[DependenceAnalysis] Refactor uses of getConstantPart. NFC.

Rather than checking for the SCEV type prior to calling
getContantPart, perform the checks in the function. This reduces
the number of places where the checks are needed.

Differential Revision: http://reviews.llvm.org/D19241

llvm-svn: 266759

1 files changed, 21 insertions, 36 deletions

diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 93828904760..54a56803ff4 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -2256,11 +2256,12 @@ bool DependenceAnalysis::testMIV(const SCEV *Src,
 // Given a product, e.g., 10*X*Y, returns the first constant operand,
 // in this case 10. If there is no constant part, returns NULL.
 static
-const SCEVConstant *getConstantPart(const SCEVMulExpr *Product) {
-  for (unsigned Op = 0, Ops = Product->getNumOperands(); Op < Ops; Op++) {
-    if (const SCEVConstant *Constant = dyn_cast<SCEVConstant>(Product->getOperand(Op)))
+const SCEVConstant *getConstantPart(const SCEV *Expr) {
+  if (const auto *Constant = dyn_cast<SCEVConstant>(Expr))
+    return Constant;
+  else if (const auto *Product = dyn_cast<SCEVMulExpr>(Expr))
+    if (const auto *Constant = dyn_cast<SCEVConstant>(Product->getOperand(0)))
       return Constant;
-  }
   return nullptr;
 }
 
@@ -2299,11 +2300,9 @@ bool DependenceAnalysis::gcdMIVtest(const SCEV *Src,
   while (const SCEVAddRecExpr *AddRec =
          dyn_cast<SCEVAddRecExpr>(Coefficients)) {
     const SCEV *Coeff = AddRec->getStepRecurrence(*SE);
-    const SCEVConstant *Constant = dyn_cast<SCEVConstant>(Coeff);
-    if (const SCEVMulExpr *Product = dyn_cast<SCEVMulExpr>(Coeff))
-      // If the coefficient is the product of a constant and other stuff,
-      // we can use the constant in the GCD computation.
-      Constant = getConstantPart(Product);
+    // If the coefficient is the product of a constant and other stuff,
+    // we can use the constant in the GCD computation.
+    const auto *Constant = getConstantPart(Coeff);
     if (!Constant)
       return false;
     APInt ConstCoeff = Constant->getAPInt();
@@ -2320,11 +2319,9 @@ bool DependenceAnalysis::gcdMIVtest(const SCEV *Src,
   while (const SCEVAddRecExpr *AddRec =
          dyn_cast<SCEVAddRecExpr>(Coefficients)) {
     const SCEV *Coeff = AddRec->getStepRecurrence(*SE);
-    const SCEVConstant *Constant = dyn_cast<SCEVConstant>(Coeff);
-    if (const SCEVMulExpr *Product = dyn_cast<SCEVMulExpr>(Coeff))
-      // If the coefficient is the product of a constant and other stuff,
-      // we can use the constant in the GCD computation.
-      Constant = getConstantPart(Product);
+    // If the coefficient is the product of a constant and other stuff,
+    // we can use the constant in the GCD computation.
+    const auto *Constant = getConstantPart(Coeff);
     if (!Constant)
       return false;
     APInt ConstCoeff = Constant->getAPInt();
@@ -2403,12 +2400,9 @@ bool DependenceAnalysis::gcdMIVtest(const SCEV *Src,
       if (CurLoop == AddRec->getLoop())
         ; // SrcCoeff == Coeff
       else {
-        if (const SCEVMulExpr *Product = dyn_cast<SCEVMulExpr>(Coeff))
-          // If the coefficient is the product of a constant and other stuff,
-          // we can use the constant in the GCD computation.
-          Constant = getConstantPart(Product);
-        else
-          Constant = cast<SCEVConstant>(Coeff);
+        // If the coefficient is the product of a constant and other stuff,
+        // we can use the constant in the GCD computation.
+        Constant = getConstantPart(Coeff);
         if (!Constant)
           return false;
         APInt ConstCoeff = Constant->getAPInt();
@@ -2423,12 +2417,9 @@ bool DependenceAnalysis::gcdMIVtest(const SCEV *Src,
       if (CurLoop == AddRec->getLoop())
         DstCoeff = Coeff;
       else {
-        if (const SCEVMulExpr *Product = dyn_cast<SCEVMulExpr>(Coeff))
-          // If the coefficient is the product of a constant and other stuff,
-          // we can use the constant in the GCD computation.
-          Constant = getConstantPart(Product);
-        else
-          Constant = cast<SCEVConstant>(Coeff);
+        // If the coefficient is the product of a constant and other stuff,
+        // we can use the constant in the GCD computation.
+        Constant = getConstantPart(Coeff);
         if (!Constant)
           return false;
         APInt ConstCoeff = Constant->getAPInt();
@@ -2437,19 +2428,13 @@ bool DependenceAnalysis::gcdMIVtest(const SCEV *Src,
       Inner = AddRec->getStart();
     }
     Delta = SE->getMinusSCEV(SrcCoeff, DstCoeff);
-    if (const SCEVMulExpr *Product = dyn_cast<SCEVMulExpr>(Delta))
-      // If the coefficient is the product of a constant and other stuff,
-      // we can use the constant in the GCD computation.
-      Constant = getConstantPart(Product);
-    else if (isa<SCEVConstant>(Delta))
-      Constant = cast<SCEVConstant>(Delta);
-    else {
+    // If the coefficient is the product of a constant and other stuff,
+    // we can use the constant in the GCD computation.
+    Constant = getConstantPart(Delta);
+    if (!Constant)
       // The difference of the two coefficients might not be a product
       // or constant, in which case we give up on this direction.
       continue;
-    }
-    if (!Constant)
-      continue;
     APInt ConstCoeff = Constant->getAPInt();
     RunningGCD = APIntOps::GreatestCommonDivisor(RunningGCD, ConstCoeff.abs());
     DEBUG(dbgs() << "\tRunningGCD = " << RunningGCD << "\n");