[Mlir-commits] [mlir] [MLIR][NVVM] Add prefetch Ops (PR #141737)
Srinivasa Ravi
llvmlistbot at llvm.org
Sun Jun 1 23:05:47 PDT 2025
https://github.com/Wolfram70 updated https://github.com/llvm/llvm-project/pull/141737
>From 94e46fedfe3d9a16722b3ebde56c07e0f29d9c2d Mon Sep 17 00:00:00 2001
From: Srinivasa Ravi <srinivasar at nvidia.com>
Date: Tue, 27 May 2025 15:35:05 +0530
Subject: [PATCH] [MLIR][NVVM] Add prefetch Ops
This change adds `prefetch.L1`, `prefetch.L2`, and `prefetch.L1.uniform`
Ops to the NVVM dialect for the `prefetch` and `prefetchu` group of
instructions.
PTX Spec Reference: https://docs.nvidia.com/cuda/parallel-thread-execution/#data-movement-and-conversion-instructions-prefetch-prefetchu
---
.../include/mlir/Dialect/LLVMIR/NVVMDialect.h | 4 +
mlir/include/mlir/Dialect/LLVMIR/NVVMOps.td | 86 +++++++++++++++++++
mlir/lib/Dialect/LLVMIR/IR/NVVMDialect.cpp | 54 ++++++++++++
mlir/test/Dialect/LLVMIR/nvvm.mlir | 23 +++++
mlir/test/Target/LLVMIR/nvvm/prefetch.mlir | 47 ++++++++++
mlir/test/Target/LLVMIR/nvvmir-invalid.mlir | 40 +++++++++
6 files changed, 254 insertions(+)
create mode 100644 mlir/test/Target/LLVMIR/nvvm/prefetch.mlir
diff --git a/mlir/include/mlir/Dialect/LLVMIR/NVVMDialect.h b/mlir/include/mlir/Dialect/LLVMIR/NVVMDialect.h
index fc38a3fb2d387..6137bb087c576 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/NVVMDialect.h
+++ b/mlir/include/mlir/Dialect/LLVMIR/NVVMDialect.h
@@ -36,12 +36,16 @@ constexpr int kSharedMemoryAlignmentBit = 128;
/// NVVM memory space identifiers.
enum NVVMMemorySpace {
+ /// Generic memory space identifier.
+ kGenericMemorySpace = 0,
/// Global memory space identifier.
kGlobalMemorySpace = 1,
/// Shared memory space identifier.
kSharedMemorySpace = 3,
/// Constant memory space identifier.
kConstantMemorySpace = 4,
+ /// Local memory space identifier.
+ kLocalMemorySpace = 5,
/// Tensor memory space identifier.
/// Tensor memory is available only in arch-accelerated
/// variants from sm100 onwards.
diff --git a/mlir/include/mlir/Dialect/LLVMIR/NVVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/NVVMOps.td
index 2424e3af80d2d..621583a274762 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/NVVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/NVVMOps.td
@@ -25,6 +25,7 @@ include "mlir/Dialect/LLVMIR/LLVMTypes.td"
def LLVM_PointerGeneric : LLVM_PointerInAddressSpace<0>;
def LLVM_PointerGlobal : LLVM_PointerInAddressSpace<1>;
def LLVM_PointerShared : LLVM_PointerInAddressSpace<3>;
+def LLVM_PointerLocal : LLVM_PointerInAddressSpace<5>;
def LLVM_PointerTensor : LLVM_PointerInAddressSpace<6>;
def LLVM_PointerSharedCluster : LLVM_PointerInAddressSpace<7>;
@@ -118,6 +119,25 @@ class NVVM_Attr<string attrName, string attrMnemonic, list<Trait> traits = []>
let mnemonic = attrMnemonic;
}
+// Cache Eviction Priority enum definitions
+def EvictNormal : I32EnumCase<"EvictNormal", 0, "evict_normal">;
+def EvictFirst : I32EnumCase<"EvictFirst", 1, "evict_first">;
