[pypy-svn] pypy default: Remove the calls to libc's isinf again, reimplement it ourselves so the JIT can inline it nicely. Algorithm taken fromboost.

[alex_gaynor]

Author: Alex Gaynor <alex.gaynor at gmail.com>
Branch: 
Changeset: r43360:d8ea37b2a1ff
Date: 2011-04-14 18:44 +0000
http://bitbucket.org/pypy/pypy/changeset/d8ea37b2a1ff/

Log:	Remove the calls to libc's isinf again, reimplement it ourselves so
	the JIT can inline it nicely. Algorithm taken fromboost.

diff --git a/pypy/translator/c/src/ll_math.h b/pypy/translator/c/src/ll_math.h
--- a/pypy/translator/c/src/ll_math.h
+++ b/pypy/translator/c/src/ll_math.h
@@ -1,8 +1,6 @@
 /* Definitions of some C99 math library functions, for those platforms
    that don't implement these functions already. */
 
-int _pypy_math_isinf(double x);
-
 double _pypy_math_acosh(double x);
 double _pypy_math_asinh(double x);
 double _pypy_math_atanh(double x);

diff --git a/pypy/rpython/lltypesystem/module/test/test_ll_math.py b/pypy/rpython/lltypesystem/module/test/test_ll_math.py
--- a/pypy/rpython/lltypesystem/module/test/test_ll_math.py
+++ b/pypy/rpython/lltypesystem/module/test/test_ll_math.py
@@ -3,6 +3,7 @@
 
 from pypy.rpython.lltypesystem.module import ll_math
 from pypy.module.math.test.test_direct import MathTests, get_tester
+from pypy.translator.c.test.test_genc import compile
 
 
 class TestMath(MathTests):
@@ -21,6 +22,13 @@
         assert ll_math.ll_math_isnan(nan)
         assert not ll_math.ll_math_isnan(inf)
 
+    def test_compiled_isinf(self):
+        def f(x):
+            return ll_math.ll_math_isinf(1. / x)
+        f = compile(f, [float], backendopt=False)
+        assert f(5.5e-309)
+
+
 def make_test_case((fnname, args, expected), dict):
     #
     def test_func(self):

diff --git a/pypy/translator/c/src/ll_math.c b/pypy/translator/c/src/ll_math.c
--- a/pypy/translator/c/src/ll_math.c
+++ b/pypy/translator/c/src/ll_math.c
@@ -22,12 +22,6 @@
 #endif
 #define PyPy_NAN (HUGE_VAL * 0.)
 
-int
-_pypy_math_isinf(double x)
-{
-    return PyPy_IS_INFINITY(x);
-}
-
 /* The following copyright notice applies to the original
    implementations of acosh, asinh and atanh. */
 

diff --git a/pypy/rpython/lltypesystem/module/ll_math.py b/pypy/rpython/lltypesystem/module/ll_math.py
--- a/pypy/rpython/lltypesystem/module/ll_math.py
+++ b/pypy/rpython/lltypesystem/module/ll_math.py
@@ -20,8 +20,7 @@
         separate_module_files=[cdir.join('src', 'll_math.c')],
         export_symbols=['_pypy_math_acosh', '_pypy_math_asinh',
                         '_pypy_math_atanh',
-                        '_pypy_math_expm1', '_pypy_math_log1p',
-                        '_pypy_math_isinf'],
+                        '_pypy_math_expm1', '_pypy_math_log1p'],
         )
     math_prefix = '_pypy_math_'
 else:
@@ -95,9 +94,9 @@
     # are awesome.
     return y != y
 
- at jit.purefunction
 def ll_math_isinf(y):
-    return bool(math_isinf(y))
+    # Use a bitwise OR so the JIT doesn't produce 2 different guards.
+    return (y == INFINITY) | (y == -INFINITY)
 
 
 ll_math_copysign = math_copysign