[pypy-commit] pypy default: Make the optimizer recognize the effect that int_is_true(); guard_true() has on the bounds. Specifically this removes an op + a guard in the case of something like `if x and x[0] == "f"` where x is a string at app level.

[alex_gaynor]

Author: Alex Gaynor <alex.gay...@gmail.com>
Branch: 
Changeset: r45149:440bff536936
Date: 2011-06-27 14:03 -0700
http://bitbucket.org/pypy/pypy/changeset/440bff536936/

Log:    Make the optimizer recognize the effect that int_is_true();
        guard_true() has on the bounds. Specifically this removes an op + a
        guard in the case of something like `if x and x[0] == "f"` where x
        is a string at app level.

diff --git a/pypy/jit/metainterp/optimizeopt/intbounds.py 
b/pypy/jit/metainterp/optimizeopt/intbounds.py
--- a/pypy/jit/metainterp/optimizeopt/intbounds.py
+++ b/pypy/jit/metainterp/optimizeopt/intbounds.py
@@ -1,7 +1,7 @@
 from pypy.jit.metainterp.optimizeopt.optimizer import Optimization, CONST_1, 
CONST_0
 from pypy.jit.metainterp.optimizeopt.util import _findall
-from pypy.jit.metainterp.optimizeopt.intutils import IntBound, IntUnbounded, \
-    IntLowerBound, IntUpperBound
+from pypy.jit.metainterp.optimizeopt.intutils import (IntBound, IntUnbounded,
+    IntLowerBound, IntUpperBound)
 from pypy.jit.metainterp.history import Const, ConstInt
 from pypy.jit.metainterp.resoperation import rop, ResOperation
 
@@ -373,6 +373,15 @@
                 if v2.intbound.intersect(v1.intbound):
                     self.propagate_bounds_backward(op.getarg(1))
 
+    def propagate_bounds_INT_IS_TRUE(self, op):
+        r = self.getvalue(op.result)
+        if r.is_constant():
+            if r.box.same_constant(CONST_1):
+                v1 = self.getvalue(op.getarg(0))
+                if v1.intbound.known_ge(IntBound(0, 0)):
+                    v1.intbound.make_gt(IntBound(0, 0))
+                    self.propagate_bounds_backward(op.getarg(0))
+
     def propagate_bounds_INT_ADD(self, op):
         v1 = self.getvalue(op.getarg(0))
         v2 = self.getvalue(op.getarg(1))
@@ -418,5 +427,6 @@
     propagate_bounds_INT_SUB_OVF  = propagate_bounds_INT_SUB
     propagate_bounds_INT_MUL_OVF  = propagate_bounds_INT_MUL
 
+
 optimize_ops = _findall(OptIntBounds, 'optimize_')
 propagate_bounds_ops = _findall(OptIntBounds, 'propagate_bounds_')
diff --git a/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py 
b/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py
--- a/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py
+++ b/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py
@@ -4497,6 +4497,25 @@
         """
         self.optimize_loop(ops, expected)
 
+    def test_int_is_true_bounds(self):
+        ops = """
+        [p0]
+        i0 = strlen(p0)
+        i1 = int_is_true(i0)
+        guard_true(i1) []
+        i2 = int_ge(0, i0)
+        guard_false(i2) []
+        jump(p0)
+        """
+        expected = """
+        [p0]
+        i0 = strlen(p0)
+        i1 = int_is_true(i0)
+        guard_true(i1) []
+        jump(p0)
+        """
+        self.optimize_loop(ops, expected)
+
 
 class TestLLtype(BaseTestOptimizeBasic, LLtypeMixin):
     pass
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