+def EvictLast : I32EnumCase<"EvictLast", 2, "evict_last">;
+def EvictUnchanged : I32EnumCase<"EvictUnchanged", 3, "evict_unchanged">;
+def NoAllocate : I32EnumCase<"NoAllocate", 4, "no_allocate">;
+
+def CacheEvictionPriority : I32Enum<"CacheEvictionPriority",
+ "NVVM Cache Eviction Priority",
+ [EvictNormal, EvictFirst, EvictLast,
+ EvictUnchanged, NoAllocate]> {
+ let cppNamespace = "::mlir::NVVM";
+}
+
+def CacheEvictionPriorityAttr : EnumAttr<NVVM_Dialect, CacheEvictionPriority,
+ "cache_eviction_priority"> {
+ let assemblyFormat = "$value";
+}
+
//===----------------------------------------------------------------------===//
// NVVM intrinsic operations
//===----------------------------------------------------------------------===//
@@ -2333,6 +2353,72 @@ def NVVM_CpAsyncBulkTensorSharedCTAToGlobalOp :
let hasVerifier = 1;
}
+//===----------------------------------------------------------------------===//
+// NVVM Prefetch Ops
+//===----------------------------------------------------------------------===//
+
+def NVVM_PrefetchL1Op : NVVM_Op<"prefetch.L1"> {
+ let summary = "Brings the cache line containing the specified address into L1 cache";
+ let description = [{
+ Operand `addr` can be a global, local or generic address pointer.
+ No operation is performed if `addr` maps to a `shared` memory location.
+
+ [For more information, see PTX ISA](https://docs.nvidia.com/cuda/parallel-thread-execution/#data-movement-and-conversion-instructions-prefetch-prefetchu)
+ }];
+ let arguments = (ins AnyTypeOf<[LLVM_PointerGlobal,
+ LLVM_PointerLocal,
+ LLVM_PointerGeneric]>:$addr);
+ let assemblyFormat = "$addr attr-dict `:` type($addr)";
+
+ let extraClassDeclaration = [{
+ static llvm::Intrinsic::ID getIntrinsicID(Operation &op);
+ }];
+ let llvmBuilder = [{
+ auto intId = NVVM::PrefetchL1Op::getIntrinsicID(*op);
+ createIntrinsicCall(builder, intId, $addr);
+ }];
+}
+
+def NVVM_PrefetchL1UniformOp : NVVM_Op<"prefetch.L1.uniform"> {
+ let summary = "Brings the cache line containing the specified address into L1 uniform cache";
+ let description = [{
+ Operand `addr` must be a generic address pointer and no operation is
+ performed if `addr` maps to a `const`, `local`, or `shared` memory location.
+
+ [For more information, see PTX ISA](https://docs.nvidia.com/cuda/parallel-thread-execution/#data-movement-and-conversion-instructions-prefetch-prefetchu)
+ }];
+ let arguments = (ins LLVM_PointerGeneric:$addr);
+ let assemblyFormat = "$addr attr-dict `:` type($addr)";
+
+ let llvmBuilder = [{
+ createIntrinsicCall(builder, llvm::Intrinsic::nvvm_prefetchu_L1, $addr);
+ }];
+}
+
+def NVVM_PrefetchL2Op : NVVM_Op<"prefetch.L2"> {
+ let summary = "Brings the cache line containing the specified address into L2 cache";
+ let description = [{
+ Operand `addr` can be a global, local or generic address pointer.
+ No operation is performed if `addr` maps to a `shared` memory location.
