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

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index 024bd83570c42dbf0d27074a78329fb84320a46c..89fcef863f47af03248ba6e0d1f63288fe8bc8b8 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -2742,11 +2742,6 @@ void Builtins::Generate_AllocateInNewSpace(MacroAssembler* masm) {
   //  -- a0 : requested object size (untagged)
   //  -- ra : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(a0, v0, a1, a2, &runtime, NO_ALLOCATION_FLAGS);
-  __ Ret();
-
-  __ bind(&runtime);
   __ SmiTag(a0);
   __ Push(a0);
   __ Move(cp, Smi::FromInt(0));
@@ -2759,11 +2754,6 @@ void Builtins::Generate_AllocateInOldSpace(MacroAssembler* masm) {
   //  -- a0 : requested object size (untagged)
   //  -- ra : return address
   // -----------------------------------
-  Label runtime;
-  __ Allocate(a0, v0, a1, a2, &runtime, PRETENURE);
-  __ Ret();
-
-  __ bind(&runtime);
   __ SmiTag(a0);
   __ Move(a1, Smi::FromInt(AllocateTargetSpace::encode(OLD_SPACE)));
   __ Push(a0, a1);