1 files changed, 56 insertions, 18 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index dbef1ff2e739..af15e0c31b75 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -79,21 +79,23 @@ namespace {
 
     bool eliminateIdentitySCEV(Instruction *UseInst, Instruction *IVOperand);
     bool replaceIVUserWithLoopInvariant(Instruction *UseInst);
+    bool replaceFloatIVWithIntegerIV(Instruction *UseInst);
 
     bool eliminateOverflowIntrinsic(WithOverflowInst *WO);
     bool eliminateSaturatingIntrinsic(SaturatingInst *SI);
     bool eliminateTrunc(TruncInst *TI);
     bool eliminateIVUser(Instruction *UseInst, Instruction *IVOperand);
-    bool makeIVComparisonInvariant(ICmpInst *ICmp, Value *IVOperand);
-    void eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand);
-    void simplifyIVRemainder(BinaryOperator *Rem, Value *IVOperand,
+    bool makeIVComparisonInvariant(ICmpInst *ICmp, Instruction *IVOperand);
+    void eliminateIVComparison(ICmpInst *ICmp, Instruction *IVOperand);
+    void simplifyIVRemainder(BinaryOperator *Rem, Instruction *IVOperand,
                              bool IsSigned);
     void replaceRemWithNumerator(BinaryOperator *Rem);
     void replaceRemWithNumeratorOrZero(BinaryOperator *Rem);
     void replaceSRemWithURem(BinaryOperator *Rem);
     bool eliminateSDiv(BinaryOperator *SDiv);
-    bool strengthenOverflowingOperation(BinaryOperator *OBO, Value *IVOperand);
-    bool strengthenRightShift(BinaryOperator *BO, Value *IVOperand);
+    bool strengthenOverflowingOperation(BinaryOperator *OBO,
+                                        Instruction *IVOperand);
+    bool strengthenRightShift(BinaryOperator *BO, Instruction *IVOperand);
   };
 }
 
@@ -192,7 +194,7 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand)
 }
 
 bool SimplifyIndvar::makeIVComparisonInvariant(ICmpInst *ICmp,
-                                               Value *IVOperand) {
+                                               Instruction *IVOperand) {
   unsigned IVOperIdx = 0;
   ICmpInst::Predicate Pred = ICmp->getPredicate();
   if (IVOperand != ICmp->getOperand(0)) {
@@ -261,7 +263,8 @@ bool SimplifyIndvar::makeIVComparisonInvariant(ICmpInst *ICmp,
 
 /// SimplifyIVUsers helper for eliminating useless
 /// comparisons against an induction variable.
-void SimplifyIndvar::eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand) {
+void SimplifyIndvar::eliminateIVComparison(ICmpInst *ICmp,
+                                           Instruction *IVOperand) {
   unsigned IVOperIdx = 0;
   ICmpInst::Predicate Pred = ICmp->getPredicate();
   ICmpInst::Predicate OriginalPred = Pred;
@@ -372,7 +375,8 @@ void SimplifyIndvar::replaceRemWithNumeratorOrZero(BinaryOperator *Rem) {
 
 /// SimplifyIVUsers helper for eliminating useless remainder operations
 /// operating on an induction variable or replacing srem by urem.
-void SimplifyIndvar::simplifyIVRemainder(BinaryOperator *Rem, Value *IVOperand,
+void SimplifyIndvar::simplifyIVRemainder(BinaryOperator *Rem,
+                                         Instruction *IVOperand,
                                          bool IsSigned) {
   auto *NValue = Rem->getOperand(0);
   auto *DValue = Rem->getOperand(1);
@@ -673,6 +677,35 @@ bool SimplifyIndvar::replaceIVUserWithLoopInvariant(Instruction *I) {
   return true;
 }
 
