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[CIR] Added codegen support for builtin_mempcpy #1844

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Merged
merged 3 commits into from
Aug 22, 2025
Merged

[CIR] Added codegen support for builtin_mempcpy #1844

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b2324bc
[CIR] Added codegen support for builtin_mempcpy
badumbatish Aug 20, 2025
c5f91e2
Resolve PR reviews, add extra checks for future
badumbatish Aug 20, 2025
9ec883b
Stricter SSA check for test, resolve PR comments
badumbatish Aug 21, 2025
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13 changes: 9 additions & 4 deletions clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1687,10 +1687,15 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
builder.createMemCpy(getLoc(E->getSourceRange()), Dest.getPointer(),
Src.getPointer(), SizeVal);
if (BuiltinID == Builtin::BImempcpy ||
BuiltinID == Builtin::BI__builtin_mempcpy)
llvm_unreachable("mempcpy is NYI");
else
return RValue::get(Dest.getPointer());
BuiltinID == Builtin::BI__builtin_mempcpy) {
auto ppTy = builder.getPointerTo(builder.getUInt8PtrTy());
auto castBuf = builder.createBitcast(Dest.getPointer(), ppTy);
auto loc = getLoc(E->getSourceRange());
auto gep = cir::PtrStrideOp::create(builder, loc, ppTy, castBuf, SizeVal);
assert(!cir::MissingFeatures::emitCheckedInBoundsGEP());
return RValue::get(gep);
}
return RValue::get(Dest.getPointer());
}

case Builtin::BI__builtin_memcpy_inline: {
Expand Down
28 changes: 28 additions & 0 deletions clang/test/CIR/CodeGen/builtins-memory.c
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Expand Up @@ -3,6 +3,9 @@
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o - \
// RUN: | opt -S -passes=instcombine,mem2reg,simplifycfg -o %t.ll
// RUN: FileCheck --check-prefix=LLVM --input-file=%t.ll %s
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o - \
// RUN: | opt -S -passes=instcombine,mem2reg,simplifycfg -o %t.ll
// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s

typedef __SIZE_TYPE__ size_t;
void test_memcpy_chk(void *dest, const void *src, size_t n) {
Expand Down Expand Up @@ -230,3 +233,28 @@ void test_memset_inline(void *dst, int val) {
// LLVM: call void @llvm.memset.inline.p0.i64(ptr {{%.*}}, i8 {{%.*}}, i64 4, i1 false)
__builtin_memset_inline(dst, val, 4);
}

void* test_builtin_mempcpy(void *dest, void *src, size_t n) {
// CIR-LABEL: test_builtin_mempcpy
// CIR: [[ALLOCA:%.*]] = cir.alloca !cir.ptr<!void>, !cir.ptr<!cir.ptr<!void>>, ["__retval"]
// CIR: cir.libc.memcpy [[NUM:%.*]] bytes from [[S:.*]] to [[DST:.*]] :
// CIR: [[CAST2:%.*]] = cir.cast(bitcast, [[DST]] : !cir.ptr<!void>), !cir.ptr<!cir.ptr<!u8i>>
// CIR: [[GEP:%.*]] = cir.ptr_stride([[CAST2]] : !cir.ptr<!cir.ptr<!u8i>>, [[NUM]] : !u64i)
// CIR: [[CAST3:%.*]] = cir.cast(bitcast, [[ALLOCA]]
// CIR: cir.store [[GEP]], [[CAST3:%.*]]
// CIR-NEXT: [[LD:%.*]] = cir.load [[ALLOCA]]
// CIR-NEXT: cir.return [[LD]]

// LLVM-LABEL: test_builtin_mempcpy
// LLVM: call void @llvm.memcpy.p0.p0.i64(ptr [[DST:%.*]], ptr {{%.*}}, i64 [[NUM:%.*]], i1 false)
// LLVM-NEXT: [[GEP:%.*]] = getelementptr ptr, ptr [[DST]], i64 [[NUM]]
// LLVM-NEXT: store ptr [[GEP]], ptr [[P:%.*]]
// LLVM-NEXT: [[LD:%.*]] = load ptr, ptr [[P]]
// LLVM-NEXT: ret ptr [[LD]]

// OGCG-LABEL: test_builtin_mempcpy
// OGCG: call void @llvm.memcpy.p0.p0.i64(ptr align 1 [[DST:%.*]], ptr align 1 {{%.*}}, i64 [[NUM:%.*]], i1 false)
// OGCG-NEXT: [[GEP:%.*]] = getelementptr inbounds i8, ptr [[DST]], i64 [[NUM]]
// OGCG-NEXT: ret ptr [[GEP]]
return __builtin_mempcpy(dest, src, n);
}
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