diff options
Diffstat (limited to 'lib/CodeGen/CGExpr.cpp')
| -rw-r--r-- | lib/CodeGen/CGExpr.cpp | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp index 95733abbab..9328a53567 100644 --- a/lib/CodeGen/CGExpr.cpp +++ b/lib/CodeGen/CGExpr.cpp @@ -392,7 +392,8 @@ void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst, } void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst, - QualType Ty) { + QualType Ty, + llvm::Value **Result) { unsigned StartBit = Dst.getBitfieldStartBit(); unsigned BitfieldSize = Dst.getBitfieldSize(); llvm::Value *Ptr = Dst.getBitfieldAddr(); @@ -403,12 +404,31 @@ void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst, // Get the new value, cast to the appropriate type and masked to // exactly the size of the bit-field. - llvm::Value *NewVal = Src.getScalarVal(); - NewVal = Builder.CreateIntCast(NewVal, EltTy, false, "tmp"); + llvm::Value *SrcVal = Src.getScalarVal(); + llvm::Value *NewVal = Builder.CreateIntCast(SrcVal, EltTy, false, "tmp"); llvm::Constant *Mask = llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize)); NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value"); + // Return the new value of the bit-field, if requested. + if (Result) { + // Cast back to the proper type for result. + const llvm::Type *SrcTy = SrcVal->getType(); + llvm::Value *SrcTrunc = Builder.CreateIntCast(NewVal, SrcTy, false, + "bf.reload.val"); + + // Sign extend if necessary. + if (Dst.isBitfieldSigned()) { + unsigned SrcTySize = CGM.getTargetData().getTypeSizeInBits(SrcTy); + llvm::Value *ExtraBits = llvm::ConstantInt::get(SrcTy, + SrcTySize - BitfieldSize); + SrcTrunc = Builder.CreateAShr(Builder.CreateShl(SrcTrunc, ExtraBits), + ExtraBits, "bf.reload.sext"); + } + + *Result = SrcTrunc; + } + // In some cases the bitfield may straddle two memory locations. // Emit the low part first and check to see if the high needs to be // done. |