[pypy-commit] cffi default: Issue #260: don't use "x << 0" but "x | 0" to check that x is an

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r2700:bc14c64da0f4
Date: 2016-05-30 08:39 +0200
http://bitbucket.org/cffi/cffi/changeset/bc14c64da0f4/

Log:	Issue #260: don't use "x << 0" but "x | 0" to check that x is an
	integer. It seems that "x << 0" is undefined, according to the C
	standard, if x is any negative value...

diff --git a/cffi/recompiler.py b/cffi/recompiler.py
--- a/cffi/recompiler.py
+++ b/cffi/recompiler.py
@@ -814,7 +814,7 @@
             try:
                 if ftype.is_integer_type() or fbitsize >= 0:
                     # accept all integers, but complain on float or double
-                    prnt("  (void)((p->%s) << 1);  /* check that '%s.%s' is "
+                    prnt("  (void)((p->%s) | 0);  /* check that '%s.%s' is "
                          "an integer */" % (fname, cname, fname))
                     continue
                 # only accept exactly the type declared, except that '[]'
@@ -991,7 +991,7 @@
             prnt('static int %s(unsigned long long *o)' % funcname)
             prnt('{')
             prnt('  int n = (%s) <= 0;' % (name,))
-            prnt('  *o = (unsigned long long)((%s) << 0);'
+            prnt('  *o = (unsigned long long)((%s) | 0);'
                  '  /* check that %s is an integer */' % (name, name))
             if check_value is not None:
                 if check_value > 0:
@@ -1250,7 +1250,7 @@
 
     def _emit_bytecode_UnknownIntegerType(self, tp, index):
         s = ('_cffi_prim_int(sizeof(%s), (\n'
-             '           ((%s)-1) << 0 /* check that %s is an integer type */\n'
+             '           ((%s)-1) | 0 /* check that %s is an integer type */\n'
              '         ) <= 0)' % (tp.name, tp.name, tp.name))
         self.cffi_types[index] = CffiOp(OP_PRIMITIVE, s)