[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

1 files changed, 14 insertions, 12 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);
   }