+
+ [For more information, see PTX ISA](https://docs.nvidia.com/cuda/parallel-thread-execution/#data-movement-and-conversion-instructions-prefetch-prefetchu)
+ }];
+ let arguments = (ins AnyTypeOf<[LLVM_PointerGlobal,
+ LLVM_PointerLocal,
+ LLVM_PointerGeneric]>:$addr,
+ OptionalAttr<CacheEvictionPriorityAttr>:$evictPriority);
+ let assemblyFormat = "$addr (`,` `evict_priority` `=` $evictPriority^)? attr-dict `:` type($addr)";
+ let hasVerifier = 1;
+
+ let extraClassDeclaration = [{
+ static llvm::Intrinsic::ID getIntrinsicID(Operation &op);
+ }];
+ let llvmBuilder = [{
+ auto intId = NVVM::PrefetchL2Op::getIntrinsicID(*op);
+ createIntrinsicCall(builder, intId, $addr);
+ }];
+}
+
def NVVM_PrefetchTensorMapOp : NVVM_Op<"prefetch.tensormap",
[DeclareOpInterfaceMethods<BasicPtxBuilderOpInterface>]>,
Arguments<(ins LLVM_AnyPointer:$tmaDescriptor, PtxPredicate:$predicate)> {
diff --git a/mlir/lib/Dialect/LLVMIR/IR/NVVMDialect.cpp b/mlir/lib/Dialect/LLVMIR/IR/NVVMDialect.cpp
index 648b6b087e592..731fbb07b1337 100644
--- a/mlir/lib/Dialect/LLVMIR/IR/NVVMDialect.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/NVVMDialect.cpp
@@ -1205,6 +1205,20 @@ LogicalResult NVVM::VoteSyncOp::verify() {
return success();
}
+LogicalResult NVVM::PrefetchL2Op::verify() {
+ auto evictPriority = getEvictPriority();
+ if (evictPriority &&
+ (llvm::cast<LLVM::LLVMPointerType>(getAddr().getType())
+ .getAddressSpace() != NVVM::NVVMMemorySpace::kGlobalMemorySpace))
+ return emitOpError(
+ "prefetch with cache eviction priority requires a global pointer");
+ if (evictPriority &&
+ *evictPriority != NVVM::CacheEvictionPriority::EvictNormal &&
+ *evictPriority != NVVM::CacheEvictionPriority::EvictLast)
+ return emitOpError("invalid cache eviction priority");
+ return success();
+}
+
/// Packs the given `field` into the `result`.
/// The `result` is 64-bits and each `field` can be 32-bits or narrower.
static llvm::Value *
@@ -1712,6 +1726,46 @@ NVVM::IDArgPair DotAccumulate4WayOp::getIntrinsicIDAndArgs(
return {ids[type], args};
}
+llvm::Intrinsic::ID PrefetchL1Op::getIntrinsicID(Operation &op) {
+ auto curOp = llvm::cast<NVVM::PrefetchL1Op>(op);
+ switch (llvm::cast<LLVM::LLVMPointerType>(curOp.getAddr().getType())
+ .getAddressSpace()) {
+ case NVVM::NVVMMemorySpace::kGenericMemorySpace:
+ return llvm::Intrinsic::nvvm_prefetch_L1;
+ case NVVM::NVVMMemorySpace::kGlobalMemorySpace:
+ return llvm::Intrinsic::nvvm_prefetch_global_L1;
+ case NVVM::NVVMMemorySpace::kLocalMemorySpace:
+ return llvm::Intrinsic::nvvm_prefetch_local_L1;
+ default:
+ llvm_unreachable("Invalid pointer address space");
+ }
+}
+
+llvm::Intrinsic::ID PrefetchL2Op::getIntrinsicID(Operation &op) {
+ auto curOp = llvm::cast<NVVM::PrefetchL2Op>(op);
+ auto evictPriority = curOp.getEvictPriority();
+
+ switch (llvm::cast<LLVM::LLVMPointerType>(curOp.getAddr().getType())
+ .getAddressSpace()) {
+ case NVVM::NVVMMemorySpace::kGenericMemorySpace:
+ return llvm::Intrinsic::nvvm_prefetch_L2;
+ case NVVM::NVVMMemorySpace::kGlobalMemorySpace:
+ if (evictPriority) {
+ if (*evictPriority == NVVM::CacheEvictionPriority::EvictLast)
+ return llvm::Intrinsic::nvvm_prefetch_global_L2_evict_last;
+ else if (*evictPriority == NVVM::CacheEvictionPriority::EvictNormal)
+ return llvm::Intrinsic::nvvm_prefetch_global_L2_evict_normal;
+ else
+ llvm_unreachable("Invalid cache eviction priority");
+ }
+ return llvm::Intrinsic::nvvm_prefetch_global_L2;
+ case NVVM::NVVMMemorySpace::kLocalMemorySpace:
+ return llvm::Intrinsic::nvvm_prefetch_local_L2;
+ default:
+ llvm_unreachable("Invalid pointer address space");
+ }
+}
+
//===----------------------------------------------------------------------===//
// NVVMDialect initialization, type parsing, and registration.
