From: Richard Kenner <kenner@gcc.gnu.org>
Date: Sun, 21 Mar 1993 01:49:22 +0000 (-0500)
Subject: (fold, case PLUS_EXPR): Don't associate apart a constant operand.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ca86a57ae73f553818ebadb894d422930648a6e1;p=gcc.git

(fold, case PLUS_EXPR): Don't associate apart a constant operand.

From-SVN: r3807
---

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index ec04f44ae65..97cb12374ce 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -3424,6 +3424,12 @@ fold (expr)
 		  if (code == PLUS_EXPR && operand_equal_p (var, arg1, 0))
 		    return convert (TREE_TYPE (t), con);
 		    
+		  /* If ARG0 is a constant, don't change things around;
+		     instead keep all the constant computations together.  */
+
+		  if (TREE_CONSTANT (arg0))
+		    return t;
+
 		  /* Otherwise return (CON +- ARG1) - VAR.  */
 		  TREE_SET_CODE (t, MINUS_EXPR);
 		  TREE_OPERAND (t, 1) = var;
@@ -3437,6 +3443,12 @@ fold (expr)
 		  if (code == MINUS_EXPR && operand_equal_p (var, arg1, 0))
 		    return convert (TREE_TYPE (t), con);
 		    
+		  /* If ARG0 is a constant, don't change things around;
+		     instead keep all the constant computations together.  */
+
+		  if (TREE_CONSTANT (arg0))
+		    return t;
+
 		  /* Otherwise return VAR +- (ARG1 +- CON).  */
 		  TREE_OPERAND (t, 1) = tem
 		    = fold (build (code, TREE_TYPE (t), arg1, con));
@@ -3464,9 +3476,6 @@ fold (expr)
 	  if (split_tree (arg1, code, &var, &con, &varsign))
 	    {
 	      /* EXPR is ARG0 +- (CON +- VAR).  */
-	      if (varsign == -1)
-		TREE_SET_CODE (t,
-			       (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
 	      if (TREE_CODE (t) == MINUS_EXPR
 		  && operand_equal_p (var, arg0, 0))
 		{
@@ -3476,6 +3485,11 @@ fold (expr)
 		  return fold (build1 (NEGATE_EXPR, TREE_TYPE (t),
 				       convert (TREE_TYPE (t), con)));
 		}
+	      if (TREE_CONSTANT (arg1))
+		return t;
+	      if (varsign == -1)
+		TREE_SET_CODE (t,
+			       (code == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR));
 	      TREE_OPERAND (t, 0)
 		= fold (build (code, TREE_TYPE (t), arg0, con));
 	      TREE_OPERAND (t, 1) = var;