[turbofan] Relax dependencies due to deopt during instruction scheduling.

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2376963002
Cr-Commit-Position: refs/heads/master@{#39819}

src/compiler/ia32/instruction-scheduler-ia32.cc

@@ -28,8 +28,6 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kIA32Imul:
     case kIA32ImulHigh:
     case kIA32UmulHigh:
-    case kIA32Idiv:
-    case kIA32Udiv:
     case kIA32Not:
     case kIA32Neg:
     case kIA32Shl:
@@ -103,6 +101,12 @@ int InstructionScheduler::GetTargetInstructionFlags(
           ? kNoOpcodeFlags
           : kIsLoadOperation | kHasSideEffect;
 
+    case kIA32Idiv:
+    case kIA32Udiv:
+      return (instr->addressing_mode() == kMode_None)
+                 ? kMayNeedDeoptCheck
+                 : kMayNeedDeoptCheck | kIsLoadOperation | kHasSideEffect;
+
     case kIA32Movsxbl:
     case kIA32Movzxbl:
     case kIA32Movb:

src/compiler/instruction-scheduler.cc

@@ -136,9 +136,9 @@ void InstructionScheduler::AddInstruction(Instruction* instr) {
       last_live_in_reg_marker_->AddSuccessor(new_node);
     }
 
-    // Make sure that new instructions are not scheduled before the last
-    // deoptimization point.
-    if (last_deopt_ != nullptr) {
+    // Make sure that instructions are not scheduled before the last
+    // deoptimization point when they depend on it.
+    if ((last_deopt_ != nullptr) && DependsOnDeoptimization(instr)) {
       last_deopt_->AddSuccessor(new_node);
     }
 

src/compiler/instruction-scheduler.h

@@ -21,9 +21,12 @@ enum ArchOpcodeFlags {
   kHasSideEffect = 2,      // The instruction has some side effects (memory
                            // store, function call...)
   kIsLoadOperation = 4,    // The instruction is a memory load.
+  kMayNeedDeoptCheck = 8,  // The instruction might be associated with a deopt
+                           // check. This is the case of instruction which can
+                           // blow up with particular inputs (e.g.: division by
+                           // zero on Intel platforms).
 };
 
-
 class InstructionScheduler final : public ZoneObject {
  public:
   InstructionScheduler(Zone* zone, InstructionSequence* sequence);
@@ -155,12 +158,25 @@ class InstructionScheduler final : public ZoneObject {
   // Check whether the given instruction has side effects (e.g. function call,
   // memory store).
   bool HasSideEffect(const Instruction* instr) const {
-    return GetInstructionFlags(instr) & kHasSideEffect;
+    return (GetInstructionFlags(instr) & kHasSideEffect) != 0;
   }
 
   // Return true if the instruction is a memory load.
   bool IsLoadOperation(const Instruction* instr) const {
-    return GetInstructionFlags(instr) & kIsLoadOperation;
+    return (GetInstructionFlags(instr) & kIsLoadOperation) != 0;
+  }
+
+  // Return true if this instruction is usually associated with a deopt check
+  // to validate its input.
+  bool MayNeedDeoptCheck(const Instruction* instr) const {
+    return (GetInstructionFlags(instr) & kMayNeedDeoptCheck) != 0;
+  }
+
+  // Return true if the instruction cannot be moved before the last deopt
+  // point we encountered.
+  bool DependsOnDeoptimization(const Instruction* instr) const {
+    return MayNeedDeoptCheck(instr) || instr->IsDeoptimizeCall() ||
+           HasSideEffect(instr) || IsLoadOperation(instr);
   }
 
   // Identify nops used as a definition point for live-in registers at

src/compiler/x64/instruction-scheduler-x64.cc

@@ -36,10 +36,6 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kX64Imul32:
     case kX64ImulHigh32:
     case kX64UmulHigh32:
-    case kX64Idiv:
-    case kX64Idiv32:
-    case kX64Udiv:
-    case kX64Udiv32:
     case kX64Not:
     case kX64Not32:
     case kX64Neg:
@@ -133,6 +129,14 @@ int InstructionScheduler::GetTargetInstructionFlags(
           ? kNoOpcodeFlags
           : kIsLoadOperation | kHasSideEffect;
 
+    case kX64Idiv:
+    case kX64Idiv32:
+    case kX64Udiv:
+    case kX64Udiv32:
+      return (instr->addressing_mode() == kMode_None)
+                 ? kMayNeedDeoptCheck
+                 : kMayNeedDeoptCheck | kIsLoadOperation | kHasSideEffect;
+
     case kX64Movsxbl:
     case kX64Movzxbl:
     case kX64Movsxbq: