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[CIR] Backport LValueBitcast for ComplexType #1827

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Merged
merged 1 commit into from
Aug 15, 2025
Merged

[CIR] Backport LValueBitcast for ComplexType #1827

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13 changes: 11 additions & 2 deletions clang/lib/CIR/CodeGen/CIRGenExpr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1056,7 +1056,8 @@ LValue CIRGenFunction::emitDeclRefLValue(const DeclRefExpr *E) {
cir::GlobalOp var = CGM.getOrCreateStaticVarDecl(
*VD, CGM.getCIRLinkageVarDefinition(VD, /*IsConstant=*/false));
auto getGlobalOp = builder.createGetGlobal(var);
auto actualElemTy = llvm::cast<cir::PointerType>(getGlobalOp.getType()).getPointee();
auto actualElemTy =
llvm::cast<cir::PointerType>(getGlobalOp.getType()).getPointee();
addr = Address(getGlobalOp, actualElemTy, getContext().getDeclAlign(VD));
} else {
llvm_unreachable("DeclRefExpr for decl not entered in LocalDeclMap?");
Expand Down Expand Up @@ -2017,7 +2018,15 @@ LValue CIRGenFunction::emitCastLValue(const CastExpr *E) {
assert(0 && "NYI");
}
case CK_LValueBitCast: {
assert(0 && "NYI");
// This must be a reinterpret_cast (or c-style equivalent).
const auto *ce = cast<ExplicitCastExpr>(E);

CGM.emitExplicitCastExprType(ce, this);
LValue LV = emitLValue(E->getSubExpr());
Address V = LV.getAddress().withElementType(
builder, convertTypeForMem(ce->getTypeAsWritten()->getPointeeType()));

return makeAddrLValue(V, E->getType(), LV.getBaseInfo(), LV.getTBAAInfo());
}
case CK_AddressSpaceConversion: {
LValue LV = emitLValue(E->getSubExpr());
Expand Down
9 changes: 7 additions & 2 deletions clang/lib/CIR/CodeGen/CIRGenExprComplex.cpp
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Expand Up @@ -428,8 +428,13 @@ mlir::Value ComplexExprEmitter::emitCast(CastKind CK, Expr *Op,
case CK_UserDefinedConversion:
llvm_unreachable("NYI");

case CK_LValueBitCast:
llvm_unreachable("NYI");
case CK_LValueBitCast: {
LValue origLV = CGF.emitLValue(Op);
Address addr =
origLV.getAddress().withElementType(Builder, CGF.convertType(DestTy));
LValue destLV = CGF.makeAddrLValue(addr, DestTy);
return emitLoadOfLValue(destLV, Op->getExprLoc());
}

case CK_LValueToRValueBitCast: {
LValue SourceLVal = CGF.emitLValue(Op);
Expand Down
21 changes: 21 additions & 0 deletions clang/test/CIR/CodeGen/complex-cast.cpp
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@@ -0,0 +1,21 @@
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -x c++ -fclangir -emit-cir -mmlir --mlir-print-ir-before=cir-canonicalize -o %t.cir %s 2>&1 | FileCheck --check-prefix=CIR-BEFORE %s
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -x c++ -fclangir -emit-cir -mmlir --mlir-print-ir-after=cir-canonicalize -o %t.cir %s 2>&1 | FileCheck --check-prefix=CIR-AFTER %s
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm -o %t.ll %s
// RUN: FileCheck --input-file=%t.ll --check-prefixes=LLVM %s

struct CX {
double real;
double imag;
};

void complex_lvalue_bitcast() {
struct CX a;
(double _Complex &)a = {};
}

// CIR-BEFORE: %{{.*}} = cir.cast(bitcast, %{{.*}} : !cir.ptr<!rec_CX>), !cir.ptr<!cir.complex<!cir.double>>

// CIR-AFTER: %{{.*}} = cir.cast(bitcast, %{{.*}} : !cir.ptr<!rec_CX>), !cir.ptr<!cir.complex<!cir.double>>

// LLVM: %[[A_ADDR:.*]] = alloca %struct.CX, i64 1, align 8
// LLVM: store { double, double } zeroinitializer, ptr %[[A_ADDR]], align 8
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