//===----------------------------------------------------------------------===//
diff --git a/mlir/test/Dialect/LLVMIR/nvvm.mlir b/mlir/test/Dialect/LLVMIR/nvvm.mlir
index 77b302155cb12..02ba31973be43 100644
--- a/mlir/test/Dialect/LLVMIR/nvvm.mlir
+++ b/mlir/test/Dialect/LLVMIR/nvvm.mlir
@@ -587,6 +587,29 @@ func.func @dot_accumulate_4way(%a_vec: vector<4xi8>, %b_vec: vector<4xi8>, %c: i
return
}
+// CHECK-LABEL: @prefetch
+func.func @prefetch(%gen_ptr: !llvm.ptr, %local_ptr: !llvm.ptr<5>, %global_ptr: !llvm.ptr<1>) {
+ // CHECK: nvvm.prefetch.L1 %{{.*}}
+ nvvm.prefetch.L1 %gen_ptr : !llvm.ptr<0>
+ // CHECK: nvvm.prefetch.L1 %{{.*}}
+ nvvm.prefetch.L1 %local_ptr : !llvm.ptr<5>
+ // CHECK: nvvm.prefetch.L1 %{{.*}}
+ nvvm.prefetch.L1 %global_ptr : !llvm.ptr<1>
+ // CHECK: nvvm.prefetch.L2 %{{.*}}
+ nvvm.prefetch.L2 %gen_ptr : !llvm.ptr<0>
+ // CHECK: nvvm.prefetch.L2 %{{.*}}
+ nvvm.prefetch.L2 %local_ptr : !llvm.ptr<5>
+ // CHECK: nvvm.prefetch.L2 %{{.*}}
+ nvvm.prefetch.L2 %global_ptr : !llvm.ptr<1>
+ // CHECK: nvvm.prefetch.L2 %{{.*}}
+ nvvm.prefetch.L2 %global_ptr, evict_priority = evict_last : !llvm.ptr<1>
+ // CHECK: nvvm.prefetch.L2 %{{.*}}
+ nvvm.prefetch.L2 %global_ptr, evict_priority = evict_normal : !llvm.ptr<1>
+ // CHECK: nvvm.prefetch.L1.uniform %{{.*}}
+ nvvm.prefetch.L1.uniform %gen_ptr : !llvm.ptr
+ return
+}
+
// -----
// Just check these don't emit errors.
diff --git a/mlir/test/Target/LLVMIR/nvvm/prefetch.mlir b/mlir/test/Target/LLVMIR/nvvm/prefetch.mlir
new file mode 100644
index 0000000000000..b6532ff0fbf0d
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/nvvm/prefetch.mlir
@@ -0,0 +1,47 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+llvm.func @prefetch_L1(%gen_ptr: !llvm.ptr, %local_ptr: !llvm.ptr<5>, %global_ptr: !llvm.ptr<1>) {
+ // CHECK-LABEL: define void @prefetch_L1(ptr %0, ptr addrspace(5) %1, ptr addrspace(1) %2) {
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.L1(ptr %0)
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.local.L1(ptr addrspace(5) %1)
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.global.L1(ptr addrspace(1) %2)
+ // CHECK-NEXT: ret void
+ // CHECK-NEXT: }
+ nvvm.prefetch.L1 %gen_ptr : !llvm.ptr<0>
+ nvvm.prefetch.L1 %local_ptr : !llvm.ptr<5>
+ nvvm.prefetch.L1 %global_ptr : !llvm.ptr<1>
+ llvm.return
+}
+
+llvm.func @prefetch_L2(%gen_ptr: !llvm.ptr, %local_ptr: !llvm.ptr<5>, %global_ptr: !llvm.ptr<1>) {
+ // CHECK-LABEL: define void @prefetch_L2(ptr %0, ptr addrspace(5) %1, ptr addrspace(1) %2) {
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.L2(ptr %0)
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.local.L2(ptr addrspace(5) %1)
