[turbofan] Initial version of allocation folding and write barrier elimination.

src/x87/builtins-x87.cc

Index: src/x87/builtins-x87.cc
diff --git a/src/x87/builtins-x87.cc b/src/x87/builtins-x87.cc
index 319f99a54f0620724fc7a7dcb986ac2c0037ff7f..a7f4edacc8a090fcf775221f1ed38452858901ba 100644
--- a/src/x87/builtins-x87.cc
+++ b/src/x87/builtins-x87.cc
@@ -2654,11 +2654,6 @@ void Builtins::Generate_AllocateInNewSpace(MacroAssembler* masm) {
   //  -- edx    : requested object size (untagged)
   //  -- esp[0] : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(edx, eax, ecx, edi, &runtime, NO_ALLOCATION_FLAGS);
-  __ Ret();
-
-  __ bind(&runtime);
   __ SmiTag(edx);
   __ PopReturnAddressTo(ecx);
   __ Push(edx);
@@ -2673,11 +2668,6 @@ void Builtins::Generate_AllocateInOldSpace(MacroAssembler* masm) {
   //  -- edx    : requested object size (untagged)
   //  -- esp[0] : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(edx, eax, ecx, edi, &runtime, PRETENURE);
-  __ Ret();
-
-  __ bind(&runtime);
   __ SmiTag(edx);
   __ PopReturnAddressTo(ecx);
   __ Push(edx);