[v8-dev] [arm] Avoid unnecessary branches in array constructor stubs. (issue 113863002)

[bmeurer]

Reviewers: ulan, Rodolph Perfetta,

Message:
Hey Ulan,
Here's another one to avoid unnecessary branches in code stubs.
PTAL
-- Benedikt
Description:
[arm] Avoid unnecessary branches in array constructor stubs.

Please review this at https://codereview.chromium.org/113863002/

SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge

Affected files (+6, -22 lines):
  M src/arm/code-stubs-arm.cc


Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index  
4eb08a1eebb0d7b0145166244f28414b497f604c..4fb6178897a2a0ceba89a2e7b8cf6d5c64bd057a  
100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -5705,13 +5705,10 @@ static void CreateArrayDispatch(MacroAssembler*  
masm,
     int last_index = GetSequenceIndexFromFastElementsKind(
         TERMINAL_FAST_ELEMENTS_KIND);
     for (int i = 0; i <= last_index; ++i) {
-      Label next;
       ElementsKind kind = GetFastElementsKindFromSequenceIndex(i);
       __ cmp(r3, Operand(kind));
-      __ b(ne, &next);
       T stub(kind);
-      __ TailCallStub(&stub);
-      __ bind(&next);
+      __ TailCallStub(&stub, eq);
     }

     // If we reached this point there is a problem.
@@ -5787,13 +5784,10 @@ static void  
CreateArrayDispatchOneArgument(MacroAssembler* masm,
     int last_index = GetSequenceIndexFromFastElementsKind(
         TERMINAL_FAST_ELEMENTS_KIND);
     for (int i = 0; i <= last_index; ++i) {
-      Label next;
       ElementsKind kind = GetFastElementsKindFromSequenceIndex(i);
       __ cmp(r3, Operand(kind));
-      __ b(ne, &next);
       ArraySingleArgumentConstructorStub stub(kind);
-      __ TailCallStub(&stub);
-      __ bind(&next);
+      __ TailCallStub(&stub, eq);
     }

     // If we reached this point there is a problem.
@@ -5934,37 +5928,27 @@ void ArrayConstructorStub::Generate(MacroAssembler*  
masm) {

 void InternalArrayConstructorStub::GenerateCase(
     MacroAssembler* masm, ElementsKind kind) {
-  Label not_zero_case, not_one_case;
-  Label normal_sequence;
-
   __ tst(r0, r0);
-  __ b(ne, &not_zero_case);
   InternalArrayNoArgumentConstructorStub stub0(kind);
-  __ TailCallStub(&stub0);
+  __ TailCallStub(&stub0, eq);

-  __ bind(&not_zero_case);
   __ cmp(r0, Operand(1));
-  __ b(gt, &not_one_case);
+  InternalArrayNArgumentsConstructorStub stubN(kind);
+  __ TailCallStub(&stubN, gt);

   if (IsFastPackedElementsKind(kind)) {
     // We might need to create a holey array
     // look at the first argument
     __ ldr(r3, MemOperand(sp, 0));
     __ cmp(r3, Operand::Zero());
-    __ b(eq, &normal_sequence);

     InternalArraySingleArgumentConstructorStub
         stub1_holey(GetHoleyElementsKind(kind));
-    __ TailCallStub(&stub1_holey);
+    __ TailCallStub(&stub1_holey, ne);
   }

-  __ bind(&normal_sequence);
   InternalArraySingleArgumentConstructorStub stub1(kind);
   __ TailCallStub(&stub1);
-
-  __ bind(&not_one_case);
-  InternalArrayNArgumentsConstructorStub stubN(kind);
-  __ TailCallStub(&stubN);
 }




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