[InstCombine] [NFC] separate a function foldICmpBinOpWithConstant

[Chenbing.Zheng]

Summary

There is a long function foldICmpInstWithConstant,
we can separate a function foldICmpBinOpWithConstant from it.

[spatel]

LGTM

[RKSimon]

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

3337

@Chenbing.Zheng Is a return nullptr missing from the end of the function? Or just:

// TODO: These folds could be refactored to be part of the above calls.
return foldICmpBinOpEqualityWithConstant(Cmp, BO, C));

[spatel]

@RKSimon spotted a bug (and that should have generated a compile warning too).

[Chenbing.Zheng]

bug fix

[Chenbing.Zheng]

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

3337

yer, thanks for your advice. I have fixed it.

[spatel]

LGTM

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

 /// Try to fold integer comparisons with a constant operand: icmp Pred X, C
 /// where X is some kind of instruction.
 Instruction *InstCombinerImpl::foldICmpInstWithConstant(ICmpInst &Cmp) {
   const APInt *C;
   if (!match(Cmp.getOperand(1), m_APInt(C)))
     return nullptr;
 
   if (auto *BO = dyn_cast<BinaryOperator>(Cmp.getOperand(0))) {
-    switch (BO->getOpcode()) {
-    case Instruction::Xor:
-      if (Instruction *I = foldICmpXorConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::And:
-      if (Instruction *I = foldICmpAndConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::Or:
-      if (Instruction *I = foldICmpOrConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::Mul:
-      if (Instruction *I = foldICmpMulConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::Shl:
-      if (Instruction *I = foldICmpShlConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::LShr:
-    case Instruction::AShr:
-      if (Instruction *I = foldICmpShrConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::SRem:
-      if (Instruction *I = foldICmpSRemConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::UDiv:
-      if (Instruction *I = foldICmpUDivConstant(Cmp, BO, *C))
-        return I;
-      LLVM_FALLTHROUGH;
-    case Instruction::SDiv:
-      if (Instruction *I = foldICmpDivConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::Sub:
-      if (Instruction *I = foldICmpSubConstant(Cmp, BO, *C))
-        return I;
-      break;
-    case Instruction::Add:
-      if (Instruction *I = foldICmpAddConstant(Cmp, BO, *C))
-        return I;
-      break;
-    default:
-      break;
-    }
-    // TODO: These folds could be refactored to be part of the above calls.
-    if (Instruction *I = foldICmpBinOpEqualityWithConstant(Cmp, BO, *C))
+    if (Instruction *I = foldICmpBinOpWithConstant(Cmp, BO, *C))
       return I;
   }
 
   // Match against CmpInst LHS being instructions other than binary operators.
 
   if (auto *SI = dyn_cast<SelectInst>(Cmp.getOperand(0))) {
     // For now, we only support constant integers while folding the
     // ICMP(SELECT)) pattern. We can extend this to support vector of integers
case Intrinsic::fshr:
     return new ICmpInst(Pred, IIOp0->getOperand(0), IIOp1->getOperand(0));
   default:
     break;
   }
 
   return nullptr;
 }
 
+/// Fold an icmp with BinaryOp and constant operand: icmp Pred BO, C.
+Instruction *InstCombinerImpl::foldICmpBinOpWithConstant(ICmpInst &Cmp,
+                                                         BinaryOperator *BO,
+                                                         const APInt &C) {
+  switch (BO->getOpcode()) {
+  case Instruction::Xor:
+    if (Instruction *I = foldICmpXorConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::And:
+    if (Instruction *I = foldICmpAndConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::Or:
+    if (Instruction *I = foldICmpOrConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::Mul:
+    if (Instruction *I = foldICmpMulConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::Shl:
+    if (Instruction *I = foldICmpShlConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::LShr:
+  case Instruction::AShr:
+    if (Instruction *I = foldICmpShrConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::SRem:
+    if (Instruction *I = foldICmpSRemConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::UDiv:
+    if (Instruction *I = foldICmpUDivConstant(Cmp, BO, C))
+      return I;
+    LLVM_FALLTHROUGH;
+  case Instruction::SDiv:
+    if (Instruction *I = foldICmpDivConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::Sub:
+    if (Instruction *I = foldICmpSubConstant(Cmp, BO, C))
+      return I;
+    break;
+  case Instruction::Add:
+    if (Instruction *I = foldICmpAddConstant(Cmp, BO, C))
+      return I;
+    break;
+  default:
+    break;
+  }
+
+  // TODO: These folds could be refactored to be part of the above calls.
+  return foldICmpBinOpEqualityWithConstant(Cmp, BO, C);
+}
+
 /// Fold an icmp with LLVM intrinsic and constant operand: icmp Pred II, C.
 Instruction *InstCombinerImpl::foldICmpIntrinsicWithConstant(ICmpInst &Cmp,
                                                              IntrinsicInst *II,
                                                              const APInt &C) {
   if (Cmp.isEquality())
     return foldICmpEqIntrinsicWithConstant(Cmp, II, C);
 
   Type *Ty = II->getType();

llvm/lib/Transforms/InstCombine/InstCombineInternal.h

public:
   Instruction *foldICmpBinOp(ICmpInst &Cmp, const SimplifyQuery &SQ);
   Instruction *foldICmpEquality(ICmpInst &Cmp);
   Instruction *foldIRemByPowerOfTwoToBitTest(ICmpInst &I);
   Instruction *foldSignBitTest(ICmpInst &I);
   Instruction *foldICmpWithZero(ICmpInst &Cmp);
 
   Value *foldMultiplicationOverflowCheck(ICmpInst &Cmp);
 
+  Instruction *foldICmpBinOpWithConstant(ICmpInst &Cmp, BinaryOperator *BO,
+                                         const APInt &C);
   Instruction *foldICmpSelectConstant(ICmpInst &Cmp, SelectInst *Select,
                                       ConstantInt *C);
   Instruction *foldICmpTruncConstant(ICmpInst &Cmp, TruncInst *Trunc,
                                      const APInt &C);
   Instruction *foldICmpAndConstant(ICmpInst &Cmp, BinaryOperator *And,
                                    const APInt &C);
   Instruction *foldICmpXorConstant(ICmpInst &Cmp, BinaryOperator *Xor,
                                    const APInt &C);