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* [PATCH] Move A - (A & B) -> ~B & A
@ 2015-07-17 11:05 Marek Polacek
  2015-07-17 12:57 ` Richard Biener
  0 siblings, 1 reply; 5+ messages in thread
From: Marek Polacek @ 2015-07-17 11:05 UTC (permalink / raw)
  To: GCC Patches, Richard Biener

This moves one pattern from fold-const.c into match.pd.
Since no test was testing that pattern, I added a new test.
As a follow up I'll move the "(A & ~B) - (A & B) into (A ^ B) - B"
pattern.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2015-07-17  Marek Polacek  <polacek@redhat.com>

	* fold-const.c (fold_binary_loc): Move A - (A & B) into ~B & A ...
	* match.pd: ... here.

	* gcc.dg/fold-minus-7.c: New test.

diff --git gcc/fold-const.c gcc/fold-const.c
index 93dd29d..fa321f4 100644
--- gcc/fold-const.c
+++ gcc/fold-const.c
@@ -9777,30 +9777,6 @@ fold_binary_loc (location_t loc,
 
       if (! FLOAT_TYPE_P (type))
 	{
-	  /* Fold A - (A & B) into ~B & A.  */
-	  if (!TREE_SIDE_EFFECTS (arg0)
-	      && TREE_CODE (arg1) == BIT_AND_EXPR)
-	    {
-	      if (operand_equal_p (arg0, TREE_OPERAND (arg1, 1), 0))
-		{
-		  tree arg10 = fold_convert_loc (loc, type,
-						 TREE_OPERAND (arg1, 0));
-		  return fold_build2_loc (loc, BIT_AND_EXPR, type,
-				      fold_build1_loc (loc, BIT_NOT_EXPR,
-						   type, arg10),
-				      fold_convert_loc (loc, type, arg0));
-		}
-	      if (operand_equal_p (arg0, TREE_OPERAND (arg1, 0), 0))
-		{
-		  tree arg11 = fold_convert_loc (loc,
-						 type, TREE_OPERAND (arg1, 1));
-		  return fold_build2_loc (loc, BIT_AND_EXPR, type,
-				      fold_build1_loc (loc, BIT_NOT_EXPR,
-						   type, arg11),
-				      fold_convert_loc (loc, type, arg0));
-		}
-	    }
-
 	  /* Fold (A & ~B) - (A & B) into (A ^ B) - B, where B is
 	     any power of 2 minus 1.  */
 	  if (TREE_CODE (arg0) == BIT_AND_EXPR
diff --git gcc/match.pd gcc/match.pd
index c335ada..066d5de 100644
--- gcc/match.pd
+++ gcc/match.pd
@@ -662,6 +662,10 @@ along with GCC; see the file COPYING3.  If not see
  (bit_ior:c (bit_and:cs @0 (bit_not @2)) (bit_and:cs @1 @2))
  (bit_xor (bit_and (bit_xor @0 @1) @2) @0))
 
+/* Fold A - (A & B) into ~B & A.  */
+(simplify
+ (minus (convert? @0) (convert? (bit_and:c @0 @1)))
+ (convert (bit_and (bit_not @1) @0)))
 
 /* Associate (p +p off1) +p off2 as (p +p (off1 + off2)).  */
 (simplify
diff --git gcc/testsuite/gcc.dg/fold-minus-7.c gcc/testsuite/gcc.dg/fold-minus-7.c
index e69de29..7a49faa 100644
--- gcc/testsuite/gcc.dg/fold-minus-7.c
+++ gcc/testsuite/gcc.dg/fold-minus-7.c
@@ -0,0 +1,36 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-cddce1" } */
+
+int
+f1 (int a, int b)
+{
+  int tem = a & b;
+  return a - tem;
+}
+
+int
+f2 (int a, int b)
+{
+  int tem = b & a;
+  return a - tem;
+}
+
+int
+f3 (unsigned int a, int b)
+{
+  return a - (a & b);
+}
+
+int
+f4 (int a, unsigned int b)
+{
+  return a - (a & b);
+}
+
+int
+f5 (int a, int b)
+{
+  return a - (unsigned) (b & a);
+}
+
+/* { dg-final { scan-tree-dump-not " - " "cddce1" } } */

	Marek

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2015-08-13 21:08 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-07-17 11:05 [PATCH] Move A - (A & B) -> ~B & A Marek Polacek
2015-07-17 12:57 ` Richard Biener
2015-07-17 15:43   ` Marek Polacek
2015-07-17 16:01     ` Richard Biener
2015-08-13 21:26     ` Marc Glisse

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