+/// Eliminate redundant type cast between integer and float.
+bool SimplifyIndvar::replaceFloatIVWithIntegerIV(Instruction *UseInst) {
+  if (UseInst->getOpcode() != CastInst::SIToFP)
+    return false;
+
+  Value *IVOperand = UseInst->getOperand(0);
+  // Get the symbolic expression for this instruction.
+  ConstantRange IVRange = SE->getSignedRange(SE->getSCEV(IVOperand));
+  unsigned DestNumSigBits = UseInst->getType()->getFPMantissaWidth();
+  if (IVRange.getActiveBits() <= DestNumSigBits) {
+    for (User *U : UseInst->users()) {
+      // Match for fptosi of sitofp and with same type.
+      auto *CI = dyn_cast<FPToSIInst>(U);
+      if (!CI || IVOperand->getType() != CI->getType())
+        continue;
+
+      CI->replaceAllUsesWith(IVOperand);
+      DeadInsts.push_back(CI);
+      LLVM_DEBUG(dbgs() << "INDVARS: Replace IV user: " << *CI
+                        << " with: " << *IVOperand << '\n');
+
+      ++NumFoldedUser;
+      Changed = true;
+    }
+  }
+
+  return Changed;
+}
+
 /// Eliminate any operation that SCEV can prove is an identity function.
 bool SimplifyIndvar::eliminateIdentitySCEV(Instruction *UseInst,
                                            Instruction *IVOperand) {
@@ -718,18 +751,16 @@ bool SimplifyIndvar::eliminateIdentitySCEV(Instruction *UseInst,
 /// Annotate BO with nsw / nuw if it provably does not signed-overflow /
 /// unsigned-overflow.  Returns true if anything changed, false otherwise.
 bool SimplifyIndvar::strengthenOverflowingOperation(BinaryOperator *BO,
-                                                    Value *IVOperand) {
-  SCEV::NoWrapFlags Flags;
-  bool Deduced;
-  std::tie(Flags, Deduced) = SE->getStrengthenedNoWrapFlagsFromBinOp(
+                                                    Instruction *IVOperand) {
+  auto Flags = SE->getStrengthenedNoWrapFlagsFromBinOp(
       cast<OverflowingBinaryOperator>(BO));
 
-  if (!Deduced)
-    return Deduced;
+  if (!Flags)
+    return false;
 
-  BO->setHasNoUnsignedWrap(ScalarEvolution::maskFlags(Flags, SCEV::FlagNUW) ==
+  BO->setHasNoUnsignedWrap(ScalarEvolution::maskFlags(*Flags, SCEV::FlagNUW) ==
                            SCEV::FlagNUW);
-  BO->setHasNoSignedWrap(ScalarEvolution::maskFlags(Flags, SCEV::FlagNSW) ==
+  BO->setHasNoSignedWrap(ScalarEvolution::maskFlags(*Flags, SCEV::FlagNSW) ==
                          SCEV::FlagNSW);
 
   // The getStrengthenedNoWrapFlagsFromBinOp() check inferred additional nowrap
@@ -737,14 +768,14 @@ bool SimplifyIndvar::strengthenOverflowingOperation(BinaryOperator *BO,
   // forgetValue() here to make sure those flags also propagate to any other
   // SCEV expressions based on the addrec. However, this can have pathological
   // compile-time impact, see https://bugs.llvm.org/show_bug.cgi?id=50384.
-  return Deduced;
+  return true;
 }
 
 /// Annotate the Shr in (X << IVOperand) >> C as exact using the
 /// information from the IV's range. Returns true if anything changed, false
 /// otherwise.
 bool SimplifyIndvar::strengthenRightShift(BinaryOperator *BO,
-                                          Value *IVOperand) {
+                                          Instruction *IVOperand) {
   using namespace llvm::PatternMatch;
 
   if (BO->getOpcode() == Instruction::Shl) {
@@ -896,6 +927,13 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
       }
     }
 
+    // Try to use integer induction for FPToSI of float induction directly.
+    if (replaceFloatIVWithIntegerIV(UseInst)) {
+      // Re-queue the potentially new direct uses of IVOperand.
+      pushIVUsers(IVOperand, L, Simplified, SimpleIVUsers);
+      continue;
+    }
+
     CastInst *Cast = dyn_cast<CastInst>(UseInst);
     if (V && Cast) {
       V->visitCast(Cast);