MATCH: [PR110937/PR100798] (a ? ~b : b) should be optimized to b ^ -(a)

This adds a simple match pattern for this case.
I noticed it a couple of different places.
One while I was looking at code generation of a parser and
also while I was looking at locations where bitwise_inverted_equal_p
should be used more.

Committed as approved after bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR tree-optimization/110937
	PR tree-optimization/100798

gcc/ChangeLog:

	* match.pd (`a ? ~b : b`): Handle this
	case.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/bool-14.c: New test.
	* gcc.dg/tree-ssa/bool-15.c: New test.
	* gcc.dg/tree-ssa/phi-opt-33.c: New test.
	* gcc.dg/tree-ssa/20030709-2.c: Update testcase
	so `a ? -1 : 0` is not used to hit the match
	pattern.

diff --git a/gcc/match.pd b/gcc/match.pd
index 9b4819e5be7a78854f632171e4e05936011fff02..fc630b63563fd352d5d60a2774210afd785be48a 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6460,6 +6460,20 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
       (if (cmp == NE_EXPR)
        { constant_boolean_node (true, type); })))))))
 
+#if GIMPLE
+/* a?~t:t -> (-(a))^t */
+(simplify
+ (cond @0 @1 @2)
+ (if (INTEGRAL_TYPE_P (type)
+      && bitwise_inverted_equal_p (@1, @2))
+  (with {
+    auto prec = TYPE_PRECISION (type);
+    auto unsign = TYPE_UNSIGNED (type);
+    tree inttype = build_nonstandard_integer_type (prec, unsign);
+   }
+   (convert (bit_xor (negate (convert:inttype @0)) (convert:inttype @2))))))
+#endif
+
 /* Simplify pointer equality compares using PTA.  */
 (for neeq (ne eq)
  (simplify

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c b/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
index 5009cd69cfe81fa41d56e14a74ee05bac9e90ff3..78938f919d46c6551f5dc1a4d771f75d59ab56ca 100644 (file)
--- a/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
@@ -29,15 +29,16 @@ union tree_node
 };
 int make_decl_rtl (tree, int);
 void *
-get_alias_set (t)
+get_alias_set (t, t1)
      tree t;
+     void *t1;
 {
   long set;
   if (t->decl.rtl)
     return (t->decl.rtl->fld[1].rtmem 
            ? 0
            : (((t->decl.rtl ? t->decl.rtl: (make_decl_rtl (t, 0), t->decl.rtl)))->fld[1]).rtmem);
-  return (void*)-1;
+  return t1;
 }
 
 /* There should be precisely one load of ->decl.rtl.  If there is

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-14.c b/gcc/testsuite/gcc.dg/tree-ssa/bool-14.c
new file mode 100644 (file)
index 0000000..0149380
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-14.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+/* PR tree-optimization/110937 */
+
+_Bool f2(_Bool a, _Bool b)
+{
+        if (a)
+          return !b;
+        return b;
+}
+
+/* We should be able to remove the conditional and convert it to an xor. */
+/* { dg-final { scan-tree-dump-not "gimple_cond " "optimized" } } */
+/* { dg-final { scan-tree-dump-not "gimple_phi " "optimized" } } */
+/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-15.c b/gcc/testsuite/gcc.dg/tree-ssa/bool-15.c
new file mode 100644 (file)
index 0000000..1f49666
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-15.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+/* PR tree-optimization/110937 */
+
+_Bool f2(int x, int y, int w, int z)
+{
+  _Bool a = x == y;
+  _Bool b = w == z;
+  if (a)
+    return !b;
+  return b;
+}
+
+/* We should be able to remove the conditional and convert it to an xor. */
+/* { dg-final { scan-tree-dump-not "gimple_cond " "optimized" } } */
+/* { dg-final { scan-tree-dump-not "gimple_phi " "optimized" } } */
+/* { dg-final { scan-tree-dump-not "ne_expr, " "optimized" } } */
+/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } } */

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c
new file mode 100644 (file)
index 0000000..b79fe44
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+/* PR tree-optimization/100798 */
+
+int f(int a, int t)
+{
+  return (a=='s' ? ~t : t);
+}
+
+/* This should be convert into t^-(a=='s').  */
+/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "negate_expr, " 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-not "bit_not_expr, " "optimized" } } */