fold-const.c (fold_cond_expr_with_comparison): Move simplification for A cmp C1 ? A : C2 to below, also simplify remaining code.

	* fold-const.c (fold_cond_expr_with_comparison): Move simplification
	for A cmp C1 ? A : C2 to below, also simplify remaining code.
	* match.pd: Move and extend simplification from above to here:
	(cond (cmp (convert1? x) c1) (convert2? x) c2) -> (minmax (x c)).
	* tree-if-conv.c (ifcvt_follow_ssa_use_edges): New func.
	(predicate_scalar_phi): Call fold_stmt using the new valueize func.

	gcc/testsuite
	* gcc.dg/fold-cond_expr-1.c: New test.
	* gcc.dg/fold-condcmpconv-1.c: New test.
	* gcc.dg/fold-condcmpconv-2.c: New test.

From-SVN: r242750

1 files changed, 9 insertions, 86 deletions

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index a0055c4..cbfbc24 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -5210,95 +5210,18 @@ fold_cond_expr_with_comparison (location_t loc, tree type,
 	}
     }
 
-  /* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
-     we might still be able to simplify this.  For example,
-     if C1 is one less or one more than C2, this might have started
-     out as a MIN or MAX and been transformed by this function.
-     Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE.  */
+  /* If this is A == C1 ? A : C2 with C1 and C2 constant integers,
+     we simplify it into A == C1 ? C1 : C2.  */
 
-  if (INTEGRAL_TYPE_P (type)
+  if (comp_code == EQ_EXPR
+      && INTEGRAL_TYPE_P (type)
       && TREE_CODE (arg01) == INTEGER_CST
+      && TREE_CODE (arg1) != INTEGER_CST
       && TREE_CODE (arg2) == INTEGER_CST)
-    switch (comp_code)
-      {
-      case EQ_EXPR:
-	if (TREE_CODE (arg1) == INTEGER_CST)
-	  break;
-	/* We can replace A with C1 in this case.  */
-	arg1 = fold_convert_loc (loc, type, arg01);
-	return fold_build3_loc (loc, COND_EXPR, type, arg0, arg1, arg2);
-
-      case LT_EXPR:
-	/* If C1 is C2 + 1, this is min(A, C2), but use ARG00's type for
-	   MIN_EXPR, to preserve the signedness of the comparison.  */
-	if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type),
-			       OEP_ONLY_CONST)
-	    && operand_equal_p (arg01,
-				const_binop (PLUS_EXPR, arg2,
-					     build_int_cst (type, 1)),
-				OEP_ONLY_CONST))
-	  {
-	    tem = fold_build2_loc (loc, MIN_EXPR, TREE_TYPE (arg00), arg00,
-				   fold_convert_loc (loc, TREE_TYPE (arg00),
-						     arg2));
-	    return fold_convert_loc (loc, type, tem);
-	  }
-	break;
-
-      case LE_EXPR:
-	/* If C1 is C2 - 1, this is min(A, C2), with the same care
-	   as above.  */
-	if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type),
-			       OEP_ONLY_CONST)
-	    && operand_equal_p (arg01,
-				const_binop (MINUS_EXPR, arg2,
-					     build_int_cst (type, 1)),
-				OEP_ONLY_CONST))
-	  {
-	    tem = fold_build2_loc (loc, MIN_EXPR, TREE_TYPE (arg00), arg00,
-				   fold_convert_loc (loc, TREE_TYPE (arg00),
-						     arg2));
-	    return fold_convert_loc (loc, type, tem);
-	  }
-	break;
-
-      case GT_EXPR:
-	/* If C1 is C2 - 1, this is max(A, C2), but use ARG00's type for
-	   MAX_EXPR, to preserve the signedness of the comparison.  */
-	if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type),
-			       OEP_ONLY_CONST)
-	    && operand_equal_p (arg01,
-				const_binop (MINUS_EXPR, arg2,
-					     build_int_cst (type, 1)),
-				OEP_ONLY_CONST))
-	  {
-	    tem = fold_build2_loc (loc, MAX_EXPR, TREE_TYPE (arg00), arg00,
-				   fold_convert_loc (loc, TREE_TYPE (arg00),
-						     arg2));
-	    return fold_convert_loc (loc, type, tem);
-	  }
-	break;
-
-      case GE_EXPR:
-	/* If C1 is C2 + 1, this is max(A, C2), with the same care as above.  */
-	if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type),
-			       OEP_ONLY_CONST)
-	    && operand_equal_p (arg01,
-				const_binop (PLUS_EXPR, arg2,
-					     build_int_cst (type, 1)),
-				OEP_ONLY_CONST))
-	  {
-	    tem = fold_build2_loc (loc, MAX_EXPR, TREE_TYPE (arg00), arg00,
-				   fold_convert_loc (loc, TREE_TYPE (arg00),
-						     arg2));
-	    return fold_convert_loc (loc, type, tem);
-	  }
-	break;
-      case NE_EXPR:
-	break;
-      default:
-	gcc_unreachable ();
-      }
+    {
+      arg1 = fold_convert_loc (loc, type, arg01);
+      return fold_build3_loc (loc, COND_EXPR, type, arg0, arg1, arg2);
+    }
 
   return NULL_TREE;
 }