Revert "Reland "[regalloc] Introduce deferred fixed ranges""

This reverts commit 1ca08865.

Reason for revert: Regressions across the board

Original change's description:
> Reland "[regalloc] Introduce deferred fixed ranges"
> 
> This is a reland of b1769313
> 
> Original change's description:
> > [regalloc] Introduce deferred fixed ranges
> > 
> > Fixed ranges are used to express register constraints in the
> > allocator. This change splits these fixed ranges into one for
> > normal code and deferred code. The former are handeled as before
> > whereas the latter are only made visible while allocating
> > registers for deferred code.
> > 
> > This prevents forward looking decisions in normal code to be
> > impacted by register constraints from deferred code.
> > 
> > Change-Id: I67d562bb41166194e62765d5ab051bc961054fc7
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1477742
> > Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> > Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> > Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#60322}
> 
> Change-Id: I1a31150256eb5608db985b144aab7ea457169d0d
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1530810
> Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#60364}

TBR=jarin@chromium.org,sigurds@chromium.org,herhut@chromium.org

Change-Id: Id8ad6c39774e38dd67decea997e08a4c58c452ec
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1532327Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60381}

src/compiler/backend/instruction.cc

@@ -651,11 +651,7 @@ std::ostream& operator<<(std::ostream& os,
   const InstructionSequence* code = printable_block.code_;
 
   os << "B" << block->rpo_number();
-  if (block->ao_number().IsValid()) {
-    os << ": AO#" << block->ao_number();
-  } else {
-    os << ": AO#?";
-  }
+  os << ": AO#" << block->ao_number();
   if (block->IsDeferred()) os << " (deferred)";
   if (!block->needs_frame()) os << " (no frame)";
   if (block->must_construct_frame()) os << " (construct frame)";

src/compiler/backend/live-range-separator.cc

@@ -162,7 +162,6 @@ void LiveRangeMerger::MarkRangesSpilledInDeferredBlocks() {
       }
     }
     if (child == nullptr) {
-      DCHECK(!data()->is_turbo_control_flow_aware_allocation());
       top->TreatAsSpilledInDeferredBlock(data()->allocation_zone(),
                                          code->InstructionBlockCount());
     }

src/compiler/pipeline.cc

@@ -401,12 +401,11 @@ class PipelineData {
   }
 
   void InitializeRegisterAllocationData(const RegisterConfiguration* config,
-                                        CallDescriptor* call_descriptor,
-                                        RegisterAllocationFlags flags) {
+                                        CallDescriptor* call_descriptor) {
     DCHECK_NULL(register_allocation_data_);
     register_allocation_data_ = new (register_allocation_zone())
         RegisterAllocationData(config, register_allocation_zone(), frame(),
-                               sequence(), flags, debug_name());
+                               sequence(), debug_name());
   }
 
   void InitializeOsrHelper() {
@@ -915,12 +914,6 @@ PipelineCompilationJob::Status PipelineCompilationJob::PrepareJobImpl(
   if (FLAG_inline_accessors) {
     compilation_info()->MarkAsAccessorInliningEnabled();
   }
-  if (FLAG_turbo_control_flow_aware_allocation) {
-    compilation_info()->MarkAsTurboControlFlowAwareAllocation();
-  }
-  if (FLAG_turbo_preprocess_ranges) {
-    compilation_info()->MarkAsTurboPreprocessRanges();
-  }
 
