Remove redundant loads in DoCheckMaps

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
===================================================================
--- src/arm/lithium-codegen-arm.cc	(revision 12764)
+++ src/arm/lithium-codegen-arm.cc	(working copy)
@@ -4828,13 +4828,12 @@
 }
 
 
-void LCodeGen::DoCheckMapCommon(Register reg,
-                                Register scratch,
+void LCodeGen::DoCheckMapCommon(Register scratch,

[danno, 2012/12/07 10:47:11]

can you please rename this to map_reg here and elsewhere to make it clear what
it is?

                                 Handle<Map> map,
                                 CompareMapMode mode,
                                 LEnvironment* env) {
   Label success;
-  __ CompareMap(reg, scratch, map, &success, mode);
+  __ CompareMap(scratch, map, &success, mode);
   DeoptimizeIf(ne, env);
   __ bind(&success);
 }
@@ -4848,13 +4847,14 @@
 
   Label success;
   SmallMapList* map_set = instr->hydrogen()->map_set();
+  __ ldr(scratch, FieldMemOperand(reg, HeapObject::kMapOffset));

[danno, 2012/12/07 10:47:11]

can you please rename this to map_reg here and elsewhere to make it clear what
it is?

   for (int i = 0; i < map_set->length() - 1; i++) {
     Handle<Map> map = map_set->at(i);
-    __ CompareMap(reg, scratch, map, &success, REQUIRE_EXACT_MAP);
+    __ CompareMap(scratch, map, &success, REQUIRE_EXACT_MAP);
     __ b(eq, &success);
   }
   Handle<Map> map = map_set->last();
-  DoCheckMapCommon(reg, scratch, map, REQUIRE_EXACT_MAP, instr->environment());
+  DoCheckMapCommon(scratch, map, REQUIRE_EXACT_MAP, instr->environment());
   __ bind(&success);
 }
 
@@ -4923,7 +4923,8 @@
 
   // Check prototype maps up to the holder.
   while (!current_prototype.is_identical_to(holder)) {
-    DoCheckMapCommon(temp1, temp2,
+    __ ldr(temp2, FieldMemOperand(temp1, HeapObject::kMapOffset));
+    DoCheckMapCommon(temp2,
                      Handle<Map>(current_prototype->map()),
                      ALLOW_ELEMENT_TRANSITION_MAPS, instr->environment());
     current_prototype =
@@ -4933,7 +4934,7 @@
   }
 
   // Check the holder map.
-  DoCheckMapCommon(temp1, temp2,
+  DoCheckMapCommon(temp2,
                    Handle<Map>(current_prototype->map()),
                    ALLOW_ELEMENT_TRANSITION_MAPS, instr->environment());
   DeoptimizeIf(ne, instr->environment());