[pypy-commit] pypy default: int_floordiv(i0, 1) is always equal to i0.

[alex_gaynor]

Author: Alex Gaynor <alex.gaynor at gmail.com>
Branch: 
Changeset: r44598:3380961ff42e
Date: 2011-05-30 11:30 -0700
http://bitbucket.org/pypy/pypy/changeset/3380961ff42e/

Log:	int_floordiv(i0, 1) is always equal to i0.

diff --git a/pypy/jit/metainterp/optimizeopt/rewrite.py b/pypy/jit/metainterp/optimizeopt/rewrite.py
--- a/pypy/jit/metainterp/optimizeopt/rewrite.py
+++ b/pypy/jit/metainterp/optimizeopt/rewrite.py
@@ -432,6 +432,9 @@
         v1 = self.getvalue(op.getarg(0))
         v2 = self.getvalue(op.getarg(1))
 
+        if v2.is_constant() and v2.box.getint() == 1:
+            self.make_equal_to(op.result, v1)
+            return
         if v1.intbound.known_ge(IntBound(0, 0)) and v2.is_constant():
             val = v2.box.getint()
             if val & (val - 1) == 0 and val > 0: # val == 2**shift
diff --git a/pypy/jit/metainterp/test/test_optimizeopt.py b/pypy/jit/metainterp/test/test_optimizeopt.py
--- a/pypy/jit/metainterp/test/test_optimizeopt.py
+++ b/pypy/jit/metainterp/test/test_optimizeopt.py
@@ -3899,7 +3899,7 @@
         jump(i4, i10)
         """
         self.optimize_loop(ops, expected)
-        
+
     def test_add_sub_ovf(self):
         ops = """
         [i1]
@@ -3939,7 +3939,7 @@
         [i0, i1]
         escape(i1)
         i2 = int_add_ovf(i0, 1)
-        guard_no_overflow() []        
+        guard_no_overflow() []
         jump(i2, i0)
         """
         self.optimize_loop(ops, expected)
@@ -4420,7 +4420,6 @@
         i8 = int_floordiv(4, i2)
         i9 = int_rshift(i1, 2)
         i10 = int_floordiv(i1, 0)
-        i11 = int_rshift(i1, 0)
         i12 = int_floordiv(i2, 2)
         i13 = int_floordiv(i2, 3)
         i14 = int_floordiv(i2, 4)
@@ -4497,6 +4496,18 @@
         """
         self.optimize_loop(ops, expected)
 
+    def test_int_div_1(self):
+        ops = """
+        [i0]
+        i1 = int_floordiv(i0, 1)
+        jump(i1)
+        """
+        expected = """
+        [i0]
+        jump(i0)
+        """
+        self.optimize_loop(ops, expected)
+
     def test_subsub_ovf(self):
         ops = """
         [i0]