Revert "Introduce Goto instructions to the flow graph."

runtime/vm/intermediate_language.cc

Index: runtime/vm/intermediate_language.cc
diff --git a/runtime/vm/intermediate_language.cc b/runtime/vm/intermediate_language.cc
index f250a5761ff8a421ae53a4f3974c22043f6e1634..8cc93e3e980e69d44179ac9d65a0f14058d86dec 100644
--- a/runtime/vm/intermediate_language.cc
+++ b/runtime/vm/intermediate_language.cc
@@ -258,22 +258,6 @@ void ThrowInstr::SetInputAt(intptr_t i, Value* value) {
 }
 
 
-intptr_t GotoInstr::InputCount() const {
-  return 0;
-}
-
-
-Value* GotoInstr::InputAt(intptr_t i) const {
-  UNREACHABLE();
-  return NULL;
-}
-
-
-void GotoInstr::SetInputAt(intptr_t i, Value* value) {
-  UNREACHABLE();
-}
-
-
 intptr_t ReturnInstr::InputCount() const {
   return 1;
 }
@@ -503,9 +487,7 @@ void BlockEntryInstr::DiscoverBlocks(
            !next_instr->IsBranch()) {
       if (vars != NULL) next_instr->RecordAssignedVars(vars);
       set_last_instruction(next_instr);
-      GotoInstr* goto_instr = next_instr->AsGoto();
-      next_instr =
-          (goto_instr != NULL) ? goto_instr->successor() : next_instr->next();
+      next_instr = next_instr->next();
     }
   }
   if (next_instr != NULL) {
@@ -557,15 +539,13 @@ void JoinEntryInstr::InsertPhi(intptr_t var_index, intptr_t var_count) {
 
 
 intptr_t Instruction::SuccessorCount() const {
-  return 0;
+  ASSERT(next() == NULL || next()->IsBlockEntry());
+  return (next() != NULL) ? 1 : 0;
 }
 
 
 BlockEntryInstr* Instruction::SuccessorAt(intptr_t index) const {
-  // Called only if index is in range.  Only control-transfer instructions
-  // can have non-zero successor counts and they override this function.
-  UNREACHABLE();
-  return NULL;
+  return next()->AsBlockEntry();
 }
 
 
@@ -593,22 +573,6 @@ BlockEntryInstr* BranchInstr::SuccessorAt(intptr_t index) const {
 }
 
 
-intptr_t GotoInstr::SuccessorCount() const {
-  return 1;
-}
-
-
-BlockEntryInstr* GotoInstr::SuccessorAt(intptr_t index) const {
-  ASSERT(index == 0);
-  return successor();
-}
-
-
-void Instruction::Goto(JoinEntryInstr* entry) {
-  set_next(new GotoInstr(entry));
-}
-
-
 // ==== Support for propagating static type.
 RawAbstractType* ConstantVal::StaticType() const {
   if (value().IsInstance()) {
@@ -1023,20 +987,6 @@ void ReThrowInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 }
 
 
-LocationSummary* GotoInstr::MakeLocationSummary() const {
-  return new LocationSummary(0, 0);
-}
-
-
-void GotoInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  // We can fall through if the successor is the next block in the list.
-  // Otherwise, we need a jump.
-  if (!compiler->IsNextBlock(successor())) {
-    __ jmp(compiler->GetBlockLabel(successor()));
-  }
-}
-
-
 LocationSummary* BranchInstr::MakeLocationSummary() const {
   if (is_fused_with_comparison()) {
     return fused_with_comparison_->locs();