Improve the allocation and initialization of locals on IA32 in the top-level compiler.

This optimization is already done on x64 and ARM.

Until now we used a push immediate for each local variable on IA32:

  push $undefined
  push $undefined
  ...

to initialize each local variable. This change does:

  mov eax, $undefined
  push eax
  push eax
  ...

Review URL: http://codereview.chromium.org/393009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3304 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

diff --git a/src/ia32/fast-codegen-ia32.cc b/src/ia32/fast-codegen-ia32.cc
index c366b40..a01d754 100644 (file)
--- a/src/ia32/fast-codegen-ia32.cc
+++ b/src/ia32/fast-codegen-ia32.cc
@@ -62,8 +62,13 @@ void FastCodeGenerator::Generate(FunctionLiteral* fun) {
 
   { Comment cmnt(masm_, "[ Allocate locals");
     int locals_count = fun->scope()->num_stack_slots();
-    for (int i = 0; i < locals_count; i++) {
+    if (locals_count == 1) {
       __ push(Immediate(Factory::undefined_value()));
+    } else if (locals_count > 1) {
+      __ mov(eax, Immediate(Factory::undefined_value()));
+      for (int i = 0; i < locals_count; i++) {
+       __ push(eax);
+      }
     }
   }