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[CIR][LLVMLowering] Upstream Bitcast lowering #140774

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Merged
merged 1 commit into from
May 21, 2025
Merged

[CIR][LLVMLowering] Upstream Bitcast lowering #140774

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12 changes: 10 additions & 2 deletions clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -530,10 +530,18 @@ mlir::LogicalResult CIRToLLVMCastOpLowering::matchAndRewrite(
llvmSrcVal);
return mlir::success();
}
case cir::CastKind::bitcast:
case cir::CastKind::bitcast: {
mlir::Type dstTy = castOp.getType();
mlir::Type llvmDstTy = getTypeConverter()->convertType(dstTy);

assert(!MissingFeatures::cxxABI());
assert(!MissingFeatures::dataMemberType());
break;

mlir::Value llvmSrcVal = adaptor.getOperands().front();
rewriter.replaceOpWithNewOp<mlir::LLVM::BitcastOp>(castOp, llvmDstTy,
llvmSrcVal);
return mlir::success();
}
case cir::CastKind::ptr_to_bool: {
mlir::Value llvmSrcVal = adaptor.getOperands().front();
mlir::Value zeroPtr = rewriter.create<mlir::LLVM::ZeroOp>(
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17 changes: 15 additions & 2 deletions clang/test/CIR/CodeGen/cast.cpp
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Expand Up @@ -25,7 +25,6 @@ unsigned char cxxstaticcast_0(unsigned int x) {
// LLVM: %[[R:[0-9]+]] = load i8, ptr %[[RV]], align 1
// LLVM: ret i8 %[[R]]


int cStyleCasts_0(unsigned x1, int x2, float x3, short x4, double x5) {
// CIR: cir.func @_Z13cStyleCasts_0jifsd
// LLVM: define i32 @_Z13cStyleCasts_0jifsd
Expand Down Expand Up @@ -103,10 +102,24 @@ void should_not_cast() {

bool x2;
bool ib = (bool)x2; // identity

(void) ib; // void cast
}

// CIR: cir.func @_Z15should_not_castv
// CIR-NOT: cir.cast
// CIR: cir.return

typedef int vi4 __attribute__((vector_size(16)));
typedef double vd2 __attribute__((vector_size(16)));

void bitcast() {
vd2 a = {};
vi4 b = (vi4)a;
}

// CIR: %[[D_VEC:.*]] = cir.load {{.*}} : !cir.ptr<!cir.vector<2 x !cir.double>>, !cir.vector<2 x !cir.double>
// CIR: %[[I_VEC:.*]] = cir.cast(bitcast, %[[D_VEC]] : !cir.vector<2 x !cir.double>), !cir.vector<4 x !s32i>

// LLVM: %[[D_VEC:.*]] = load <2 x double>, ptr {{.*}}, align 16
// LLVM: %[[I_VEC:.*]] = bitcast <2 x double> %[[D_VEC]] to <4 x i32>