Fix all the remaining lost-fast-math-flags bugs I've been able to find. The most important of these are cases in the generic logic for combining BinaryOperators.

This logic hadn't been updated to handle FastMathFlags, and it took me a while to detect it because it doesn't show up in a simple search for CreateFAdd.

llvm-svn: 199629

3 files changed, 49 insertions, 10 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 45db2468810..c56a31ce350 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -175,7 +175,7 @@ namespace {
     Value *createFDiv(Value *Opnd0, Value *Opnd1);
     Value *createFNeg(Value *V);
     Value *createNaryFAdd(const AddendVect& Opnds, unsigned InstrQuota);
-    void createInstPostProc(Instruction *NewInst);
+    void createInstPostProc(Instruction *NewInst, bool NoNumber = false);
 
     InstCombiner::BuilderTy *Builder;
     Instruction *Instr;
@@ -483,6 +483,11 @@ Value *FAddCombine::performFactorization(Instruction *I) {
   if (!Factor)
     return 0;
 
+  FastMathFlags Flags;
+  Flags.setUnsafeAlgebra();
+  if (I0) Flags &= I->getFastMathFlags();
+  if (I1) Flags &= I->getFastMathFlags();
+
   // Create expression "NewAddSub = AddSub0 +/- AddsSub1"
   Value *NewAddSub = (I->getOpcode() == Instruction::FAdd) ?
                       createFAdd(AddSub0, AddSub1) :
@@ -491,12 +496,20 @@ Value *FAddCombine::performFactorization(Instruction *I) {
     const APFloat &F = CFP->getValueAPF();
     if (!F.isNormal())
       return 0;
-  }
+  } else if (Instruction *II = dyn_cast<Instruction>(NewAddSub))
+    II->setFastMathFlags(Flags);
 
-  if (isMpy)
-    return createFMul(Factor, NewAddSub);
+  if (isMpy) {
+    Value *RI = createFMul(Factor, NewAddSub);
+    if (Instruction *II = dyn_cast<Instruction>(RI))
+      II->setFastMathFlags(Flags);
+    return RI;
+  }
 
-  return createFDiv(NewAddSub, Factor);
+  Value *RI = createFDiv(NewAddSub, Factor);
+  if (Instruction *II = dyn_cast<Instruction>(RI))
+    II->setFastMathFlags(Flags);
+  return RI;
 }
 
 Value *FAddCombine::simplify(Instruction *I) {
@@ -746,7 +759,10 @@ Value *FAddCombine::createFSub
 
 Value *FAddCombine::createFNeg(Value *V) {
   Value *Zero = cast<Value>(ConstantFP::get(V->getType(), 0.0));
-  return createFSub(Zero, V);
+  Value *NewV = createFSub(Zero, V);
+  if (Instruction *I = dyn_cast<Instruction>(NewV))
+    createInstPostProc(I, true); // fneg's don't receive instruction numbers.
+  return NewV;
 }
 
 Value *FAddCombine::createFAdd
@@ -771,11 +787,13 @@ Value *FAddCombine::createFDiv(Value *Opnd0, Value *Opnd1) {
   return V;
 }
 
-void FAddCombine::createInstPostProc(Instruction *NewInstr) {
+void FAddCombine::createInstPostProc(Instruction *NewInstr,
+                                     bool NoNumber) {
   NewInstr->setDebugLoc(Instr->getDebugLoc());
 
   // Keep track of the number of instruction created.
-  incCreateInstNum();
+  if (!NoNumber)
+    incCreateInstNum();
 
   // Propagate fast-math flags
   NewInstr->setFastMathFlags(Instr->getFastMathFlags());
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 738756a5a28..dd2089f3b72 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -1111,6 +1111,11 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
       //
       if (!isa<Constant>(Y) || !isa<Constant>(Op1)) {
         NewInst = Builder->CreateFMul(Y, Op1);
+        if (Instruction *RI = dyn_cast<Instruction>(NewInst)) {
+          FastMathFlags Flags = I.getFastMathFlags();
+          Flags &= cast<Instruction>(Op0)->getFastMathFlags();
+          RI->setFastMathFlags(Flags);
+        }
         SimpR = BinaryOperator::CreateFDiv(X, NewInst);
       }
     } else if (Op1->hasOneUse() && match(Op1, m_FDiv(m_Value(X), m_Value(Y)))) {
@@ -1118,6 +1123,11 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
       //
       if (!isa<Constant>(Y) || !isa<Constant>(Op0)) {
         NewInst = Builder->CreateFMul(Op0, Y);
+        if (Instruction *RI = dyn_cast<Instruction>(NewInst)) {
+          FastMathFlags Flags = I.getFastMathFlags();
+          Flags &= cast<Instruction>(Op1)->getFastMathFlags();
+          RI->setFastMathFlags(Flags);
+        }
         SimpR = BinaryOperator::CreateFDiv(NewInst, X);
       }
     }
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 191a101e0a3..6a7252fc41e 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -319,6 +319,12 @@ bool InstCombiner::SimplifyAssociativeOrCommutative(BinaryOperator &I) {
 
         Constant *Folded = ConstantExpr::get(Opcode, C1, C2);
         BinaryOperator *New = BinaryOperator::Create(Opcode, A, B);
+        if (isa<FPMathOperator>(New)) {
+          FastMathFlags Flags = I.getFastMathFlags();
+          Flags &= Op0->getFastMathFlags();
+          Flags &= Op1->getFastMathFlags();
+          New->setFastMathFlags(Flags);
+        }
         InsertNewInstWith(New, I);
         New->takeName(Op1);
         I.setOperand(0, New);
@@ -566,9 +572,14 @@ static Value *FoldOperationIntoSelectOperand(Instruction &I, Value *SO,
   if (!ConstIsRHS)
     std::swap(Op0, Op1);
 
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&I))
-    return IC->Builder->CreateBinOp(BO->getOpcode(), Op0, Op1,
+  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&I)) {
+    Value *RI = IC->Builder->CreateBinOp(BO->getOpcode(), Op0, Op1,
                                     SO->getName()+".op");
+    Instruction *FPInst = dyn_cast<Instruction>(RI);
+    if (FPInst && isa<FPMathOperator>(FPInst))
+      FPInst->copyFastMathFlags(BO);
+    return RI;
+  }
   if (ICmpInst *CI = dyn_cast<ICmpInst>(&I))
     return IC->Builder->CreateICmp(CI->getPredicate(), Op0, Op1,
                                    SO->getName()+".cmp");