[v8-dev] MIPS: Avoid unnecessary branches in array constructor stubs. (issue 107003008)

Thu, 02 Jan 2014 05:36:57 -0800 

Reviewers: danno, Benedikt Meurer, Paul Lind, kisg, palfia, dusmil,

Description:
MIPS: Avoid unnecessary branches in array constructor stubs.

Port r18427 (4db045a)

BUG=

Please review this at https://codereview.chromium.org/107003008/

SVN Base: https://github.com/v8/v8.git@gbl

Affected files (+19, -28 lines):
  M src/mips/code-stubs-mips.cc
  M src/mips/macro-assembler-mips.h
  M src/mips/macro-assembler-mips.cc


Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index 61e05f8fc8da57c3b18fd7a2a105ca3fc87b0e97..97ef020af5775649cb795488b16ecd604ec533a9 100644 
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -5683,12 +5683,9 @@ 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);
-      __ Branch(&next, ne, a3, Operand(kind));
       T stub(kind);
-      __ TailCallStub(&stub);
-      __ bind(&next);
+      __ TailCallStub(&stub, eq, a3, Operand(kind));
     }

     // If we reached this point there is a problem.
@@ -5764,12 +5761,9 @@ 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);
-      __ Branch(&next, ne, a3, Operand(kind));
       ArraySingleArgumentConstructorStub stub(kind);
-      __ TailCallStub(&stub);
-      __ bind(&next);
+      __ TailCallStub(&stub, eq, a3, Operand(kind));
     }

     // If we reached this point there is a problem.
@@ -5911,34 +5905,25 @@ void ArrayConstructorStub::Generate(MacroAssembler* masm) { 

 void InternalArrayConstructorStub::GenerateCase(
     MacroAssembler* masm, ElementsKind kind) {
-  Label not_zero_case, not_one_case;
-  Label normal_sequence;

-  __ Branch(&not_zero_case, ne, a0, Operand(zero_reg));
   InternalArrayNoArgumentConstructorStub stub0(kind);
-  __ TailCallStub(&stub0);
+  __ TailCallStub(&stub0, lo, a0, Operand(1));

-  __ bind(&not_zero_case);
-  __ Branch(&not_one_case, gt, a0, Operand(1));
+  InternalArrayNArgumentsConstructorStub stubN(kind);
+  __ TailCallStub(&stubN, hi, a0, Operand(1));

   if (IsFastPackedElementsKind(kind)) {
     // We might need to create a holey array
     // look at the first argument.
     __ lw(at, MemOperand(sp, 0));
-    __ Branch(&normal_sequence, eq, at, Operand(zero_reg));

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

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


Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc index 4e3ab3291be3fa3319b290762d01ba5eea3402b8..d67e58e660e8679a320957f9efdc522310632de4 100644 
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -3905,8 +3905,12 @@ void MacroAssembler::CallStub(CodeStub* stub,
 }


-void MacroAssembler::TailCallStub(CodeStub* stub) {
-  Jump(stub->GetCode(isolate()), RelocInfo::CODE_TARGET);
+void MacroAssembler::TailCallStub(CodeStub* stub,
+                                  Condition cond,
+                                  Register r1,
+                                  const Operand& r2,
+                                  BranchDelaySlot bd) {
+  Jump(stub->GetCode(isolate()), RelocInfo::CODE_TARGET, cond, r1, r2, bd);
 }


Index: src/mips/macro-assembler-mips.h
diff --git a/src/mips/macro-assembler-mips.h b/src/mips/macro-assembler-mips.h index f1b82ed0e5f16194a31a574cf391b5f75004eebf..4a7d9adf10eb37bf195de2840aa1488a70a3f198 100644 
--- a/src/mips/macro-assembler-mips.h
+++ b/src/mips/macro-assembler-mips.h
@@ -1194,16 +1194,18 @@ class MacroAssembler: public Assembler {
     li(s2, Operand(ref));
   }

+#define COND_ARGS Condition cond = al, Register rs = zero_reg, \
+const Operand& rt = Operand(zero_reg), BranchDelaySlot bd = PROTECT
+
   // Call a code stub.
   void CallStub(CodeStub* stub,
                 TypeFeedbackId ast_id = TypeFeedbackId::None(),
-                Condition cond = cc_always,
-                Register r1 = zero_reg,
-                const Operand& r2 = Operand(zero_reg),
-                BranchDelaySlot bd = PROTECT);
+                COND_ARGS);

   // Tail call a code stub (jump).
-  void TailCallStub(CodeStub* stub);
+  void TailCallStub(CodeStub* stub, COND_ARGS);
+
+#undef COND_ARGS

   void CallJSExitStub(CodeStub* stub);



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