Nuke isSideEffectFree

We can now compute the same result with Inst.mayHaveSideEffects(). NFC.

Swift SVN r25742

include/swift/SILPasses/Utils/Local.h

@@ -64,9 +64,6 @@ namespace swift {
   /// dead when this instruction is removed.
   void eraseUsesOfInstruction(SILInstruction *Inst);
 
-  /// Does the passed in BuiltinInst have any side effects?
-  bool isSideEffectFree(BuiltinInst *FR);
-
   /// Does the passed in BuiltinInst touch memory at all?
   bool isReadNone(BuiltinInst *FR);
 

lib/SIL/SILInstruction.cpp

@@ -643,12 +643,18 @@ SILInstruction::MemoryBehavior SILInstruction::getMemoryBehavior() const {
 
     // Handle LLVM intrinsic functions.
     const IntrinsicInfo & IInfo = BI->getIntrinsicInfo();
-    if (IInfo.ID != llvm::Intrinsic::not_intrinsic)
+    if (IInfo.ID != llvm::Intrinsic::not_intrinsic) {
+      // Read-only.
+      if (IInfo.hasAttribute(llvm::Attribute::ReadOnly) &&
+          IInfo.hasAttribute(llvm::Attribute::NoUnwind))
+        return MemoryBehavior::MayRead;
+      // Read-none?
       return IInfo.hasAttribute(llvm::Attribute::ReadNone) &&
                      IInfo.hasAttribute(llvm::Attribute::NoUnwind)
                  ? MemoryBehavior::None
                  : MemoryBehavior::MayHaveSideEffects;
     }
+  }
 
   // Handle functions that have an effects attribute.
   if (auto *AI = dyn_cast<ApplyInst>(this))

lib/SILAnalysis/ARCAnalysis.cpp

@@ -92,7 +92,7 @@ static bool canApplyDecrementRefCount(BuiltinInst *BI, SILValue Ptr,
                                       AliasAnalysis *AA) {
   // If we have a builtin that is side effect free, we can commute the
   // builtin and the retain.
-  if (isSideEffectFree(BI))
+  if (!BI->mayHaveSideEffects())
     return false;
   
   return canApplyDecrementRefCount(BI->getArguments(), Ptr, AA);

lib/SILAnalysis/AliasAnalysis.cpp

@@ -728,7 +728,7 @@ MemBehavior MemoryBehaviorVisitor::visitBuiltinInst(BuiltinInst *BI) {
   }
 
   // If the builtin is side effect free, then it can only read memory.
-  if (isSideEffectFree(BI)) {
+  if (!BI->mayHaveSideEffects()) {
     DEBUG(llvm::dbgs() << "  Found apply of side effect free builtin. "
                           "Returning MayRead.\n");
     return MemBehavior::MayRead;

lib/SILPasses/ArrayBoundsCheckOpts.cpp

@@ -72,12 +72,6 @@ enum class ArrayBoundsEffect {
   kMayChangeAny  // Might change any array.
 };
 
-static bool mayHaveSideEffects(SILInstruction *I) {
-  if (auto *BI = dyn_cast<BuiltinInst>(I))
-    return !isSideEffectFree(BI);
-  return I->mayHaveSideEffects();
-}
-
 static SILValue getArrayStructPointer(ArrayCallKind K, SILValue Array) {
   assert(K != ArrayCallKind::kNone);
 
@@ -182,7 +176,7 @@ mayChangeArraySize(SILInstruction *I, ArrayCallKind &Kind, SILValue &Array,
     return ArrayBoundsEffect::kMayChangeArg;
   }
 
-  if (!mayHaveSideEffects(I))
+  if (!I->mayHaveSideEffects())
     return ArrayBoundsEffect::kNone;
 
   // A store to an alloc_stack can't possibly store to the array size which is

lib/SILPasses/COWArrayOpt.cpp

@@ -471,11 +471,8 @@ bool COWArrayOpt::isRetainReleasedBeforeMutate(SILInstruction *RetainInst,
 
       if (ArrayUserSet.count(II)) // May be an array mutation.
         break;
-    } else if (II->mayHaveSideEffects()) {
-      if (auto *BI = dyn_cast<BuiltinInst>(II))
-        if(isSideEffectFree(BI))
+    } else if (!II->mayHaveSideEffects()) {
       continue;
-      break;
     }
   }
   DEBUG(llvm::dbgs() << "    Skipping Array: retained in loop!\n    "
@@ -737,9 +734,6 @@ bool COWArrayOpt::hasLoopOnlyDestructorSafeArrayOperations() {
       // Instructions without side effects are safe.
       if (!Inst->mayHaveSideEffects())
         continue;
-      if (auto *BI = dyn_cast<BuiltinInst>(Inst))
-        if(isSideEffectFree(BI))
-          continue;
       if (isa<CondFailInst>(Inst))
         continue;
       if (isa<AllocationInst>(Inst) || isa<DeallocStackInst>(Inst))

lib/SILPasses/DeadCodeElimination.cpp

@@ -35,9 +35,6 @@ namespace {
 // FIXME: Reconcile the similarities between this and
 //        isInstructionTriviallyDead.
 static bool seemsUseful(SILInstruction *I) {
-  if (auto *BI = dyn_cast<BuiltinInst>(I))
-    return !isSideEffectFree(BI);
-
   if (I->mayHaveSideEffects())
     return true;
 

lib/SILPasses/DeadObjectElimination.cpp

@@ -154,15 +154,6 @@ static bool doesDestructorHaveSideEffects(AllocRefInst *ARI) {
         }
       }
 