   // This is the bottleneck for computing and setting poisoning level in the
   // optimizing compiler.
@@ -2529,12 +2522,6 @@ bool Pipeline::AllocateRegistersForTesting(const RegisterConfiguration* config,
                                            bool run_verifier) {
   OptimizedCompilationInfo info(ArrayVector("testing"), sequence->zone(),
                                 Code::STUB);
-  if (FLAG_turbo_control_flow_aware_allocation) {
-    info.MarkAsTurboControlFlowAwareAllocation();
-  }
-  if (FLAG_turbo_preprocess_ranges) {
-    info.MarkAsTurboPreprocessRanges();
-  }
   ZoneStats zone_stats(sequence->isolate()->allocator());
   PipelineData data(&zone_stats, &info, sequence->isolate(), sequence);
   data.InitializeFrameData(nullptr);
@@ -2875,14 +2862,7 @@ void PipelineImpl::AllocateRegisters(const RegisterConfiguration* config,
   data_->sequence()->ValidateDeferredBlockExitPaths();
 #endif
 
-  RegisterAllocationFlags flags;
-  if (data->info()->is_turbo_control_flow_aware_allocation()) {
-    flags |= RegisterAllocationFlag::kTurboControlFlowAwareAllocation;
-  }
-  if (data->info()->is_turbo_preprocess_ranges()) {
-    flags |= RegisterAllocationFlag::kTurboPreprocessRanges;
-  }
-  data->InitializeRegisterAllocationData(config, call_descriptor, flags);
+  data->InitializeRegisterAllocationData(config, call_descriptor);
   if (info()->is_osr()) data->osr_helper()->SetupFrame(data->frame());
 
   Run<MeetRegisterConstraintsPhase>();
@@ -2903,7 +2883,7 @@ void PipelineImpl::AllocateRegisters(const RegisterConfiguration* config,
                                        data->register_allocation_data());
   }
 
-  if (info()->is_turbo_preprocess_ranges()) {
+  if (FLAG_turbo_preprocess_ranges) {
     Run<SplinterLiveRangesPhase>();
     if (info()->trace_turbo_json_enabled() &&
         !data->MayHaveUnverifiableGraph()) {
@@ -2919,7 +2899,7 @@ void PipelineImpl::AllocateRegisters(const RegisterConfiguration* config,
     Run<AllocateFPRegistersPhase<LinearScanAllocator>>();
   }
 
-  if (info()->is_turbo_preprocess_ranges()) {
+  if (FLAG_turbo_preprocess_ranges) {
     Run<MergeSplintersPhase>();
   }
 

src/optimized-compilation-info.h

@@ -55,9 +55,7 @@ class V8_EXPORT_PRIVATE OptimizedCompilationInfo final {
     kTraceTurboJson = 1 << 14,
     kTraceTurboGraph = 1 << 15,
     kTraceTurboScheduled = 1 << 16,
-    kWasmRuntimeExceptionSupport = 1 << 17,
-    kTurboControlFlowAwareAllocation = 1 << 18,
-    kTurboPreprocessRanges = 1 << 19
+    kWasmRuntimeExceptionSupport = 1 << 17
   };
 
   // Construct a compilation info for optimized compilation.
@@ -86,18 +84,6 @@ class V8_EXPORT_PRIVATE OptimizedCompilationInfo final {
 
   // Flags used by optimized compilation.
 
-  void MarkAsTurboControlFlowAwareAllocation() {
-    SetFlag(kTurboControlFlowAwareAllocation);
-  }
-  bool is_turbo_control_flow_aware_allocation() const {
-    return GetFlag(kTurboControlFlowAwareAllocation);
-  }
-
-  void MarkAsTurboPreprocessRanges() { SetFlag(kTurboPreprocessRanges); }
-  bool is_turbo_preprocess_ranges() const {
-    return GetFlag(kTurboPreprocessRanges);
-  }
-
   void MarkAsFunctionContextSpecializing() {
     SetFlag(kFunctionContextSpecializing);
   }

test/unittests/compiler/regalloc/register-allocator-unittest.cc

@@ -113,11 +113,6 @@ TEST_F(RegisterAllocatorTest, SimpleLoop) {
   // while(true) { i++ }
   StartBlock();
   auto i_reg = DefineConstant();
-  // Add a branch around the loop to ensure the end-block
-  // is connected.
-  EndBlock(Branch(Reg(DefineConstant()), 3, 1));
-
-  StartBlock();
   EndBlock();
 
