With flag optimize-constructed-arrays on, ARM and MIPS suffered a performance...

With flag optimize-constructed-arrays on, ARM and MIPS suffered a performance degrade due to incorrect code in GenerateRecordCallTarget().

The CL also enables flag optimize-constructed-arrays.

BUG=
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/14772043

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14692 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/code-stubs-arm.cc

@@ -4790,6 +4790,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   __ bind(&megamorphic);
   __ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
   __ str(ip, FieldMemOperand(r2, JSGlobalPropertyCell::kValueOffset));
+  __ jmp(&done);
 
   // An uninitialized cache is patched with the function or sentinel to
   // indicate the ElementsKind if function is the Array constructor.

src/flag-definitions.h

@@ -258,7 +258,7 @@ DEFINE_bool(unreachable_code_elimination, false,
             "eliminate unreachable code (hidden behind soft deopts)")
 DEFINE_bool(track_allocation_sites, true,
             "Use allocation site info to reduce transitions")
-DEFINE_bool(optimize_constructed_arrays, false,
+DEFINE_bool(optimize_constructed_arrays, true,
             "Use allocation site info on constructed arrays")
 DEFINE_bool(trace_osr, false, "trace on-stack replacement")
 DEFINE_int(stress_runs, 0, "number of stress runs")

src/mips/code-stubs-mips.cc

@@ -5158,6 +5158,7 @@ static void GenerateRecordCallTarget(MacroAssembler* masm) {
   __ bind(&megamorphic);
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
   __ sw(at, FieldMemOperand(a2, JSGlobalPropertyCell::kValueOffset));
+  __ jmp(&done);
 
   // An uninitialized cache is patched with the function or sentinel to
   // indicate the ElementsKind if function is the Array constructor.

test/mjsunit/allocation-site-info.js

@@ -28,10 +28,6 @@
 // Flags: --allow-natives-syntax --smi-only-arrays --expose-gc
 // Flags: --track-allocation-sites --noalways-opt
 
-// TODO(mvstanton): remove --nooptimize-constructed-arrays and enable
-// the constructed array code below when the feature is turned on
-// by default.
-
 // Test element kind of objects.
 // Since --smi-only-arrays affects builtins, its default setting at compile
 // time sticks if built with snapshot.  If --smi-only-arrays is deactivated
@@ -41,7 +37,7 @@
 
 // support_smi_only_arrays = %HasFastSmiElements(new Array(1,2,3,4,5,6,7,8));
 support_smi_only_arrays = true;
-optimize_constructed_arrays = false;
+optimize_constructed_arrays = true;
 
 if (support_smi_only_arrays) {
   print("Tests include smi-only arrays.");