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[PATCH][match-and-simplify] More ternary commutative ops, canonicalize operand order before generic_simplify


This patch (also applicable to trunk) makes us canoncialize operand
order for comparisons at the same time we canonicalize other
operand order, in particular before dispatching to generic_simplify.
It also adds operand canonicalization to ternary ops and adds
FMA_EXPR and DOT_PROD_EXPR to the list of ternary commutative ops.

Bootstrap and regtest running on match-and-simplify branch and 
x86_64-unknown-linux-gnu.

Richard.

2014-10-16  Richard Biener  <rguenther@suse.de>

	* fold-const.c (fold_comparison): Remove redundant constant
	folding and operand swapping.
	(fold_binary_loc): Do comparison operand swapping here,
	dispatch to generic_simplify after operand canonicalization.
	(fold_ternary_loc): Canonicalize operand order for
	commutative ternary operations.
	* tree.c (commutative_ternary_tree_code): Add DOT_PROD_EXPR
	and FMA_EXPR.

Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c	(revision 216262)
+++ gcc/fold-const.c	(working copy)
@@ -8726,14 +8726,6 @@ fold_comparison (location_t loc, enum tr
   STRIP_SIGN_NOPS (arg0);
   STRIP_SIGN_NOPS (arg1);
 
-  tem = fold_relational_const (code, type, arg0, arg1);
-  if (tem != NULL_TREE)
-    return tem;
-
-  /* If one arg is a real or integer constant, put it last.  */
-  if (tree_swap_operands_p (arg0, arg1, true))
-    return fold_build2_loc (loc, swap_tree_comparison (code), type, op1, op0);
-
   /* Transform comparisons of the form X +- C1 CMP C2 to X CMP C2 -+ C1.  */
   if ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
       && (equality_code || TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg0)))
@@ -9914,17 +9906,23 @@ fold_binary_loc (location_t loc,
 	}
     }
 
-  extern tree generic_simplify (enum tree_code, tree, tree, tree);
-  tem = generic_simplify (code, type, op0, op1);
-  if (tem)
-    return tem;
-
   /* If this is a commutative operation, and ARG0 is a constant, move it
      to ARG1 to reduce the number of tests below.  */
   if (commutative_tree_code (code)
       && tree_swap_operands_p (arg0, arg1, true))
     return fold_build2_loc (loc, code, type, op1, op0);
 
+  /* Likewise if this is a comparison, and ARG0 is a constant, move it
+     to ARG1 to reduce the number of tests below.  */
+  if (kind == tcc_comparison
+      && tree_swap_operands_p (arg0, arg1, true))
+    return fold_build2_loc (loc, swap_tree_comparison (code), type, op1, op0);
+
+  extern tree generic_simplify (enum tree_code, tree, tree, tree);
+  tem = generic_simplify (code, type, op0, op1);
+  if (tem)
+    return tem;
+
   /* ARG0 is the first operand of EXPR, and ARG1 is the second operand.
 
      First check for cases where an arithmetic operation is applied to a
@@ -13809,6 +13807,12 @@ fold_ternary_loc (location_t loc, enum t
   gcc_assert (IS_EXPR_CODE_CLASS (kind)
 	      && TREE_CODE_LENGTH (code) == 3);
 
+  /* If this is a commutative operation, and OP0 is a constant, move it
+     to OP1 to reduce the number of tests below.  */
+  if (commutative_ternary_tree_code (code)
+      && tree_swap_operands_p (op0, op1, true))
+    return fold_build3_loc (loc, code, type, op1, op0, op2);
+
   extern tree generic_simplify (enum tree_code, tree, tree, tree, tree);
   tem = generic_simplify (code, type, op0, op1, op2);
   if (tem)
Index: gcc/tree.c
===================================================================
--- gcc/tree.c	(revision 216244)
+++ gcc/tree.c	(working copy)
@@ -7380,6 +7380,8 @@ commutative_ternary_tree_code (enum tree
     {
     case WIDEN_MULT_PLUS_EXPR:
     case WIDEN_MULT_MINUS_EXPR:
+    case DOT_PROD_EXPR:
+    case FMA_EXPR:
       return true;
 
     default:


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