[InstCombine] add a wrapper for a common pair of transforms; NFCI

Some of the callers are artificially limiting this transform to integer types;
this should make it easier to incrementally remove that restriction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291620 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/InstCombine/InstCombineAddSub.cpp

@@ -1371,15 +1371,9 @@ Instruction *InstCombiner::visitFAdd(BinaryOperator &I) {
           SimplifyFAddInst(LHS, RHS, I.getFastMathFlags(), DL, &TLI, &DT, &AC))
     return replaceInstUsesWith(I, V);
 
-  if (isa<Constant>(RHS)) {
+  if (isa<Constant>(RHS))
-    if (isa<PHINode>(LHS))
+    if (Instruction *FoldedFAdd = foldOpWithConstantIntoOperand(I))
-      if (Instruction *NV = FoldOpIntoPhi(I))
+      return FoldedFAdd;
-        return NV;
-
-    if (SelectInst *SI = dyn_cast<SelectInst>(LHS))
-      if (Instruction *NV = FoldOpIntoSelect(I, SI))
-        return NV;
-  }
 
   // -A + B  -->  B - A
   // -A + -B  -->  -(A + B)

lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -1382,13 +1382,8 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
       }
     }
 
-    // Try to fold constant and into select arguments.
+    if (Instruction *FoldedLogic = foldOpWithConstantIntoOperand(I))
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      return FoldedLogic;
-      if (Instruction *R = FoldOpIntoSelect(I, SI))
-        return R;
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
   }
 
   if (Instruction *DeMorgan = matchDeMorgansLaws(I, Builder))
@@ -2125,14 +2120,8 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
                             Builder->getInt(C1->getValue() & ~RHS->getValue()));
     }
 
-    // Try to fold constant and into select arguments.
+    if (Instruction *FoldedLogic = foldOpWithConstantIntoOperand(I))
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      return FoldedLogic;
-      if (Instruction *R = FoldOpIntoSelect(I, SI))
-        return R;
-
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
   }
 
   // Given an OR instruction, check to see if this is a bswap.
@@ -2594,13 +2583,8 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
       }
     }
 
-    // Try to fold constant and into select arguments.
+    if (Instruction *FoldedLogic = foldOpWithConstantIntoOperand(I))
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      return FoldedLogic;
-      if (Instruction *R = FoldOpIntoSelect(I, SI))
-        return R;
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
   }
 
   BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1);

lib/Transforms/InstCombine/InstCombineInternal.h

@@ -320,7 +320,6 @@ private:
   Value *dyn_castFNegVal(Value *V, bool NoSignedZero = false) const;
   Type *FindElementAtOffset(PointerType *PtrTy, int64_t Offset,
                             SmallVectorImpl<Value *> &NewIndices);
-  Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);
 
   /// Classify whether a cast is worth optimizing.
   ///
@@ -537,13 +536,21 @@ private:
   Value *SimplifyVectorOp(BinaryOperator &Inst);
   Value *SimplifyBSwap(BinaryOperator &Inst);
 
-  // FoldOpIntoPhi - Given a binary operator, cast instruction, or select
+
-  // which has a PHI node as operand #0, see if we can fold the instruction
+  /// Given a binary operator, cast instruction, or select which has a PHI node
-  // into the PHI (which is only possible if all operands to the PHI are
+  /// as operand #0, see if we can fold the instruction into the PHI (which is
-  // constants).
+  /// only possible if all operands to the PHI are constants).
-  //
   Instruction *FoldOpIntoPhi(Instruction &I);
 
+  /// Given an instruction with a select as one operand and a constant as the
+  /// other operand, try to fold the binary operator into the select arguments.
+  /// This also works for Cast instructions, which obviously do not have a
+  /// second operand.
+  Instruction *FoldOpIntoSelect(Instruction &Op, SelectInst *SI);
+
+  /// This is a convenience wrapper function for the above two functions.
+  Instruction *foldOpWithConstantIntoOperand(Instruction &I);
+
   /// \brief Try to rotate an operation below a PHI node, using PHI nodes for
   /// its operands.
   Instruction *FoldPHIArgOpIntoPHI(PHINode &PN);

lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

@@ -267,14 +267,8 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
 
   // Simplify mul instructions with a constant RHS.
   if (isa<Constant>(Op1)) {
-    // Try to fold constant mul into select arguments.
+    if (Instruction *FoldedMul = foldOpWithConstantIntoOperand(I))
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      return FoldedMul;
-      if (Instruction *R = FoldOpIntoSelect(I, SI))
-        return R;
-
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
 
     // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
     {
@@ -626,14 +620,8 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
 
   // Simplify mul instructions with a constant RHS.
   if (isa<Constant>(Op1)) {
-    // Try to fold constant mul into select arguments.
+    if (Instruction *FoldedMul = foldOpWithConstantIntoOperand(I))
-    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      return FoldedMul;
-      if (Instruction *R = FoldOpIntoSelect(I, SI))
-        return R;
-
-    if (isa<PHINode>(Op0))
-      if (Instruction *NV = FoldOpIntoPhi(I))
-        return NV;
 
     // (fmul X, -1.0) --> (fsub -0.0, X)
     if (match(Op1, m_SpecificFP(-1.0))) {
@@ -956,14 +944,9 @@ Instruction *InstCombiner::commonIDivTransforms(BinaryOperator &I) {
         }
       }
 
-      if (*C2 != 0) { // avoid X udiv 0
+      if (*C2 != 0) // avoid X udiv 0
-        if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+        if (Instruction *FoldedDiv = foldOpWithConstantIntoOperand(I))
-          if (Instruction *R = FoldOpIntoSelect(I, SI))
+          return FoldedDiv;
-            return R;
-        if (isa<PHINode>(Op0))
-          if (Instruction *NV = FoldOpIntoPhi(I))
-            return NV;
-      }
     }
   }
 

lib/Transforms/InstCombine/InstCombineShifts.cpp

@@ -530,13 +530,8 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, Constant *Op1,
         return BinaryOperator::CreateMul(BO->getOperand(0),
                                          ConstantExpr::getShl(BOOp, Op1));
 
-  // Try to fold constant and into select arguments.
+  if (Instruction *FoldedShift = foldOpWithConstantIntoOperand(I))
-  if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+    return FoldedShift;
-    if (Instruction *R = FoldOpIntoSelect(I, SI))
-      return R;
-  if (isa<PHINode>(Op0))
-    if (Instruction *NV = FoldOpIntoPhi(I))
-      return NV;
 
   // Fold shift2(trunc(shift1(x,c1)), c2) -> trunc(shift2(shift1(x,c1),c2))
   if (TruncInst *TI = dyn_cast<TruncInst>(Op0)) {

lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -770,10 +770,6 @@ static Value *foldOperationIntoSelectOperand(Instruction &I, Value *SO,
   return RI;
 }
 
-/// Given an instruction with a select as one operand and a constant as the
-/// other operand, try to fold the binary operator into the select arguments.
-/// This also works for Cast instructions, which obviously do not have a second
-/// operand.
 Instruction *InstCombiner::FoldOpIntoSelect(Instruction &Op, SelectInst *SI) {
   // Don't modify shared select instructions.
   if (!SI->hasOneUse())
@@ -824,9 +820,6 @@ Instruction *InstCombiner::FoldOpIntoSelect(Instruction &Op, SelectInst *SI) {
   return SelectInst::Create(SI->getCondition(), NewTV, NewFV, "", nullptr, SI);
 }
 
-/// Given a binary operator, cast instruction, or select which has a PHI node as
-/// operand #0, see if we can fold the instruction into the PHI (which is only
-/// possible if all operands to the PHI are constants).
 Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
   PHINode *PN = cast<PHINode>(I.getOperand(0));
   unsigned NumPHIValues = PN->getNumIncomingValues();
@@ -964,6 +957,19 @@ Instruction *InstCombiner::FoldOpIntoPhi(Instruction &I) {
   return replaceInstUsesWith(I, NewPN);
 }
 
+Instruction *InstCombiner::foldOpWithConstantIntoOperand(Instruction &I) {
+  assert(isa<Constant>(I.getOperand(1)) && "Unexpected operand type");
+
+  if (auto *Sel = dyn_cast<SelectInst>(I.getOperand(0))) {
+    if (Instruction *NewSel = FoldOpIntoSelect(I, Sel))
+      return NewSel;
+  } else if (isa<PHINode>(I.getOperand(0))) {
+    if (Instruction *NewPhi = FoldOpIntoPhi(I))
+      return NewPhi;
+  }
+  return nullptr;
+}
+
 /// Given a pointer type and a constant offset, determine whether or not there
 /// is a sequence of GEP indices into the pointed type that will land us at the
 /// specified offset. If so, fill them into NewIndices and return the resultant