8-byte align C stack on Linux and Windows.

Review URL: http://codereview.chromium.org/42116

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1496 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-linux.cc

@@ -212,8 +212,8 @@ double OS::nan_value() {
 
 
 int OS::ActivationFrameAlignment() {
-  // No constraint on Linux.
-  return 0;
+  // Floating point code runs faster if the stack is 8-byte aligned.
+  return 8;
 }
 
 

src/platform-win32.cc

@@ -1298,8 +1298,8 @@ double OS::nan_value() {
 
 
 int OS::ActivationFrameAlignment() {
-  // No constraint on Windows.
-  return 0;
+  // Floating point code runs faster if the stack is 8-byte aligned.
+  return 8;
 }