, 21 Apr 2023 19:03:43 +0000 (-0400)
Subject: Do not fold ADDR_EXPR conditions leading to builtin_unreachable early.
X-Git-Tag: basepoints/gcc-15~9979
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f828503eeb79ad1f1ada6db7deccc5abcc2f3ca3;p=thirdparty%2Fgcc.git

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 000000000000..ba8af0f31fa6
--- /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 f4d484526c77..9b870640e238 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)
 	{