re PR tree-optimization/87087 (Optimization hangs up and consumes over 15Gb of memory)

2018-10-18  Richard Biener  <rguenther@suse.de>

	PR middle-end/87087
	Revert
	2018-02-07  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/84204
        * tree-chrec.c (chrec_fold_plus_1): Remove size limiting in
        this place.

	* gcc.dg/torture/pr87087.c: New testcase.
	* gcc.dg/graphite/pr84204.c: XFAIL.
	* gcc.dg/graphite/pr85935.c: Likewise.

From-SVN: r265261

gcc/ChangeLog

+2018-10-18  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/87087
+	Revert
+	2018-02-07  Richard Biener  <rguenther@suse.de>
+
+        PR tree-optimization/84204
+        * tree-chrec.c (chrec_fold_plus_1): Remove size limiting in
+        this place.
+
 2018-10-18  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/87537

gcc/testsuite/ChangeLog

+2018-10-18  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/87087
+	* gcc.dg/torture/pr87087.c: New testcase.
+	* gcc.dg/graphite/pr84204.c: XFAIL.
+	* gcc.dg/graphite/pr85935.c: Likewise.
+
 2018-10-18  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/87537

gcc/testsuite/gcc.dg/graphite/pr84204.c

 /* { dg-do compile } */
 /* { dg-options "-O -floop-parallelize-all -fno-tree-loop-im --param scev-max-expr-size=3" } */
+/* The fix for PR84204 was reverted.  */
+/* { dg-additional-options "--param graphite-allow-codegen-errors=1" } */
 
 int oc;
 

gcc/testsuite/gcc.dg/graphite/pr85935.c

 /* { dg-do compile } */
 /* { dg-options "-O -floop-parallelize-all -fno-tree-loop-im --param scev-max-expr-size=3" } */
+/* The fix for PR84204 was reverted.  */
+/* { dg-additional-options "--param graphite-allow-codegen-errors=1" } */
 
 typedef int dq;
 

gcc/testsuite/gcc.dg/torture/pr87087.c

+/* { dg-do compile } */
+/* { dg-require-effective-target int32plus } */
+
+int b;
+int d;
+void e()
+{
+  unsigned f;
+  unsigned g;
+  int h;
+  long i = 901380;
+  for (;;) {
+      d = 0;
+      for (; d; d++) {
+	  h = 143366620;
+	  f = 0;
+	  for (; f < 15; f += 3) {
+	      g = 0;
+	      for (; g < 9; g++)
+		b = h = i - (h << 5) + h;
+	  }
+      }
+      i = 0;
+  }
+}

gcc/tree-chrec.c

@@ -328,10 +328,12 @@ chrec_fold_plus_1 (enum tree_code code, tree type,
 
 	default:
 	  {
-	    if (tree_contains_chrecs (op0, NULL)
-		|| tree_contains_chrecs (op1, NULL))
+	    int size = 0;
+	    if ((tree_contains_chrecs (op0, &size)
+		 || tree_contains_chrecs (op1, &size))
+		&& size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE))
 	      return build2 (code, type, op0, op1);
-	    else
+	    else if (size < PARAM_VALUE (PARAM_SCEV_MAX_EXPR_SIZE))
 	      {
 		if (code == POINTER_PLUS_EXPR)
 		  return fold_build_pointer_plus (fold_convert (type, op0),
@@ -341,6 +343,8 @@ chrec_fold_plus_1 (enum tree_code code, tree type,
 				      fold_convert (type, op0),
 				      fold_convert (type, op1));
 	      }
+	    else
+	      return chrec_dont_know;
 	  }
 	}
     }