[llvm] 8fa4807 - [ExpandIRInsts] Simplify constant construction (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2026-01-29T15:15:29+01:00
New Revision: 8fa48070ec4055191239ed48c29e039c2358d48a

URL: https://github.com/llvm/llvm-project/commit/8fa48070ec4055191239ed48c29e039c2358d48a
DIFF: https://github.com/llvm/llvm-project/commit/8fa48070ec4055191239ed48c29e039c2358d48a.diff

LOG: [ExpandIRInsts] Simplify constant construction (NFC)

Don't go through IRBuilder for constants we can create with
APInt APIs.

Added: 
    

Modified: 
    llvm/lib/CodeGen/ExpandIRInsts.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/ExpandIRInsts.cpp b/llvm/lib/CodeGen/ExpandIRInsts.cpp
index 311e04d726527..b1379d01feaea 100644
--- a/llvm/lib/CodeGen/ExpandIRInsts.cpp
+++ b/llvm/lib/CodeGen/ExpandIRInsts.cpp
@@ -528,14 +528,10 @@ static void expandFPToI(Instruction *FPToI) {
       PowerOf2Ceil(FloatVal->getType()->getScalarSizeInBits());
   unsigned ExponentWidth = FloatWidth - FPMantissaWidth - 1;
   unsigned ExponentBias = (1 << (ExponentWidth - 1)) - 1;
-  Value *ImplicitBit = Builder.CreateShl(
-      Builder.getIntN(BitWidth, 1), Builder.getIntN(BitWidth, FPMantissaWidth));
+  Value *ImplicitBit =
+      ConstantInt::get(IntTy, APInt::getOneBitSet(BitWidth, FPMantissaWidth));
   Value *SignificandMask =
-      Builder.CreateSub(ImplicitBit, Builder.getIntN(BitWidth, 1));
-  Value *NegOne = ConstantInt::getAllOnesValue(IntTy);
-  Value *NegInf =
-      Builder.CreateShl(ConstantInt::getSigned(IntTy, 1),
-                        ConstantInt::getSigned(IntTy, BitWidth - 1));
+      ConstantInt::get(IntTy, APInt::getLowBitsSet(BitWidth, FPMantissaWidth));
 
   BasicBlock *Entry = Builder.GetInsertBlock();
   Function *F = Entry->getParent();
@@ -591,7 +587,8 @@ static void expandFPToI(Instruction *FPToI) {
 
   // if.then5:
   Builder.SetInsertPoint(IfThen5);
-  Value *PosInf = Builder.CreateXor(NegOne, NegInf);
+  Value *PosInf = ConstantInt::get(IntTy, APInt::getSignedMaxValue(BitWidth));
+  Value *NegInf = ConstantInt::get(IntTy, APInt::getSignedMinValue(BitWidth));
   Value *Cond8 = Builder.CreateSelect(PosOrNeg, PosInf, NegInf);
   Builder.CreateBr(End);