LoopVectorize: Preserve debug location info

radar://14169017

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185122 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 74 insertions, 1 deletions

diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 579f20f181..5a37c0e1b4 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -326,6 +326,49 @@ private:
   EdgeMaskCache MaskCache;
 };
 
+/// \brief Set/reset the debug location in the IR builder using the RAII idiom.
+class DebugLocSetter {
+  IRBuilder<> &Builder;
+  DebugLoc OldDL;
+
+  DebugLocSetter(const DebugLocSetter&);
+  DebugLocSetter &operator=(const DebugLocSetter&);
+
+public:
+  /// \brief Set the debug location in the IRBuilder 'B' using the instruction
+  /// 'Inst'.
+  DebugLocSetter(IRBuilder<> &B, Instruction *Inst) : Builder(B) {
+    OldDL = Builder.getCurrentDebugLocation();
+    // Handle null instructions gracefully. This is so we can use a dyn_cast on
+    // values without nowing it is an instruction.
+    if (Inst)
+      Builder.SetCurrentDebugLocation(Inst->getDebugLoc());
+  }
+
+  ~DebugLocSetter() {
+    Builder.SetCurrentDebugLocation(OldDL);
+  }
+};
+
+/// \brief Look for a meaningful debug location on the instruction or it's
+/// operands.
+static Instruction *getDebugLocFromInstOrOperands(Instruction *I) {
+  if (!I)
+    return I;
+
+  DebugLoc Empty;
+  if (I->getDebugLoc() != Empty)
+    return I;
+
+  for (User::op_iterator OI = I->op_begin(), OE = I->op_end(); OI != OE; ++OI) {
+    if (Instruction *OpInst = dyn_cast<Instruction>(*OI))
+      if (OpInst->getDebugLoc() != Empty)
+        return OpInst;
+  }
+
+  return I;
+}
+
 /// \brief Check if conditionally executed loads are hoistable.
 ///
 /// This class has two functions: isHoistableLoad and canHoistAllLoads.
@@ -1195,6 +1238,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
   // Handle consecutive loads/stores.
   GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(Ptr);
   if (Gep && Legal->isInductionVariable(Gep->getPointerOperand())) {
+    DebugLocSetter SetDL(Builder, Gep);
     Value *PtrOperand = Gep->getPointerOperand();
     Value *FirstBasePtr = getVectorValue(PtrOperand)[0];
     FirstBasePtr = Builder.CreateExtractElement(FirstBasePtr, Zero);
@@ -1205,6 +1249,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
     Gep2->setName("gep.indvar.base");
     Ptr = Builder.Insert(Gep2);
   } else if (Gep) {
+    DebugLocSetter SetDL(Builder, Gep);
     assert(SE->isLoopInvariant(SE->getSCEV(Gep->getPointerOperand()),
                                OrigLoop) && "Base ptr must be invariant");
 
@@ -1237,6 +1282,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
   } else {
     // Use the induction element ptr.
     assert(isa<PHINode>(Ptr) && "Invalid induction ptr");
+    DebugLocSetter SetDL(Builder, cast<Instruction>(Ptr));
     VectorParts &PtrVal = getVectorValue(Ptr);
     Ptr = Builder.CreateExtractElement(PtrVal[0], Zero);
   }
@@ -1245,6 +1291,7 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
   if (SI) {
     assert(!Legal->isUniform(SI->getPointerOperand()) &&
            "We do not allow storing to uniform addresses");
+    DebugLocSetter SetDL(Builder, SI);
     // We don't want to update the value in the map as it might be used in
     // another expression. So don't use a reference type for "StoredVal".
     VectorParts StoredVal = getVectorValue(SI->getValueOperand());
@@ -1269,6 +1316,9 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr,
     return;
   }
 
+  // Handle loads.
+  assert(LI && "Must have a load instruction");
+  DebugLocSetter SetDL(Builder, LI);
   for (unsigned Part = 0; Part < UF; ++Part) {
     // Calculate the pointer for the specific unroll-part.
     Value *PartPtr = Builder.CreateGEP(Ptr, Builder.getInt32(Part * VF));
@@ -1292,6 +1342,8 @@ void InnerLoopVectorizer::scalarizeInstruction(Instruction *Instr) {
   // Holds vector parameters or scalars, in case of uniform vals.
   SmallVector<VectorParts, 4> Params;
 
+  DebugLocSetter SetDL(Builder, Instr);
+
   // Find all of the vectorized parameters.
   for (unsigned op = 0, e = Instr->getNumOperands(); op != e; ++op) {
     Value *SrcOp = Instr->getOperand(op);
@@ -1519,6 +1571,7 @@ InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) {
   Builder.SetInsertPoint(VecBody->getFirstInsertionPt());
 
   // Generate the induction variable.
+  DebugLocSetter SetDL(Builder, getDebugLocFromInstOrOperands(OldInduction));
   Induction = Builder.CreatePHI(IdxTy, 2, "index");
   // The loop step is equal to the vectorization factor (num of SIMD elements)
   // times the unroll factor (num of SIMD instructions).
@@ -1527,6 +1580,8 @@ InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) {
   // This is the IR builder that we use to add all of the logic for bypassing
   // the new vector loop.
   IRBuilder<> BypassBuilder(BypassBlock->getTerminator());
+  DebugLocSetter SetDLByPass(BypassBuilder,
+                             getDebugLocFromInstOrOperands(OldInduction));
 
