From: Lewis Hyatt <lhyatt@gmail.com>
Date: Thu, 26 Dec 2024 15:58:57 +0000 (-0500)
Subject: tree-optimization: Fix ICE in tree-parloops.cc reduction_phi() [PR118205]
X-Git-Tag: basepoints/gcc-16~3091
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=83e291014fff0b3ce1baedf59292390726d67335;p=thirdparty%2Fgcc.git

tree-optimization: Fix ICE in tree-parloops.cc reduction_phi() [PR118205]

Prior to r15-6001, reduction_phi() could be called with the PHI parameter
not actually being a gphi*. The search through reduction_list would fail and
return NULL. r15-6001 added a requirement that PHI actually be a gphi*, but
did not add a check for this. The PR shows an example where the check is
needed; fix by explicitly returning NULL in this case.

gcc/ChangeLog:

	PR tree-optimization/118205
	* tree-parloops.cc (reduction_phi): Return NULL if PHI parameter is
	not a phi node.

gcc/testsuite/ChangeLog:

	PR tree-optimization/118205
	* c-c++-common/pr118205.c: New test.
---

diff --git a/gcc/testsuite/c-c++-common/pr118205.c b/gcc/testsuite/c-c++-common/pr118205.c
new file mode 100644
index 000000000000..c98f8d84a1b5
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr118205.c
@@ -0,0 +1,25 @@
+/* PR tree-optimization/118205 */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target fgraphite } */
+/* { dg-require-effective-target pthread } */
+/* { dg-options "-O -floop-parallelize-all -ftree-parallelize-loops=2" } */
+
+int x;
+void g(int);
+int f() {
+  unsigned res = 0;
+  int arr[] = {};
+  int y = 0;
+  for (unsigned int i = 1; i; i++)
+    {
+      for (int n = 0; n < 2; n++)
+	{
+	  g(arr[i]);
+	  res = y > x ? y : x;
+	  y = res;
+        }
+      g(arr[i]);
+    }
+  return res;
+}
diff --git a/gcc/tree-parloops.cc b/gcc/tree-parloops.cc
index 8427c287a6a7..421832973994 100644
--- a/gcc/tree-parloops.cc
+++ b/gcc/tree-parloops.cc
@@ -948,7 +948,7 @@ reduction_phi (reduction_info_table_type *reduction_list, gimple *phi)
 {
   struct reduction_info tmpred, *red;
 
-  if (reduction_list->is_empty () || phi == NULL)
+  if (reduction_list->is_empty () || phi == NULL || !is_a <gphi *> (phi))
     return NULL;
 
   if (gimple_uid (phi) == (unsigned int)-1