[SCEV] Introduce ScalarEvolution::getOne and getZero.

Summary:
It is fairly common to call SE->getConstant(Ty, 0) or
SE->getConstant(Ty, 1); this change makes such uses a little bit
briefer.

I've refactored the call sites I could find easily to use getZero /
getOne.

Reviewers: hfinkel, majnemer, reames

Subscribers: sanjoy, llvm-commits

Differential Revision: http://reviews.llvm.org/D12947

llvm-svn: 248362

7 files changed, 9 insertions, 12 deletions

diff --git a/llvm/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp b/llvm/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
index 3c2c0cbc3d2..a13e552cbd0 100644
--- a/llvm/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
+++ b/llvm/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
@@ -270,7 +270,7 @@ bool AlignmentFromAssumptions::extractAlignmentInfo(CallInst *I,
   OffSCEV = nullptr;
   if (PtrToIntInst *PToI = dyn_cast<PtrToIntInst>(AndLHS)) {
     AAPtr = PToI->getPointerOperand();
-    OffSCEV = SE->getConstant(Int64Ty, 0);
+    OffSCEV = SE->getZero(Int64Ty);
   } else if (const SCEVAddExpr* AndLHSAddSCEV =
              dyn_cast<SCEVAddExpr>(AndLHSSCEV)) {
     // Try to find the ptrtoint; subtract it and the rest is the offset.
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index 54b6694c1ae..2f295fedf05 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -1796,7 +1796,7 @@ LinearFunctionTestReplace(Loop *L,
     // This addition may overflow, which is valid as long as the comparison is
     // truncated to BackedgeTakenCount->getType().
     IVCount = SE->getAddExpr(BackedgeTakenCount,
-                             SE->getConstant(BackedgeTakenCount->getType(), 1));
+                             SE->getOne(BackedgeTakenCount->getType()));
     // The BackedgeTaken expression contains the number of times that the
     // backedge branches to the loop header.  This is one less than the
     // number of times the loop executes, so use the incremented indvar.
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index b87af7cde51..f5b61edd5cc 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -531,7 +531,7 @@ bool LoopIdiomRecognize::processLoopStridedStore(
   BECount = SE->getTruncateOrZeroExtend(BECount, IntPtr);
 
   const SCEV *NumBytesS =
-      SE->getAddExpr(BECount, SE->getConstant(IntPtr, 1), SCEV::FlagNUW);
+      SE->getAddExpr(BECount, SE->getOne(IntPtr), SCEV::FlagNUW);
   if (StoreSize != 1) {
     NumBytesS = SE->getMulExpr(NumBytesS, SE->getConstant(IntPtr, StoreSize),
                                SCEV::FlagNUW);
@@ -635,7 +635,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(
   BECount = SE->getTruncateOrZeroExtend(BECount, IntPtrTy);
 
   const SCEV *NumBytesS =
-      SE->getAddExpr(BECount, SE->getConstant(IntPtrTy, 1), SCEV::FlagNUW);
+      SE->getAddExpr(BECount, SE->getOne(IntPtrTy), SCEV::FlagNUW);
   if (StoreSize != 1)
     NumBytesS = SE->getMulExpr(NumBytesS, SE->getConstant(IntPtrTy, StoreSize),
                                SCEV::FlagNUW);
diff --git a/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp b/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp
index d8c77f47c01..f007d6855a4 100644
--- a/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRerollPass.cpp
@@ -1487,8 +1487,7 @@ bool LoopReroll::runOnLoop(Loop *L, LPPassManager &LPM) {
     return Changed;
 
   const SCEV *LIBETC = SE->getBackedgeTakenCount(L);
-  const SCEV *IterCount =
-    SE->getAddExpr(LIBETC, SE->getConstant(LIBETC->getType(), 1));
+  const SCEV *IterCount = SE->getAddExpr(LIBETC, SE->getOne(LIBETC->getType()));
   DEBUG(dbgs() << "LRR: iteration count = " << *IterCount << "\n");
 
   // First, we need to find the induction variable with respect to which we can
diff --git a/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
index 913454bdfe8..1faa65eb341 100644
--- a/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/StraightLineStrengthReduce.cpp
@@ -524,7 +524,7 @@ void StraightLineStrengthReduce::allocateCandidatesAndFindBasisForGEP(
       continue;
 
     const SCEV *OrigIndexExpr = IndexExprs[I - 1];
-    IndexExprs[I - 1] = SE->getConstant(OrigIndexExpr->getType(), 0);
+    IndexExprs[I - 1] = SE->getZero(OrigIndexExpr->getType());
 
     // The base of this candidate is GEP's base plus the offsets of all
     // indices except this current one.
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 10554845e5a..cb481c13bab 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -253,8 +253,7 @@ void SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem,
     Rem->replaceAllUsesWith(Rem->getOperand(0));
   else {
     // (i+1) % n  -->  (i+1)==n?0:(i+1)  if i is in [0,n).
-    const SCEV *LessOne =
-      SE->getMinusSCEV(S, SE->getConstant(S->getType(), 1));
+    const SCEV *LessOne = SE->getMinusSCEV(S, SE->getOne(S->getType()));
     if (IsSigned && !SE->isKnownNonNegative(LessOne))
       return;
 
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 41cfd52c51b..bd381d31de7 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2625,9 +2625,8 @@ Value *InnerLoopVectorizer::getOrCreateTripCount(Loop *L) {
   BackedgeTakenCount = SE->getNoopOrZeroExtend(BackedgeTakenCount, IdxTy);
   
   // Get the total trip count from the count by adding 1.
-  const SCEV *ExitCount =
-    SE->getAddExpr(BackedgeTakenCount,
-                   SE->getConstant(BackedgeTakenCount->getType(), 1));
+  const SCEV *ExitCount = SE->getAddExpr(
+      BackedgeTakenCount, SE->getOne(BackedgeTakenCount->getType()));
 
   const DataLayout &DL = L->getHeader()->getModule()->getDataLayout();