[PATCH] Fix PR77920

Richard Biener rguenther@suse.de
Wed Oct 12 07:04:00 GMT 2016


VRP needs to make sure to update the iterator it gets to it stmt folding
callback.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2016-10-12  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/77920
	* tree-vrp.c (simplify_div_or_mod_using_ranges): Simplify.
	(simplify_min_or_max_using_ranges): Pass in gsi and use it.
	(simplify_abs_using_ranges): Likewise.
	(simplify_conversion_using_ranges): Likewise.
	(simplify_stmt_using_ranges): Adjust.

	* gcc.dg/torture/pr77920.c: New testcase.

Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c	(revision 240964)
+++ gcc/tree-vrp.c	(working copy)
@@ -9093,9 +9093,7 @@ simplify_div_or_mod_using_ranges (gimple
 	{
 	  /* If op0 already has the range op0 % op1 has,
 	     then TRUNC_MOD_EXPR won't change anything.  */
-	  gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
-	  gimple_assign_set_rhs_from_tree (&gsi, op0);
-	  update_stmt (stmt);
+	  gimple_assign_set_rhs_from_tree (gsi, op0);
 	  return true;
 	}
     }
@@ -9171,7 +9169,7 @@ simplify_div_or_mod_using_ranges (gimple
    disjoint.   Return true if we do simplify.  */
 
 static bool
-simplify_min_or_max_using_ranges (gimple *stmt)
+simplify_min_or_max_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt)
 {
   tree op0 = gimple_assign_rhs1 (stmt);
   tree op1 = gimple_assign_rhs2 (stmt);
@@ -9206,10 +9204,7 @@ simplify_min_or_max_using_ranges (gimple
 	 VAL == FALSE -> OP0 > or >= op1.  */
       tree res = ((gimple_assign_rhs_code (stmt) == MAX_EXPR)
 		  == integer_zerop (val)) ? op0 : op1;
-      gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
-      gimple_assign_set_rhs_from_tree (&gsi, res);
-      update_stmt (stmt);
-      fold_stmt (&gsi, follow_single_use_edges);
+      gimple_assign_set_rhs_from_tree (gsi, res);
       return true;
     }
 
@@ -9221,7 +9216,7 @@ simplify_min_or_max_using_ranges (gimple
    ABS_EXPR into a NEGATE_EXPR.  */
 
 static bool
-simplify_abs_using_ranges (gimple *stmt)
+simplify_abs_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt)
 {
   tree op = gimple_assign_rhs1 (stmt);
   value_range *vr = get_value_range (op);
@@ -9262,8 +9257,7 @@ simplify_abs_using_ranges (gimple *stmt)
 	  else
 	    gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
 	  update_stmt (stmt);
-	  gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
-	  fold_stmt (&gsi, follow_single_use_edges);
+	  fold_stmt (gsi, follow_single_use_edges);
 	  return true;
 	}
     }
@@ -9844,7 +9838,7 @@ simplify_switch_using_ranges (gswitch *s
 /* Simplify an integral conversion from an SSA name in STMT.  */
 
 static bool
-simplify_conversion_using_ranges (gimple *stmt)
+simplify_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple *stmt)
 {
   tree innerop, middleop, finaltype;
   gimple *def_stmt;
@@ -9914,8 +9908,7 @@ simplify_conversion_using_ranges (gimple
     return false;
 
   gimple_assign_set_rhs1 (stmt, innerop);
-  gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
-  fold_stmt (&gsi, follow_single_use_edges);
+  fold_stmt (gsi, follow_single_use_edges);
   return true;
 }
 
@@ -10218,7 +10211,7 @@ simplify_stmt_using_ranges (gimple_stmt_
 	case ABS_EXPR:
 	  if (TREE_CODE (rhs1) == SSA_NAME
 	      && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
-	    return simplify_abs_using_ranges (stmt);
+	    return simplify_abs_using_ranges (gsi, stmt);
 	  break;
 
 	case BIT_AND_EXPR:
@@ -10233,7 +10226,7 @@ simplify_stmt_using_ranges (gimple_stmt_
 	CASE_CONVERT:
 	  if (TREE_CODE (rhs1) == SSA_NAME
 	      && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
-	    return simplify_conversion_using_ranges (stmt);
+	    return simplify_conversion_using_ranges (gsi, stmt);
 	  break;
 
 	case FLOAT_EXPR:
@@ -10244,7 +10237,7 @@ simplify_stmt_using_ranges (gimple_stmt_
 
 	case MIN_EXPR:
 	case MAX_EXPR:
-	  return simplify_min_or_max_using_ranges (stmt);
+	  return simplify_min_or_max_using_ranges (gsi, stmt);
 
 	default:
 	  break;
Index: gcc/testsuite/gcc.dg/torture/pr77920.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr77920.c	(revision 0)
+++ gcc/testsuite/gcc.dg/torture/pr77920.c	(working copy)
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+
+int a, b;
+void fn1()
+{
+  int c;
+  for (; b < 0;)
+    {
+	{
+	  int d = 56, e = (b >> 3) - (d >> 3) > 0 ? (b >> 3) - (d >> 3)
+	      : -((b >> 3) - (d >> 3));
+	  c = 1 >= e;
+	}
+      if (c)
+	a = 0;
+    }
+}



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