   {
@@ -132,9 +127,6 @@ TEST_F(RegisterAllocatorTest, SimpleLoop) {
     EndLoop();
   }
 
-  StartBlock();
-  EndBlock();
-
   Allocate();
 }
 
@@ -625,10 +617,10 @@ TEST_F(RegisterAllocatorTest, SingleDeferredBlockSpill) {
 
   const int var_def_index = 1;
   const int call_index = 3;
-  const bool spill_in_deferred =
-      FLAG_turbo_preprocess_ranges || FLAG_turbo_control_flow_aware_allocation;
-  int expect_no_moves = spill_in_deferred ? var_def_index : call_index;
-  int expect_spill_move = spill_in_deferred ? call_index : var_def_index;
+  int expect_no_moves =
+      FLAG_turbo_preprocess_ranges ? var_def_index : call_index;
+  int expect_spill_move =
+      FLAG_turbo_preprocess_ranges ? call_index : var_def_index;
 
   // We should have no parallel moves at the "expect_no_moves" position.
   EXPECT_EQ(
@@ -693,67 +685,6 @@ TEST_F(RegisterAllocatorTest, MultipleDeferredBlockSpills) {
             GetParallelMoveCount(start_of_b3, Instruction::START, sequence()));
 }
 
-TEST_F(RegisterAllocatorTest, ValidMultipleDeferredBlockSpills) {
-  if (!FLAG_turbo_control_flow_aware_allocation) return;
-
-  StartBlock();  // B0
-  auto var1 = EmitOI(Reg(0));
-  auto var2 = EmitOI(Reg(1));
-  auto var3 = EmitOI(Reg(2));
-  EndBlock(Branch(Reg(var1, 0), 1, 2));
-
-  StartBlock(true);  // B1
-  EmitCall(Slot(-2), Slot(var1));
-  EndBlock(Jump(5));
-
-  StartBlock();  // B2
-  EmitNop();
-  EndBlock();
-
-  StartBlock();  // B3
-  EmitNop();
-  EndBlock(Branch(Reg(var2, 0), 1, 2));
-
-  StartBlock(true);  // B4
-  EmitCall(Slot(-1), Slot(var2));
-  EndBlock(Jump(2));
-
-  StartBlock();  // B5
-  EmitNop();
-  EndBlock();
-
-  StartBlock();  // B6
-  Return(Reg(var3, 2));
-  EndBlock();
-
-  const int def_of_v2 = 2;
-  const int call_in_b1 = 4;
-  const int call_in_b4 = 10;
-  const int end_of_b1 = 5;
-  const int end_of_b4 = 11;
-  const int start_of_b6 = 14;
-
-  Allocate();
-
-  const int var3_reg = 2;
-  const int var3_slot = 2;
-
-  EXPECT_FALSE(IsParallelMovePresent(def_of_v2, Instruction::START, sequence(),
-                                     Reg(var3_reg), Slot()));
-  EXPECT_TRUE(IsParallelMovePresent(call_in_b1, Instruction::START, sequence(),
-                                    Reg(var3_reg), Slot(var3_slot)));
-  EXPECT_TRUE(IsParallelMovePresent(end_of_b1, Instruction::START, sequence(),
-                                    Slot(var3_slot), Reg()));
-
-  EXPECT_TRUE(IsParallelMovePresent(call_in_b4, Instruction::START, sequence(),
-                                    Reg(var3_reg), Slot(var3_slot)));
-  EXPECT_TRUE(IsParallelMovePresent(end_of_b4, Instruction::START, sequence(),
-                                    Slot(var3_slot), Reg()));
-
-  EXPECT_EQ(0,
-            GetParallelMoveCount(start_of_b6, Instruction::START, sequence()));
-}
-
 namespace {
 
 enum class ParameterType { kFixedSlot, kSlot, kRegister, kFixedRegister };