re PR sanitizer/85213 (-fsanitize=undefined internal compiler error: in fold_convert_loc, at fold-const.c:2402)

	PR sanitizer/85213
	* fold-const.c (twoval_comparison_p): Remove SAVE_P argument and don't
	look through SAVE_EXPRs with non-side-effects argument.  Adjust
	recursive calls.
	(fold_comparison): Adjust twoval_comparison_p caller, don't handle
	save_p here.

	* c-c++-common/ubsan/pr85213.c: New test.

From-SVN: r259167

1 files changed, 10 insertions, 34 deletions

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 014c7d4..3134f8e 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -115,7 +115,7 @@ static tree negate_expr (tree);
 static tree associate_trees (location_t, tree, tree, enum tree_code, tree);
 static enum comparison_code comparison_to_compcode (enum tree_code);
 static enum tree_code compcode_to_comparison (enum comparison_code);
-static int twoval_comparison_p (tree, tree *, tree *, int *);
+static int twoval_comparison_p (tree, tree *, tree *);
 static tree eval_subst (location_t, tree, tree, tree, tree, tree);
 static tree optimize_bit_field_compare (location_t, enum tree_code,
 					tree, tree, tree);
@@ -3549,13 +3549,12 @@ operand_equal_for_comparison_p (tree arg0, tree arg1)
    two different values, which will be stored in *CVAL1 and *CVAL2; if
    they are nonzero it means that some operands have already been found.
    No variables may be used anywhere else in the expression except in the
-   comparisons.  If SAVE_P is true it means we removed a SAVE_EXPR around
-   the expression and save_expr needs to be called with CVAL1 and CVAL2.
+   comparisons.  
 
    If this is true, return 1.  Otherwise, return zero.  */
 
 static int
-twoval_comparison_p (tree arg, tree *cval1, tree *cval2, int *save_p)
+twoval_comparison_p (tree arg, tree *cval1, tree *cval2)
 {
   enum tree_code code = TREE_CODE (arg);
   enum tree_code_class tclass = TREE_CODE_CLASS (code);
@@ -3568,39 +3567,23 @@ twoval_comparison_p (tree arg, tree *cval1, tree *cval2, int *save_p)
 	       || code == COMPOUND_EXPR))
     tclass = tcc_binary;
 
-  else if (tclass == tcc_expression && code == SAVE_EXPR
-	   && ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0)))
-    {
-      /* If we've already found a CVAL1 or CVAL2, this expression is
-	 two complex to handle.  */
-      if (*cval1 || *cval2)
-	return 0;
-
-      tclass = tcc_unary;
-      *save_p = 1;
-    }
-
   switch (tclass)
     {
     case tcc_unary:
-      return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
+      return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2);
 
     case tcc_binary:
-      return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
-	      && twoval_comparison_p (TREE_OPERAND (arg, 1),
-				      cval1, cval2, save_p));
+      return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2)
+	      && twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2));
 
     case tcc_constant:
       return 1;
 
     case tcc_expression:
       if (code == COND_EXPR)
-	return (twoval_comparison_p (TREE_OPERAND (arg, 0),
-				     cval1, cval2, save_p)
-		&& twoval_comparison_p (TREE_OPERAND (arg, 1),
-					cval1, cval2, save_p)
-		&& twoval_comparison_p (TREE_OPERAND (arg, 2),
-					cval1, cval2, save_p));
+	return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2)
+		&& twoval_comparison_p (TREE_OPERAND (arg, 1), cval1, cval2)
+		&& twoval_comparison_p (TREE_OPERAND (arg, 2), cval1, cval2));
       return 0;
 
     case tcc_comparison:
@@ -8781,9 +8764,8 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
   if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
     {
       tree cval1 = 0, cval2 = 0;
-      int save_p = 0;
 
-      if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
+      if (twoval_comparison_p (arg0, &cval1, &cval2)
 	  /* Don't handle degenerate cases here; they should already
 	     have been handled anyway.  */
 	  && cval1 != 0 && cval2 != 0
@@ -8856,12 +8838,6 @@ fold_comparison (location_t loc, enum tree_code code, tree type,
 		  return omit_one_operand_loc (loc, type, integer_one_node, arg0);
 		}
 
-	      if (save_p)
-		{
-		  tem = save_expr (build2 (code, type, cval1, cval2));
-		  protected_set_expr_location (tem, loc);
-		  return tem;
-		}
 	      return fold_build2_loc (loc, code, type, cval1, cval2);
 	    }
 	}