backport: re PR middle-end/89008 (O2 and O1 results differ for simple test)

2019-01-24  Richard Biener  <rguenther@suse.de>

	Backport from mainline
	2019-01-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/89008
	* tree-ssa-reassoc.c (eliminate_using_constants): For * 0 do
	not leave another stray operand.

	* gcc.dg/torture/pr89008.c: New testcase.

From-SVN: r268235

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e8473b0d799bb2b5b1172746efb914644e52dd84..5be5bab18c643d9ef3cd25d7344221d796d7cb9f 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2019-01-24  Richard Biener  <rguenther@suse.de>
+
+       Backport from mainline
+       2019-01-23  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/89008
+       * tree-ssa-reassoc.c (eliminate_using_constants): For * 0 do
+       not leave another stray operand.
+
 2019-01-22  Uroš Bizjak  <ubizjak@gmail.com>
 
        PR target/88938

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5a2ad99ffab5402dcbd57264ca404c7c9d4ffb7a..1c5f79aadd9b746dcbd109cc88173a2dd53ca416 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2019-01-24  Richard Biener  <rguenther@suse.de>
+
+       Backport from mainline
+       2019-01-23  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/89008
+       * gcc.dg/torture/pr89008.c: New testcase.
+
 2019-01-22  Uroš Bizjak  <ubizjak@gmail.com>
 
        PR target/88938

diff --git a/gcc/testsuite/gcc.dg/torture/pr89008.c b/gcc/testsuite/gcc.dg/torture/pr89008.c
new file mode 100644 (file)
index 0000000..aa13f94
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr89008.c
@@ -0,0 +1,27 @@
+/* { dg-do run } */
+/* { dg-require-effective-target int32plus } */
+
+unsigned long a, c;
+unsigned b;
+int d, e;
+long f()
+{
+  unsigned long g = 0;
+  for (d = 0; d < 5; d += 2)
+    for (e = 0; e < 5; e += 3)
+      {
+       c = 4 + b;
+       g = -b - b;
+       b = 5 * (b << 24);
+      }
+  a = g;
+  return 0;
+}
+
+int main()
+{
+  f();
+  if (a)
+    __builtin_abort();
+  return 0;
+}

diff --git a/gcc/tree-ssa-reassoc.c b/gcc/tree-ssa-reassoc.c
index e6562c6c9ba1c4b295582bcd61059eced2947a5b..b4f13ef75c4da48072588f61f36f177f1141151d 100644 (file)
--- a/gcc/tree-ssa-reassoc.c
+++ b/gcc/tree-ssa-reassoc.c
@@ -1012,7 +1012,7 @@ eliminate_using_constants (enum tree_code opcode,
                    fprintf (dump_file, "Found * 0, removing all other ops\n");
 
                  reassociate_stats.ops_eliminated += ops->length () - 1;
-                 ops->truncate (1);
+                 ops->truncate (0);
                  ops->quick_push (oelast);
                  return;
                }