[pypy-svn] pypy default: An experiemnt - for guards write a hint "branch unlikely taken". Let's see

[fijal]

Author: Maciej Fijalkowski <fijall at gmail.com>
Branch: 
Changeset: r43274:2e31ce2f1e90
Date: 2011-04-11 01:24 +0200
http://bitbucket.org/pypy/pypy/changeset/2e31ce2f1e90/

Log:	An experiemnt - for guards write a hint "branch unlikely taken".
	Let's see if it affects benchmarks at all

diff --git a/pypy/jit/backend/x86/assembler.py b/pypy/jit/backend/x86/assembler.py
--- a/pypy/jit/backend/x86/assembler.py
+++ b/pypy/jit/backend/x86/assembler.py
@@ -1849,6 +1849,9 @@
     def implement_guard(self, guard_token, condition=None):
         # These jumps are patched later.
         if condition:
+            if condition not in ['B', 'E', 'BE']:
+                # this is a hint "branch not taken
+                self.mc.writechar('\x2E')
             self.mc.J_il(rx86.Conditions[condition], 0)
         else:
             self.mc.JMP_l(0)