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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a9978bca01643c21252cd5f6e6397ba70af12768..ee04a8606804356d4f80413fb1b051d5c454d23f 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+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

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index f6d5af43b33a8141fbb93bcae537eebed6959a6c..19aa72258497b710385ce9c456614e97b4a481a8 100644 (file)
--- a/gcc/fold-const.c
+++ b/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

diff --git a/gcc/match.pd b/gcc/match.pd
index 80a17ba3d23ac9c4a679085640a52b287e6f1a3a..ba501498cdd7724621455b7cb4f1d4996020e2ae 100644 (file)
--- a/gcc/match.pd
+++ b/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,