   // We may need to extend the index in case there is a type mismatch.
   // We know that the count starts at zero and does not overflow.
@@ -2066,6 +2121,8 @@ InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
     for (unsigned part = 0; part < UF; ++part) {
       // This PHINode contains the vectorized reduction variable, or
       // the initial value vector, if we bypass the vector loop.
+      DebugLocSetter SetDL(Builder, RdxDesc.LoopExitInstr);
+
       VectorParts &RdxExitVal = getVectorValue(RdxDesc.LoopExitInstr);
       PHINode *NewPhi = Builder.CreatePHI(VecTy, 2, "rdx.vec.exit.phi");
       Value *StartVal = (part == 0) ? VectorStart : Identity;
@@ -2079,6 +2136,8 @@ InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
     Value *ReducedPartRdx = RdxParts[0];
     unsigned Op = getReductionBinOp(RdxDesc.Kind);
     for (unsigned part = 1; part < UF; ++part) {
+      DebugLocSetter SetDL(Builder, dyn_cast<Instruction>(RdxParts[part]));
+
       if (Op != Instruction::ICmp && Op != Instruction::FCmp)
         ReducedPartRdx = Builder.CreateBinOp((Instruction::BinaryOps)Op,
                                              RdxParts[part], ReducedPartRdx,
@@ -2096,6 +2155,7 @@ InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
     Value *TmpVec = ReducedPartRdx;
     SmallVector<Constant*, 32> ShuffleMask(VF, 0);
     for (unsigned i = VF; i != 1; i >>= 1) {
+      DebugLocSetter SetDL(Builder, dyn_cast<Instruction>(ReducedPartRdx));
       // Move the upper half of the vector to the lower half.
       for (unsigned j = 0; j != i/2; ++j)
         ShuffleMask[j] = Builder.getInt32(i/2 + j);
@@ -2118,7 +2178,11 @@ InnerLoopVectorizer::vectorizeLoop(LoopVectorizationLegality *Legal) {
     }
 
     // The result is in the first element of the vector.
-    Value *Scalar0 = Builder.CreateExtractElement(TmpVec, Builder.getInt32(0));
+    Value *Scalar0;
+    {
+      DebugLocSetter SetDL(Builder, dyn_cast<Instruction>(ReducedPartRdx));
+      Scalar0 = Builder.CreateExtractElement(TmpVec, Builder.getInt32(0));
+    }
 
     // Now, we need to fix the users of the reduction variable
     // inside and outside of the scalar remainder loop.
@@ -2253,6 +2317,7 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
 
       // Check for PHI nodes that are lowered to vector selects.
       if (P->getParent() != OrigLoop->getHeader()) {
+        DebugLocSetter SetDL(Builder, P);
         // We know that all PHIs in non header blocks are converted into
         // selects, so we don't have to worry about the insertion order and we
         // can just use the builder.
@@ -2295,6 +2360,8 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
       LoopVectorizationLegality::InductionInfo II =
         Legal->getInductionVars()->lookup(P);
 
+      DebugLocSetter SetDL(Builder, P);
+
       switch (II.IK) {
       case LoopVectorizationLegality::IK_NoInduction:
         llvm_unreachable("Unknown induction");
@@ -2402,6 +2469,7 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
     case Instruction::Xor: {
       // Just widen binops.
       BinaryOperator *BinOp = dyn_cast<BinaryOperator>(it);
+      DebugLocSetter SetDL(Builder, BinOp);
       VectorParts &A = getVectorValue(it->getOperand(0));
       VectorParts &B = getVectorValue(it->getOperand(1));
 
@@ -2428,6 +2496,7 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
       // instruction with a scalar condition. Otherwise, use vector-select.
       bool InvariantCond = SE->isLoopInvariant(SE->getSCEV(it->getOperand(0)),
                                                OrigLoop);
+      DebugLocSetter SetDL(Builder, it);
 
       // The condition can be loop invariant  but still defined inside the
       // loop. This means that we can't just use the original 'cond' value.
@@ -2452,6 +2521,7 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
       // Widen compares. Generate vector compares.
       bool FCmp = (it->getOpcode() == Instruction::FCmp);
       CmpInst *Cmp = dyn_cast<CmpInst>(it);
+      DebugLocSetter SetDL(Builder, it);
       VectorParts &A = getVectorValue(it->getOperand(0));
       VectorParts &B = getVectorValue(it->getOperand(1));
       for (unsigned Part = 0; Part < UF; ++Part) {
@@ -2482,6 +2552,7 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
     case Instruction::FPTrunc:
     case Instruction::BitCast: {
       CastInst *CI = dyn_cast<CastInst>(it);
+      DebugLocSetter SetDL(Builder, it);
       /// Optimize the special case where the source is the induction
       /// variable. Notice that we can only optimize the 'trunc' case
       /// because: a. FP conversions lose precision, b. sext/zext may wrap,
@@ -2509,6 +2580,8 @@ InnerLoopVectorizer::vectorizeBlockInLoop(LoopVectorizationLegality *Legal,
       if (isa<DbgInfoIntrinsic>(it))
         break;
 
+      DebugLocSetter SetDL(Builder, it);
+
       Module *M = BB->getParent()->getParent();
       CallInst *CI = cast<CallInst>(it);
       Intrinsic::ID ID = getIntrinsicIDForCall(CI, TLI);