-      // If I is an apply calling a builtin that does not have side effects, we
-      // can ignore it.
-      if (auto *BI = dyn_cast<BuiltinInst>(&I))
-        if (isSideEffectFree(BI)) {
-          DEBUG(llvm::dbgs() << "            SAFE! No side effect "
-                "builtin.\n");
-          continue;
-        }
-
       // Storing into the object can be ignored.
       if (auto *SI = dyn_cast<StoreInst>(&I))
         if (SI->getDest().stripAddressProjections().getDef() == Self) {

lib/SILPasses/LICM.cpp

@@ -79,13 +79,6 @@ static bool hasLoopInvariantOperands(SILInstruction *I, SILLoop *L) {
   });
 }
 
-static bool mayHaveSideEffects(SILInstruction *I) {
-  if (auto *BI = dyn_cast<BuiltinInst>(I))
-    return !isSideEffectFree(BI);
-
-  return I->mayHaveSideEffects();
-}
-
 static bool mayRead(SILInstruction *I) {
   if (auto *BI = dyn_cast<BuiltinInst>(I))
     return !isReadNone(BI);
@@ -159,7 +152,7 @@ static bool sinkCondFail(SILLoop *Loop) {
           CFs.clear();
           LIOfPair = nullptr;
         }
-      } else if (mayHaveSideEffects(&Inst)) {
+      } else if (Inst.mayHaveSideEffects()) {
         CFs.clear();
         LIOfPair = nullptr;
       }
@@ -208,7 +201,7 @@ static bool hoistInstructions(SILLoop *Loop, DominanceInfo *DT, SILLoopInfo *LI,
         // Remove clobbered loads we have seen before.
         removeWrittenTo(AA, SafeReads, &Inst);
 
-        if (mayHaveSideEffects(&Inst))
+        if (Inst.mayHaveSideEffects())
           Writes.push_back(&Inst);
       }
     }
@@ -256,7 +249,7 @@ static bool hoistInstructions(SILLoop *Loop, DominanceInfo *DT, SILLoopInfo *LI,
       // invariant. We must hoist them so that we preserve memory safety. A
       // cond_fail that would have protected (executed before) a memory access
       // must - after hoisting - also be executed before said access.
-      if (mayHaveSideEffects(Inst) && !isa<CondFailInst>(Inst)) {
+      if (Inst->mayHaveSideEffects() && !isa<CondFailInst>(Inst)) {
         DEBUG(llvm::dbgs() << " not side effect free\n");
         continue;
       }
@@ -317,7 +310,7 @@ static bool sinkFixLiftime(SILLoop *Loop, DominanceInfo *DomTree,
     for (auto &Inst : *BB) {
       if (auto FLI = dyn_cast<FixLifetimeInst>(&Inst)) {
         FixLifetimeInsts.push_back(FLI);
-      } else if (mayHaveSideEffects(&Inst) && !isa<LoadInst>(&Inst) &&
+      } else if (Inst.mayHaveSideEffects() && !isa<LoadInst>(&Inst) &&
                  !isa<StoreInst>(&Inst)) {
         DEBUG(llvm::errs() << " mayhavesideeffects because of" << Inst);
         DEBUG(Inst.getParent()->dump());

lib/SILPasses/SILCodeMotion.cpp

@@ -114,10 +114,6 @@ static bool canSinkInstruction(SILInstruction *Inst) {
 /// \brief Returns true if this instruction is a skip barrier, which means that
 /// we can't sink other instructions past it.
 static bool isSinkBarrier(SILInstruction *Inst) {
-  // We know that some calls do not have side effects.
-  if (auto *BI = dyn_cast<BuiltinInst>(Inst))
-    return !isSideEffectFree(BI);
-
   if (isa<TermInst>(Inst))
     return false;
 

lib/SILPasses/Utils/Local.cpp

@@ -28,26 +28,6 @@ using namespace swift;
 // Do we use array.props?
 static bool HaveArrayProperty = true;
 
-bool
-swift::isSideEffectFree(BuiltinInst *FR) {
-
-  // First, check if we are dealing with a swift builtin.
-  const BuiltinInfo &BInfo = FR->getBuiltinInfo();
-  if (BInfo.ID != BuiltinValueKind::None) {
-    return BInfo.isReadNone();
-  }
-
-  // Second, specialcase llvm intrinsic.
-  const IntrinsicInfo & IInfo = FR->getIntrinsicInfo();
-  if (IInfo.ID != llvm::Intrinsic::not_intrinsic) {
-    return ( (IInfo.hasAttribute(llvm::Attribute::ReadNone) ||
-              IInfo.hasAttribute(llvm::Attribute::ReadOnly)) &&
-            IInfo.hasAttribute(llvm::Attribute::NoUnwind) );
-  }
-
-  llvm_unreachable("All cases are covered.");
-}
-
 bool swift::isReadNone(BuiltinInst *FR) {
   // First, check if we are dealing with a swift builtin.
   const BuiltinInfo &BInfo = FR->getBuiltinInfo();
@@ -87,7 +67,7 @@ swift::isInstructionTriviallyDead(SILInstruction *I) {
     return false;
 
   if (auto *BI = dyn_cast<BuiltinInst>(I)) {
-    return isSideEffectFree(BI);
+    return !BI->mayHaveSideEffects();
   }
 
   // condfail instructions that obviously can't fail are dead.