MIPS: Simplify known successor block lowering.

src/mips/lithium-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "lithium-allocator-inl.h"
 #include "mips/lithium-mips.h"
 #include "mips/lithium-codegen-mips.h"
 #include "hydrogen-osr.h"
@@ skipping 831 matching lines @@
           LDummyUse(UseAny(current->OperandAt(0))));
     }
     for (int i = 1; i < current->OperandCount(); ++i) {
       if (current->OperandAt(i)->IsControlInstruction()) continue;
       LInstruction* dummy =
           new(zone()) LDummyUse(UseAny(current->OperandAt(i)));
       dummy->set_hydrogen_value(current);
       chunk_->AddInstruction(dummy, current_block_);
     }
   } else {
-    instr = current->CompileToLithium(this);
+    HBasicBlock* successor;
+    if (current->IsControlInstruction() &&
+        HControlInstruction::cast(current)->KnownSuccessorBlock(&successor) &&
+        successor != NULL) {
+      instr = new(zone()) LGoto(successor);
+    } else {
+      instr = current->CompileToLithium(this);
+    }
   }
 
   argument_count_ += current->argument_delta();
   ASSERT(argument_count_ >= 0);
 
   if (instr != NULL) {
     AddInstruction(instr, current);
   }
 
   current_instruction_ = old_current;
@@ skipping 65 matching lines @@
   }
 }
 
 
 LInstruction* LChunkBuilder::DoGoto(HGoto* instr) {
   return new(zone()) LGoto(instr->FirstSuccessor());
 }
 
 
 LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
-  LInstruction* goto_instr = CheckElideControlInstruction(instr);
-  if (goto_instr != NULL) return goto_instr;
-
   HValue* value = instr->value();
   Representation r = value->representation();
   HType type = value->type();
   ToBooleanStub::Types expected = instr->expected_input_types();
   if (expected.IsEmpty()) expected = ToBooleanStub::Types::Generic();
 
   bool easy_case = !r.IsTagged() || type.IsBoolean() || type.IsSmi() ||
       type.IsJSArray() || type.IsHeapNumber() || type.IsString();
   LInstruction* branch = new(zone()) LBranch(UseRegister(value));
   if (!easy_case &&
       ((!expected.Contains(ToBooleanStub::SMI) && expected.NeedsMap()) ||
        !expected.IsGeneric())) {
     branch = AssignEnvironment(branch);
   }
   return branch;
 }
 
 
 LInstruction* LChunkBuilder::DoCompareMap(HCompareMap* instr) {
-  LInstruction* goto_instr = CheckElideControlInstruction(instr);
-  if (goto_instr != NULL) return goto_instr;
-
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* value = UseRegisterAtStart(instr->value());
   LOperand* temp = TempRegister();
   return new(zone()) LCmpMapAndBranch(value, temp);
 }
 
 
 LInstruction* LChunkBuilder::DoArgumentsLength(HArgumentsLength* length) {
   info()->MarkAsRequiresFrame();
   return DefineAsRegister(
@@ skipping 648 matching lines @@
   LOperand* context = UseFixed(instr->context(), cp);
   LOperand* left = UseFixed(instr->left(), a1);
   LOperand* right = UseFixed(instr->right(), a0);
   LCmpT* result = new(zone()) LCmpT(context, left, right);
   return MarkAsCall(DefineFixed(result, v0), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareNumericAndBranch(
     HCompareNumericAndBranch* instr) {
-  LInstruction* goto_instr = CheckElideControlInstruction(instr);
-  if (goto_instr != NULL) return goto_instr;
   Representation r = instr->representation();
   if (r.IsSmiOrInteger32()) {
     ASSERT(instr->left()->representation().Equals(r));
     ASSERT(instr->right()->representation().Equals(r));
     LOperand* left = UseRegisterOrConstantAtStart(instr->left());
     LOperand* right = UseRegisterOrConstantAtStart(instr->right());
     return new(zone()) LCompareNumericAndBranch(left, right);
   } else {
     ASSERT(r.IsDouble());
     ASSERT(instr->left()->representation().IsDouble());
     ASSERT(instr->right()->representation().IsDouble());
     LOperand* left = UseRegisterAtStart(instr->left());
     LOperand* right = UseRegisterAtStart(instr->right());
     return new(zone()) LCompareNumericAndBranch(left, right);
   }
 }
 
 
 LInstruction* LChunkBuilder::DoCompareObjectEqAndBranch(
     HCompareObjectEqAndBranch* instr) {
-  LInstruction* goto_instr = CheckElideControlInstruction(instr);
-  if (goto_instr != NULL) return goto_instr;
   LOperand* left = UseRegisterAtStart(instr->left());
   LOperand* right = UseRegisterAtStart(instr->right());
   return new(zone()) LCmpObjectEqAndBranch(left, right);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareHoleAndBranch(
     HCompareHoleAndBranch* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   return new(zone()) LCmpHoleAndBranch(value);
 }
 
 
 LInstruction* LChunkBuilder::DoCompareMinusZeroAndBranch(
     HCompareMinusZeroAndBranch* instr) {
-  LInstruction* goto_instr = CheckElideControlInstruction(instr);
-  if (goto_instr != NULL) return goto_instr;
   LOperand* value = UseRegister(instr->value());
   LOperand* scratch = TempRegister();
   return new(zone()) LCompareMinusZeroAndBranch(value, scratch);
 }
 
 
 LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* temp = TempRegister();
   return new(zone()) LIsObjectAndBranch(UseRegisterAtStart(instr->value()),
@@ skipping 744 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoTypeof(HTypeof* instr) {
   LOperand* context = UseFixed(instr->context(), cp);
   LTypeof* result = new(zone()) LTypeof(context, UseFixed(instr->value(), a0));
   return MarkAsCall(DefineFixed(result, v0), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoTypeofIsAndBranch(HTypeofIsAndBranch* instr) {
-  LInstruction* goto_instr = CheckElideControlInstruction(instr);
-  if (goto_instr != NULL) return goto_instr;
-
   return new(zone()) LTypeofIsAndBranch(UseTempRegister(instr->value()));
 }
 
 
 LInstruction* LChunkBuilder::DoIsConstructCallAndBranch(
     HIsConstructCallAndBranch* instr) {
   return new(zone()) LIsConstructCallAndBranch(TempRegister());
 }
 
 
@@ skipping 79 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);
 }
 
 
 } }  // namespace v8::internal