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[CIR][CIRGen][Builtin][X86] Lower mm_prefetch #1675

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Merged
merged 1 commit into from
Jul 3, 2025
Merged

[CIR][CIRGen][Builtin][X86] Lower mm_prefetch #1675

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26 changes: 25 additions & 1 deletion clang/lib/CIR/CodeGen/CIRGenBuiltinX86.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,14 @@ translateX86ToMsvcIntrin(unsigned BuiltinID) {
llvm_unreachable("must return from switch");
}

/// Get integer from a mlir::Value that is an int constant or a constant op.
static int64_t getIntValueFromConstOp(mlir::Value val) {
auto constOp = mlir::cast<cir::ConstantOp>(val.getDefiningOp());
return (mlir::cast<cir::IntAttr>(constOp.getValue()))
.getValue()
.getSExtValue();
}

mlir::Value CIRGenFunction::emitX86BuiltinExpr(unsigned BuiltinID,
const CallExpr *E) {
if (BuiltinID == Builtin::BI__builtin_cpu_is)
Expand Down Expand Up @@ -96,7 +104,23 @@ mlir::Value CIRGenFunction::emitX86BuiltinExpr(unsigned BuiltinID,
default:
return nullptr;
case X86::BI_mm_prefetch: {
llvm_unreachable("_mm_prefetch NYI");
mlir::Value Address = builder.createPtrBitcast(Ops[0], VoidTy);

int64_t Hint = getIntValueFromConstOp(Ops[1]);
mlir::Value RW = builder.create<cir::ConstantOp>(
getLoc(E->getExprLoc()),
cir::IntAttr::get(SInt32Ty, (Hint >> 2) & 0x1));
mlir::Value Locality = builder.create<cir::ConstantOp>(
getLoc(E->getExprLoc()), cir::IntAttr::get(SInt32Ty, Hint & 0x3));
mlir::Value Data = builder.create<cir::ConstantOp>(
getLoc(E->getExprLoc()), cir::IntAttr::get(SInt32Ty, 1));
mlir::Type voidTy = cir::VoidType::get(&getMLIRContext());

return builder
.create<cir::LLVMIntrinsicCallOp>(
getLoc(E->getExprLoc()), builder.getStringAttr("prefetch"), voidTy,
mlir::ValueRange{Address, RW, Locality, Data})
.getResult();
}
case X86::BI_mm_clflush: {
mlir::Type voidTy = cir::VoidType::get(&getMLIRContext());
Expand Down
20 changes: 20 additions & 0 deletions clang/test/CIR/CodeGen/X86/sse-builtins.c
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@@ -0,0 +1,20 @@
// RUN: %clang_cc1 -x c -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fclangir -emit-cir -o %t.cir -Wall -Werror
// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
// RUN: %clang_cc1 -x c -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fclangir -emit-llvm -o %t.ll -Wall -Werror
// RUN: FileCheck --check-prefixes=LLVM --input-file=%t.ll %s

// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fno-signed-char -fclangir -emit-cir -o %t.cir -Wall -Werror
// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
// RUN: %clang_cc1 -x c++ -flax-vector-conversions=none -ffreestanding %s -triple=x86_64-unknown-linux -target-feature +sse -fclangir -emit-llvm -o %t.ll -Wall -Werror
// RUN: FileCheck --check-prefixes=LLVM --input-file=%t.ll %s

#include <immintrin.h>


void test_mm_prefetch(char const* p) {
// CIR-LABEL: test_mm_prefetch
// LLVM-LABEL: test_mm_prefetch
_mm_prefetch(p, 0);
// CIR: cir.prefetch(%{{.*}} : !cir.ptr<!void>) locality(0) read
// LLVM: call void @llvm.prefetch.p0(ptr {{.*}}, i32 0, i32 0, i32 1)
}
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