match: Add support for `a ^ CST` to bitwise_inverted_equal_p [PR115224]

While looking into something else, I noticed that `a ^ CST` needed to be
special casing to bitwise_inverted_equal_p as it would simplify to `a ^ ~CST`
for the bitwise not.

Bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR tree-optimization/115224

gcc/ChangeLog:

	* generic-match-head.cc (bitwise_inverted_equal_p): Add `a ^ CST`
	case.
	* gimple-match-head.cc (gimple_bit_xor_cst): New declaration.
	(gimple_bitwise_inverted_equal_p): Add `a ^ CST` case.
	* match.pd (bit_xor_cst): New match.
	(maybe_bit_not): Add bit_xor_cst case.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/bitops-8.c: New test.

Signed-off-by: Andrew Pinski <quic_apinski@quicinc.com>

4 files changed, 42 insertions, 0 deletions

diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc
index 55ba369..641d8e9 100644
--- a/gcc/generic-match-head.cc
+++ b/gcc/generic-match-head.cc
@@ -158,6 +158,16 @@ bitwise_inverted_equal_p (tree expr1, tree expr2, bool &wascmp)
   if (TREE_CODE (expr2) == BIT_NOT_EXPR
       && bitwise_equal_p (expr1, TREE_OPERAND (expr2, 0)))
     return true;
+
+  /* `X ^ CST` and `X ^ ~CST` match for ~. */
+  if (TREE_CODE (expr1) == BIT_XOR_EXPR && TREE_CODE (expr2) == BIT_XOR_EXPR
+      && bitwise_equal_p (TREE_OPERAND (expr1, 0), TREE_OPERAND (expr2, 0)))
+    {
+      tree cst1 = uniform_integer_cst_p (TREE_OPERAND (expr1, 1));
+      tree cst2 = uniform_integer_cst_p (TREE_OPERAND (expr2, 1));
+      if (cst1 && cst2 && wi::to_wide (cst1) == ~wi::to_wide (cst2))
+	return true;
+    }
   if (COMPARISON_CLASS_P (expr1)
       && COMPARISON_CLASS_P (expr2))
     {
diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc
index 6220725..e26fa08 100644
--- a/gcc/gimple-match-head.cc
+++ b/gcc/gimple-match-head.cc
@@ -283,6 +283,7 @@ gimple_bitwise_equal_p (tree expr1, tree expr2, tree (*valueize) (tree))
 
 bool gimple_bit_not_with_nop (tree, tree *, tree (*) (tree));
 bool gimple_maybe_cmp (tree, tree *, tree (*) (tree));
+bool gimple_bit_xor_cst (tree, tree *, tree (*) (tree));
 
 /* Helper function for bitwise_inverted_equal_p macro.  */
 
@@ -301,6 +302,18 @@ gimple_bitwise_inverted_equal_p (tree expr1, tree expr2, bool &wascmp, tree (*va
   if (operand_equal_p (expr1, expr2, 0))
     return false;
 
+  tree xor1[2];
+  tree xor2[2];
+  /* `X ^ CST` and `X ^ ~CST` match for ~. */
+  if (gimple_bit_xor_cst (expr1, xor1, valueize)
+      && gimple_bit_xor_cst (expr2, xor2, valueize))
+    {
+      if (operand_equal_p (xor1[0], xor2[0], 0)
+	  && (wi::to_wide (uniform_integer_cst_p (xor1[1]))
+	      == ~wi::to_wide (uniform_integer_cst_p (xor2[1]))))
+	return true;
+    }
+
   tree other;
   /* Try if EXPR1 was defined as ~EXPR2. */
   if (gimple_bit_not_with_nop (expr1, &other, valueize))
diff --git a/gcc/match.pd b/gcc/match.pd
index 090ad4e..480e36b 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -174,6 +174,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 (match (bit_not_with_nop @0)
  (convert (bit_not @0))
  (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))))
+(match (bit_xor_cst @0 @1)
+ (bit_xor @0 uniform_integer_cst_p@1))
 (for cmp (tcc_comparison)
  (match (maybe_cmp @0)
   (cmp@0 @1 @2))
@@ -195,6 +197,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (INTEGER_CST@0))
 (match (maybe_bit_not @0)
  (maybe_cmp@0 @1))
+(match (maybe_bit_not @0)
+ (bit_xor_cst@0 @1 @2))
 
 /* Transform likes of (char) ABS_EXPR <(int) x> into (char) ABSU_EXPR <x>
    ABSU_EXPR returns unsigned absolute value of the operand and the operand
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c b/gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c
new file mode 100644
index 0000000..40f756e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-8.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
+/* PR tree-optimization/115224 */
+
+int f1(int a, int b)
+{
+        a = a ^ 1;
+        int c = ~a;
+        return c | (a ^ b);
+        // ~((a ^ 1) & b) or (a ^ -2) | ~b
+}
+/* { dg-final { scan-tree-dump-times   "bit_xor_expr, "  1  "optimized" } } */
+/* { dg-final { scan-tree-dump-times   "bit_ior_expr, "  1  "optimized" } } */
+/* { dg-final { scan-tree-dump-times   "bit_not_expr, "  1  "optimized" } } */
+