[InstCombine] Cleanup the interface for overflow checks

Summary:
Fix naming conventions and const correctness.
This completes the changes made in rL303029.

Patch by Yoav Ben-Shalom.

Reviewers: craig.topper

Reviewed By: craig.topper

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D33377

llvm-svn: 303529

4 files changed, 50 insertions, 39 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index f32ee965397..733eeb1767a 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -852,8 +852,9 @@ Value *FAddCombine::createAddendVal(const FAddend &Opnd, bool &NeedNeg) {
 /// This basically requires proving that the add in the original type would not
 /// overflow to change the sign bit or have a carry out.
 /// TODO: Handle this for Vectors.
-bool InstCombiner::WillNotOverflowSignedSub(Value *LHS, Value *RHS,
-                                            Instruction &CxtI) {
+bool InstCombiner::willNotOverflowSignedSub(const Value *LHS,
+                                            const Value *RHS,
+                                            const Instruction &CxtI) const {
   // If LHS and RHS each have at least two sign bits, the subtraction
   // cannot overflow.
   if (ComputeNumSignBits(LHS, 0, &CxtI) > 1 &&
@@ -879,8 +880,9 @@ bool InstCombiner::WillNotOverflowSignedSub(Value *LHS, Value *RHS,
 
 /// \brief Return true if we can prove that:
 ///    (sub LHS, RHS)  === (sub nuw LHS, RHS)
-bool InstCombiner::WillNotOverflowUnsignedSub(Value *LHS, Value *RHS,
-                                              Instruction &CxtI) {
+bool InstCombiner::willNotOverflowUnsignedSub(const Value *LHS,
+                                              const Value *RHS,
+                                              const Instruction &CxtI) const {
   // If the LHS is negative and the RHS is non-negative, no unsigned wrap.
   KnownBits LHSKnown = computeKnownBits(LHS, /*Depth=*/0, &CxtI);
   KnownBits RHSKnown = computeKnownBits(RHS, /*Depth=*/0, &CxtI);
@@ -1180,7 +1182,7 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
         Constant *CI =
             ConstantExpr::getTrunc(RHSC, LHSConv->getOperand(0)->getType());
         if (ConstantExpr::getSExt(CI, I.getType()) == RHSC &&
-            WillNotOverflowSignedAdd(LHSConv->getOperand(0), CI, I)) {
+            willNotOverflowSignedAdd(LHSConv->getOperand(0), CI, I)) {
           // Insert the new, smaller add.
           Value *NewAdd =
               Builder->CreateNSWAdd(LHSConv->getOperand(0), CI, "addconv");
@@ -1197,7 +1199,7 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
       if (LHSConv->getOperand(0)->getType() ==
               RHSConv->getOperand(0)->getType() &&
           (LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
-          WillNotOverflowSignedAdd(LHSConv->getOperand(0),
+          willNotOverflowSignedAdd(LHSConv->getOperand(0),
                                    RHSConv->getOperand(0), I)) {
         // Insert the new integer add.
         Value *NewAdd = Builder->CreateNSWAdd(LHSConv->getOperand(0),
@@ -1275,10 +1277,10 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
     }
   }
 
-  // TODO(jingyue): Consider WillNotOverflowSignedAdd and
+  // TODO(jingyue): Consider willNotOverflowSignedAdd and
   // willNotOverflowUnsignedAdd to reduce the number of invocations of
   // computeKnownBits.
-  if (!I.hasNoSignedWrap() && WillNotOverflowSignedAdd(LHS, RHS, I)) {
+  if (!I.hasNoSignedWrap() && willNotOverflowSignedAdd(LHS, RHS, I)) {
     Changed = true;
     I.setHasNoSignedWrap(true);
   }
@@ -1351,7 +1353,7 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
           ConstantExpr::getFPToSI(CFP, LHSIntVal->getType());
         if (LHSConv->hasOneUse() &&
             ConstantExpr::getSIToFP(CI, I.getType()) == CFP &&
-            WillNotOverflowSignedAdd(LHSIntVal, CI, I)) {
+            willNotOverflowSignedAdd(LHSIntVal, CI, I)) {
           // Insert the new integer add.
           Value *NewAdd = Builder->CreateNSWAdd(LHSIntVal,
                                                 CI, "addconv");
@@ -1370,7 +1372,7 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
         // and if the integer add will not overflow.
         if (LHSIntVal->getType() == RHSIntVal->getType() &&
             (LHSConv->hasOneUse() || RHSConv->hasOneUse()) &&
-            WillNotOverflowSignedAdd(LHSIntVal, RHSIntVal, I)) {
+            willNotOverflowSignedAdd(LHSIntVal, RHSIntVal, I)) {
           // Insert the new integer add.
           Value *NewAdd = Builder->CreateNSWAdd(LHSIntVal,
                                                 RHSIntVal, "addconv");
@@ -1676,11 +1678,11 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) {
       return replaceInstUsesWith(I, Res);
 
