[pypy-commit] pypy default: Optimize int_xor(_, 0)

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r66250:0a2651680d0a
Date: 2013-08-20 10:31 +0200
http://bitbucket.org/pypy/pypy/changeset/0a2651680d0a/

Log:	Optimize int_xor(_, 0)

diff --git a/rpython/jit/metainterp/optimizeopt/rewrite.py b/rpython/jit/metainterp/optimizeopt/rewrite.py
--- a/rpython/jit/metainterp/optimizeopt/rewrite.py
+++ b/rpython/jit/metainterp/optimizeopt/rewrite.py
@@ -178,6 +178,17 @@
         else:
             self.emit_operation(op)
 
+    def optimize_INT_XOR(self, op):
+        v1 = self.getvalue(op.getarg(0))
+        v2 = self.getvalue(op.getarg(1))
+
+        if v1.is_constant() and v1.box.getint() == 0:
+            self.make_equal_to(op.result, v2)
+        elif v2.is_constant() and v2.box.getint() == 0:
+            self.make_equal_to(op.result, v1)
+        else:
+            self.emit_operation(op)
+
     def optimize_FLOAT_MUL(self, op):
         arg1 = op.getarg(0)
         arg2 = op.getarg(1)
diff --git a/rpython/jit/metainterp/optimizeopt/test/test_optimizeopt.py b/rpython/jit/metainterp/optimizeopt/test/test_optimizeopt.py
--- a/rpython/jit/metainterp/optimizeopt/test/test_optimizeopt.py
+++ b/rpython/jit/metainterp/optimizeopt/test/test_optimizeopt.py
@@ -3263,6 +3263,20 @@
         """
         self.optimize_loop(ops, expected)
 
+    def test_fold_partially_constant_xor(self):
+        ops = """
+        [i0, i1]
+        i2 = int_xor(i0, 23)
+        i3 = int_xor(i1, 0)
+        jump(i2, i3)
+        """
+        expected = """
+        [i0, i1]
+        i2 = int_xor(i0, 23)
+        jump(i2, i1)
+        """
+        self.optimize_loop(ops, expected)
+
     # ----------
 
     def test_residual_call_does_not_invalidate_caches(self):