Vendor import of stripped llvm trunk r375505, the last commit before thevendor/llvm/llvm-trunk-r375505vendor/llvm

upstream Subversion repository was made read-only, and the LLVM project
migrated to GitHub:

https://llvm.org/svn/llvm-project/llvm/trunk@375505

1 files changed, 65 insertions, 12 deletions

diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index cc753ce05313..0b9128a9f5a1 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -124,6 +124,50 @@ static Constant *getLogBase2(Type *Ty, Constant *C) {
   return ConstantVector::get(Elts);
 }
 
+// TODO: This is a specific form of a much more general pattern.
+//       We could detect a select with any binop identity constant, or we
+//       could use SimplifyBinOp to see if either arm of the select reduces.
+//       But that needs to be done carefully and/or while removing potential
+//       reverse canonicalizations as in InstCombiner::foldSelectIntoOp().
+static Value *foldMulSelectToNegate(BinaryOperator &I,
+                                    InstCombiner::BuilderTy &Builder) {
+  Value *Cond, *OtherOp;
+
+  // mul (select Cond, 1, -1), OtherOp --> select Cond, OtherOp, -OtherOp
+  // mul OtherOp, (select Cond, 1, -1) --> select Cond, OtherOp, -OtherOp
+  if (match(&I, m_c_Mul(m_OneUse(m_Select(m_Value(Cond), m_One(), m_AllOnes())),
+                        m_Value(OtherOp))))
+    return Builder.CreateSelect(Cond, OtherOp, Builder.CreateNeg(OtherOp));
+
+  // mul (select Cond, -1, 1), OtherOp --> select Cond, -OtherOp, OtherOp
+  // mul OtherOp, (select Cond, -1, 1) --> select Cond, -OtherOp, OtherOp
+  if (match(&I, m_c_Mul(m_OneUse(m_Select(m_Value(Cond), m_AllOnes(), m_One())),
+                        m_Value(OtherOp))))
+    return Builder.CreateSelect(Cond, Builder.CreateNeg(OtherOp), OtherOp);
+
+  // fmul (select Cond, 1.0, -1.0), OtherOp --> select Cond, OtherOp, -OtherOp
+  // fmul OtherOp, (select Cond, 1.0, -1.0) --> select Cond, OtherOp, -OtherOp
+  if (match(&I, m_c_FMul(m_OneUse(m_Select(m_Value(Cond), m_SpecificFP(1.0),
+                                           m_SpecificFP(-1.0))),
+                         m_Value(OtherOp)))) {
+    IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
+    Builder.setFastMathFlags(I.getFastMathFlags());
+    return Builder.CreateSelect(Cond, OtherOp, Builder.CreateFNeg(OtherOp));
+  }
+
+  // fmul (select Cond, -1.0, 1.0), OtherOp --> select Cond, -OtherOp, OtherOp
+  // fmul OtherOp, (select Cond, -1.0, 1.0) --> select Cond, -OtherOp, OtherOp
+  if (match(&I, m_c_FMul(m_OneUse(m_Select(m_Value(Cond), m_SpecificFP(-1.0),
+                                           m_SpecificFP(1.0))),
+                         m_Value(OtherOp)))) {
+    IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
+    Builder.setFastMathFlags(I.getFastMathFlags());
+    return Builder.CreateSelect(Cond, Builder.CreateFNeg(OtherOp), OtherOp);
+  }
+
+  return nullptr;
+}
+
 Instruction *InstCombiner::visitMul(BinaryOperator &I) {
   if (Value *V = SimplifyMulInst(I.getOperand(0), I.getOperand(1),
                                  SQ.getWithInstruction(&I)))
@@ -213,6 +257,9 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
   if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I))
     return FoldedMul;
 
+  if (Value *FoldedMul = foldMulSelectToNegate(I, Builder))
+    return replaceInstUsesWith(I, FoldedMul);
+
   // Simplify mul instructions with a constant RHS.
   if (isa<Constant>(Op1)) {
     // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
@@ -358,6 +405,9 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
   if (Instruction *FoldedMul = foldBinOpIntoSelectOrPhi(I))
     return FoldedMul;
 
+  if (Value *FoldedMul = foldMulSelectToNegate(I, Builder))
+    return replaceInstUsesWith(I, FoldedMul);
+
   // X * -1.0 --> -X
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
   if (match(Op1, m_SpecificFP(-1.0)))
@@ -373,16 +423,6 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
   if (match(Op0, m_FNeg(m_Value(X))) && match(Op1, m_Constant(C)))
     return BinaryOperator::CreateFMulFMF(X, ConstantExpr::getFNeg(C), &I);
 
-  // Sink negation: -X * Y --> -(X * Y)
-  // But don't transform constant expressions because there's an inverse fold.
-  if (match(Op0, m_OneUse(m_FNeg(m_Value(X)))) && !isa<ConstantExpr>(Op0))
-    return BinaryOperator::CreateFNegFMF(Builder.CreateFMulFMF(X, Op1, &I), &I);
-
-  // Sink negation: Y * -X --> -(X * Y)
-  // But don't transform constant expressions because there's an inverse fold.
-  if (match(Op1, m_OneUse(m_FNeg(m_Value(X)))) && !isa<ConstantExpr>(Op1))
-    return BinaryOperator::CreateFNegFMF(Builder.CreateFMulFMF(X, Op0, &I), &I);
-
   // fabs(X) * fabs(X) -> X * X
   if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::fabs>(m_Value(X))))
     return BinaryOperator::CreateFMulFMF(X, X, &I);
@@ -1211,8 +1251,8 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
         !IsTan && match(Op0, m_Intrinsic<Intrinsic::cos>(m_Value(X))) &&
                   match(Op1, m_Intrinsic<Intrinsic::sin>(m_Specific(X)));
 
-    if ((IsTan || IsCot) && hasUnaryFloatFn(&TLI, I.getType(), LibFunc_tan,
-                                            LibFunc_tanf, LibFunc_tanl)) {
+    if ((IsTan || IsCot) &&
+        hasFloatFn(&TLI, I.getType(), LibFunc_tan, LibFunc_tanf, LibFunc_tanl)) {
       IRBuilder<> B(&I);
       IRBuilder<>::FastMathFlagGuard FMFGuard(B);
       B.setFastMathFlags(I.getFastMathFlags());
@@ -1244,6 +1284,17 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
     return &I;
   }
 
+  // X / fabs(X) -> copysign(1.0, X)
+  // fabs(X) / X -> copysign(1.0, X)
+  if (I.hasNoNaNs() && I.hasNoInfs() &&
+      (match(&I,
+             m_FDiv(m_Value(X), m_Intrinsic<Intrinsic::fabs>(m_Deferred(X)))) ||
+       match(&I, m_FDiv(m_Intrinsic<Intrinsic::fabs>(m_Value(X)),
+                        m_Deferred(X))))) {
+    Value *V = Builder.CreateBinaryIntrinsic(
+        Intrinsic::copysign, ConstantFP::get(I.getType(), 1.0), X, &I);
+    return replaceInstUsesWith(I, V);
+  }
   return nullptr;
 }
 
@@ -1309,6 +1360,8 @@ Instruction *InstCombiner::visitURem(BinaryOperator &I) {
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
   Type *Ty = I.getType();
   if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/ true, 0, &I)) {
+    // This may increase instruction count, we don't enforce that Y is a
+    // constant.
     Constant *N1 = Constant::getAllOnesValue(Ty);
     Value *Add = Builder.CreateAdd(Op1, N1);
     return BinaryOperator::CreateAnd(Op0, Add);