   bool Changed = false;
-  if (!I.hasNoSignedWrap() && WillNotOverflowSignedSub(Op0, Op1, I)) {
+  if (!I.hasNoSignedWrap() && willNotOverflowSignedSub(Op0, Op1, I)) {
     Changed = true;
     I.setHasNoSignedWrap(true);
   }
-  if (!I.hasNoUnsignedWrap() && WillNotOverflowUnsignedSub(Op0, Op1, I)) {
+  if (!I.hasNoUnsignedWrap() && willNotOverflowUnsignedSub(Op0, Op1, I)) {
     Changed = true;
     I.setHasNoUnsignedWrap(true);
   }
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index e2729516b40..6492eaedae9 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -3506,7 +3506,7 @@ bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
     // We can strength reduce this signed add into a regular add if we can prove
     // that it will never overflow.
     if (OCF == OCF_SIGNED_ADD)
-      if (WillNotOverflowSignedAdd(LHS, RHS, OrigI))
+      if (willNotOverflowSignedAdd(LHS, RHS, OrigI))
         return SetResult(Builder->CreateNSWAdd(LHS, RHS), Builder->getFalse(),
                          true);
     break;
@@ -3519,11 +3519,11 @@ bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
       return SetResult(LHS, Builder->getFalse(), false);
 
     if (OCF == OCF_SIGNED_SUB) {
-      if (WillNotOverflowSignedSub(LHS, RHS, OrigI))
+      if (willNotOverflowSignedSub(LHS, RHS, OrigI))
         return SetResult(Builder->CreateNSWSub(LHS, RHS), Builder->getFalse(),
                          true);
     } else {
-      if (WillNotOverflowUnsignedSub(LHS, RHS, OrigI))
+      if (willNotOverflowUnsignedSub(LHS, RHS, OrigI))
         return SetResult(Builder->CreateNUWSub(LHS, RHS), Builder->getFalse(),
                          true);
     }
@@ -3553,7 +3553,7 @@ bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
       return SetResult(LHS, Builder->getFalse(), false);
 
     if (OCF == OCF_SIGNED_MUL)
-      if (WillNotOverflowSignedMul(LHS, RHS, OrigI))
+      if (willNotOverflowSignedMul(LHS, RHS, OrigI))
         return SetResult(Builder->CreateNSWMul(LHS, RHS), Builder->getFalse(),
                          true);
     break;
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index 4b683cb192d..6829be86885 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -406,18 +406,24 @@ private:
                                  bool DoTransform = true);
 
   Instruction *transformSExtICmp(ICmpInst *ICI, Instruction &CI);
-  bool WillNotOverflowSignedAdd(Value *LHS, Value *RHS, Instruction &CxtI) {
+  bool willNotOverflowSignedAdd(const Value *LHS, const Value *RHS,
+                                const Instruction &CxtI) const {
     return computeOverflowForSignedAdd(LHS, RHS, &CxtI) ==
            OverflowResult::NeverOverflows;
   };
-  bool willNotOverflowUnsignedAdd(Value *LHS, Value *RHS, Instruction &CxtI) {
+  bool willNotOverflowUnsignedAdd(const Value *LHS, const Value *RHS,
+                                  const Instruction &CxtI) const {
     return computeOverflowForUnsignedAdd(LHS, RHS, &CxtI) ==
            OverflowResult::NeverOverflows;
   };
-  bool WillNotOverflowSignedSub(Value *LHS, Value *RHS, Instruction &CxtI);
-  bool WillNotOverflowUnsignedSub(Value *LHS, Value *RHS, Instruction &CxtI);
-  bool WillNotOverflowSignedMul(Value *LHS, Value *RHS, Instruction &CxtI);
-  bool willNotOverflowUnsignedMul(Value *LHS, Value *RHS, Instruction &CxtI) {
+  bool willNotOverflowSignedSub(const Value *LHS, const Value *RHS,
+                                const Instruction &CxtI) const;
+  bool willNotOverflowUnsignedSub(const Value *LHS, const Value *RHS,
+                                  const Instruction &CxtI) const;
+  bool willNotOverflowSignedMul(const Value *LHS, const Value *RHS,
+                                const Instruction &CxtI) const;
+  bool willNotOverflowUnsignedMul(const Value *LHS, const Value *RHS,
+                                  const Instruction &CxtI) const {
     return computeOverflowForUnsignedMul(LHS, RHS, &CxtI) ==
            OverflowResult::NeverOverflows;
   };
@@ -525,29 +531,31 @@ public:
     return nullptr; // Don't do anything with FI
   }
 
