re PR tree-optimization/87700 (Compile time hog w/ -O1)

2018-10-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87700
	* tree-ssa-copy.c (set_copy_of_val): Fix change detection logic.

	* gcc.dg/torture/pr87700.c: New testcase.

From-SVN: r265418

gcc/ChangeLog

+2018-10-23  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/87700
+	* tree-ssa-copy.c (set_copy_of_val): Fix change detection logic.
+
 2018-10-23  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/87674

gcc/testsuite/ChangeLog

 2018-10-23  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/87700
+	* gcc.dg/torture/pr87700.c: New testcase.
+
+2018-10-23  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/87693
 	* gcc.dg/torture/pr87693.c: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr87700.c

+/* { dg-do compile } */
+
+void
+wn (int ki)
+{
+  int m8 = 0;
+  int *d6 = &ki;
+
+  if (ki == 0)
+    {
+ud:
+      for (ki = 0; ki < 1; ++ki)
+	for (m8 = 0; m8 < 1; ++m8)
+	  goto ud;
+
+      d6 = &m8;
+
+y8:
+      ++m8;
+
+xw:
+      if (ki == 0)
+	{
+	}
+      else
+	{
+	  for (m8 = 0; m8 < 1; ++m8)
+	    {
+gt:
+	      if (*d6 == 0)
+		goto y8;
+	    }
+
+	  for (m8 = 0; m8 < 1; ++m8)
+	    {
+	      goto gt;
+
+ym:
+	      ;
+	    }
+	}
+
+      d6 = &ki;
+
+      goto ym;
+    }
+
+  goto xw;
+}

gcc/tree-ssa-copy.c

@@ -155,7 +155,7 @@ set_copy_of_val (tree var, tree val)
   copy_of[ver].value = val;
 
   if (old != val
-      || (val && !operand_equal_p (old, val, 0)))
+      && (!old || !operand_equal_p (old, val, 0)))
     return true;
 
   return false;