[pypy-commit] pypy default: the optimization does not actually work for -maxint-1

[cfbolz]

Author: Carl Friedrich Bolz <cfbolz at gmx.de>
Branch: 
Changeset: r76249:58bec7621db5
Date: 2015-03-05 15:17 +0100
http://bitbucket.org/pypy/pypy/changeset/58bec7621db5/

Log:	the optimization does not actually work for -maxint-1

diff --git a/rpython/jit/metainterp/optimizeopt/optimizer.py b/rpython/jit/metainterp/optimizeopt/optimizer.py
--- a/rpython/jit/metainterp/optimizeopt/optimizer.py
+++ b/rpython/jit/metainterp/optimizeopt/optimizer.py
@@ -862,6 +862,7 @@
         return resbox.constbox()
 
     def pure_reverse(self, op):
+        import sys
         if self.optpure is None:
             return
         optpure = self.optpure
@@ -875,10 +876,14 @@
             if isinstance(arg0, ConstInt):
                 # invert the constant
                 i0 = arg0.getint()
+                if i0 == -sys.maxint - 1:
+                    return
                 inv_arg0 = ConstInt(-i0)
             elif isinstance(arg1, ConstInt):
                 # commutative
                 i0 = arg1.getint()
+                if i0 == -sys.maxint - 1:
+                    return
                 inv_arg0 = ConstInt(-i0)
                 arg1 = arg0
             else:
@@ -896,6 +901,8 @@
             if isinstance(arg1, ConstInt):
                 # invert the constant
                 i1 = arg1.getint()
+                if i1 == -sys.maxint - 1:
+                    return
                 inv_arg1 = ConstInt(-i1)
                 optpure.pure(rop.INT_ADD, [arg0, inv_arg1], op.result)
                 optpure.pure(rop.INT_ADD, [inv_arg1, arg0], op.result)
diff --git a/rpython/jit/metainterp/optimizeopt/test/test_optimizebasic.py b/rpython/jit/metainterp/optimizeopt/test/test_optimizebasic.py
--- a/rpython/jit/metainterp/optimizeopt/test/test_optimizebasic.py
+++ b/rpython/jit/metainterp/optimizeopt/test/test_optimizebasic.py
@@ -3704,6 +3704,7 @@
         self.optimize_loop(ops, expected)
 
     def test_int_add_sub_constants_inverse(self):
+        import sys
         ops = """
         [i0, i10, i11, i12, i13]
         i2 = int_add(1, i0)
@@ -3748,6 +3749,14 @@
         jump(i0, i2, i2, i2, i0, -1)
         """
         self.optimize_loop(ops, expected)
+        ops = """
+        [i0, i10, i11, i12]
+        i2 = int_add(%s, i0)
+        i3 = int_add(i2, %s)
+        i4 = int_sub(i0, %s)
+        jump(i0, i2, i3, i4)
+        """ % ((-sys.maxint - 1, ) * 3)
+        self.optimize_loop(ops, ops) # does not crash
 
     def test_framestackdepth_overhead(self):
         ops = """