Move X==15-X to match.pd

2017-05-18  Marc Glisse  <marc.glisse@inria.fr>

	* fold-const.c (fold_binary_loc): Move transformation...
	* match.pd (C - X CMP X): ... here.

From-SVN: r248193

gcc/ChangeLog

+2017-05-18  Marc Glisse  <marc.glisse@inria.fr>
+
+	* fold-const.c (fold_binary_loc): Move transformation...
+	* match.pd (C - X CMP X): ... here.
+
 2017-05-18  Sheldon Lobo  <sheldon.lobo@oracle.com>
 
 	* config/sparc/sparc.c (sparc_option_override): Set function

gcc/fold-const.c

@@ -10532,30 +10532,6 @@ fold_binary_loc (location_t loc,
 					TREE_OPERAND (arg1, 0), arg0);
 	}
 
-      /* Transform comparisons of the form C - X CMP X if C % 2 == 1.  */
-      if (TREE_CODE (arg0) == MINUS_EXPR
-	  && TREE_CODE (TREE_OPERAND (arg0, 0)) == INTEGER_CST
-	  && operand_equal_p (tree_strip_nop_conversions (TREE_OPERAND (arg0,
-									1)),
-			      arg1, 0)
-	  && wi::extract_uhwi (TREE_OPERAND (arg0, 0), 0, 1) == 1)
-	return omit_two_operands_loc (loc, type,
-				      code == NE_EXPR
-				      ? boolean_true_node : boolean_false_node,
-				      TREE_OPERAND (arg0, 1), arg1);
-
-      /* Transform comparisons of the form X CMP C - X if C % 2 == 1.  */
-      if (TREE_CODE (arg1) == MINUS_EXPR
-	  && TREE_CODE (TREE_OPERAND (arg1, 0)) == INTEGER_CST
-	  && operand_equal_p (tree_strip_nop_conversions (TREE_OPERAND (arg1,
-									1)),
-			      arg0, 0)
-	  && wi::extract_uhwi (TREE_OPERAND (arg1, 0), 0, 1) == 1)
-	return omit_two_operands_loc (loc, type,
-				      code == NE_EXPR
-				      ? boolean_true_node : boolean_false_node,
-				      TREE_OPERAND (arg1, 1), arg0);
-
       /* If this is an EQ or NE comparison with zero and ARG0 is
 	 (1 << foo) & bar, convert it to (bar >> foo) & 1.  Both require
 	 two operations, but the latter can be done in one less insn

gcc/match.pd

@@ -1090,6 +1090,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	   || TYPE_OVERFLOW_WRAPS (TREE_TYPE (@0))))
    (op @1 @0))))
 
+/* X == C - X can never be true if C is odd.  */
+(for cmp (eq ne)
+ (simplify
+  (cmp:c (convert? @0) (convert1? (minus INTEGER_CST@1 (convert2? @0))))
+  (if (TREE_INT_CST_LOW (@1) & 1)
+   { constant_boolean_node (cmp == NE_EXPR, type); })))
+
 /* ((X inner_op C0) outer_op C1)
    With X being a tree where value_range has reasoned certain bits to always be
    zero throughout its computed value range,