-  void computeKnownBits(Value *V, KnownBits &Known,
-                        unsigned Depth, Instruction *CxtI) const {
+  void computeKnownBits(const Value *V, KnownBits &Known,
+                        unsigned Depth, const Instruction *CxtI) const {
     llvm::computeKnownBits(V, Known, DL, Depth, &AC, CxtI, &DT);
   }
-  KnownBits computeKnownBits(Value *V, unsigned Depth,
-                             Instruction *CxtI) const {
+  KnownBits computeKnownBits(const Value *V, unsigned Depth,
+                             const Instruction *CxtI) const {
     return llvm::computeKnownBits(V, DL, Depth, &AC, CxtI, &DT);
   }
 
-  bool MaskedValueIsZero(Value *V, const APInt &Mask, unsigned Depth = 0,
-                         Instruction *CxtI = nullptr) const {
+  bool MaskedValueIsZero(const Value *V, const APInt &Mask, unsigned Depth = 0,
+                         const Instruction *CxtI = nullptr) const {
     return llvm::MaskedValueIsZero(V, Mask, DL, Depth, &AC, CxtI, &DT);
   }
-  unsigned ComputeNumSignBits(Value *Op, unsigned Depth = 0,
-                              Instruction *CxtI = nullptr) const {
+  unsigned ComputeNumSignBits(const Value *Op, unsigned Depth = 0,
+                              const Instruction *CxtI = nullptr) const {
     return llvm::ComputeNumSignBits(Op, DL, Depth, &AC, CxtI, &DT);
   }
-  OverflowResult computeOverflowForUnsignedMul(Value *LHS, Value *RHS,
-                                               const Instruction *CxtI) {
+  OverflowResult computeOverflowForUnsignedMul(const Value *LHS,
+                                               const Value *RHS,
+                                               const Instruction *CxtI) const {
     return llvm::computeOverflowForUnsignedMul(LHS, RHS, DL, &AC, CxtI, &DT);
   }
-  OverflowResult computeOverflowForUnsignedAdd(Value *LHS, Value *RHS,
-                                               const Instruction *CxtI) {
+  OverflowResult computeOverflowForUnsignedAdd(const Value *LHS,
+                                               const Value *RHS,
+                                               const Instruction *CxtI) const {
     return llvm::computeOverflowForUnsignedAdd(LHS, RHS, DL, &AC, CxtI, &DT);
   }
   OverflowResult computeOverflowForSignedAdd(const Value *LHS,
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index 2a35259f210..fc13854f8fe 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -132,8 +132,9 @@ static Constant *getLogBase2Vector(ConstantDataVector *CV) {
 
 /// \brief Return true if we can prove that:
 ///    (mul LHS, RHS)  === (mul nsw LHS, RHS)
-bool InstCombiner::WillNotOverflowSignedMul(Value *LHS, Value *RHS,
-                                            Instruction &CxtI) {
+bool InstCombiner::willNotOverflowSignedMul(const Value *LHS,
+                                            const Value *RHS,
+                                            const Instruction &CxtI) const {
   // Multiplying n * m significant bits yields a result of n + m significant
   // bits. If the total number of significant bits does not exceed the
   // result bit width (minus 1), there is no overflow.
@@ -384,7 +385,7 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
         Constant *CI =
             ConstantExpr::getTrunc(Op1C, Op0Conv->getOperand(0)->getType());
         if (ConstantExpr::getSExt(CI, I.getType()) == Op1C &&
-            WillNotOverflowSignedMul(Op0Conv->getOperand(0), CI, I)) {
+            willNotOverflowSignedMul(Op0Conv->getOperand(0), CI, I)) {
           // Insert the new, smaller mul.
           Value *NewMul =
               Builder->CreateNSWMul(Op0Conv->getOperand(0), CI, "mulconv");
@@ -401,7 +402,7 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
       if (Op0Conv->getOperand(0)->getType() ==
               Op1Conv->getOperand(0)->getType() &&
           (Op0Conv->hasOneUse() || Op1Conv->hasOneUse()) &&
-          WillNotOverflowSignedMul(Op0Conv->getOperand(0),
+          willNotOverflowSignedMul(Op0Conv->getOperand(0),
                                    Op1Conv->getOperand(0), I)) {
         // Insert the new integer mul.
         Value *NewMul = Builder->CreateNSWMul(
@@ -447,7 +448,7 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
     }
   }
 
-  if (!I.hasNoSignedWrap() && WillNotOverflowSignedMul(Op0, Op1, I)) {
+  if (!I.hasNoSignedWrap() && willNotOverflowSignedMul(Op0, Op1, I)) {
     Changed = true;
     I.setHasNoSignedWrap(true);
   }