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.global.L2(ptr addrspace(1) %2)
+ // CHECK-NEXT: ret void
+ // CHECK-NEXT: }
+ nvvm.prefetch.L2 %gen_ptr : !llvm.ptr<0>
+ nvvm.prefetch.L2 %local_ptr : !llvm.ptr<5>
+ nvvm.prefetch.L2 %global_ptr : !llvm.ptr<1>
+ llvm.return
+}
+
+llvm.func @prefetch_L2_eviction_priority(%global_ptr: !llvm.ptr<1>) {
+ // CHECK-LABEL: define void @prefetch_L2_eviction_priority(ptr addrspace(1) %0) {
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.global.L2.evict.last(ptr addrspace(1) %0)
+ // CHECK-NEXT: call void @llvm.nvvm.prefetch.global.L2.evict.normal(ptr addrspace(1) %0)
+ // CHECK-NEXT: ret void
+ // CHECK-NEXT: }
+ nvvm.prefetch.L2 %global_ptr, evict_priority = evict_last : !llvm.ptr<1>
+ nvvm.prefetch.L2 %global_ptr, evict_priority = evict_normal : !llvm.ptr<1>
+ llvm.return
+}
+
+llvm.func @prefetch_L1_uniform(%gen_ptr: !llvm.ptr) {
+ // CHECK-LABEL: define void @prefetch_L1_uniform(ptr %0) {
+ // CHECK-NEXT: call void @llvm.nvvm.prefetchu.L1(ptr %0)
+ // CHECK-NEXT: ret void
+ // CHECK-NEXT: }
+ nvvm.prefetch.L1.uniform %gen_ptr : !llvm.ptr
+ llvm.return
+}
\ No newline at end of file
diff --git a/mlir/test/Target/LLVMIR/nvvmir-invalid.mlir b/mlir/test/Target/LLVMIR/nvvmir-invalid.mlir
index 3d63434f310bd..08f6d7aea2231 100644
--- a/mlir/test/Target/LLVMIR/nvvmir-invalid.mlir
+++ b/mlir/test/Target/LLVMIR/nvvmir-invalid.mlir
@@ -248,3 +248,43 @@ llvm.func @nvvm_cvt_bf16x2_to_f8x2_invalid_rounding(%src : vector<2xbf16>) {
%res = nvvm.convert.bf16x2.to.f8x2 <ue8m0> %src {rnd = #nvvm.fp_rnd_mode<rn>} : vector<2xbf16> -> i16
llvm.return
}
+
+// -----
+
+llvm.func @nvvm_prefetch_L2_with_evict_last_invalid_addr_space(%local_ptr: !llvm.ptr<5>) {
+ // expected-error @below {{prefetch with cache eviction priority requires a global pointer}}
+ nvvm.prefetch.L2 %local_ptr, evict_priority = evict_last : !llvm.ptr<5>
+ llvm.return
+}
+
+// -----
+
+llvm.func @nvvm_prefetch_L2_with_evict_normal_invalid_addr_space(%local_ptr: !llvm.ptr<5>) {
+ // expected-error @below {{prefetch with cache eviction priority requires a global pointer}}
+ nvvm.prefetch.L2 %local_ptr, evict_priority = evict_normal : !llvm.ptr<5>
+ llvm.return
+}
+
+// -----
+
+llvm.func @nvvm_prefetch_L2_with_invalid_evict_first(%global_ptr: !llvm.ptr<1>) {
+ // expected-error @below {{invalid cache eviction priority}}
+ nvvm.prefetch.L2 %global_ptr, evict_priority = evict_first : !llvm.ptr<1>
+ llvm.return
+}
+
+// -----
+
+llvm.func @nvvm_prefetch_L2_with_invalid_evict_unchanged(%global_ptr: !llvm.ptr<1>) {
+ // expected-error @below {{invalid cache eviction priority}}
+ nvvm.prefetch.L2 %global_ptr, evict_priority = evict_unchanged : !llvm.ptr<1>
+ llvm.return
+}
+
+// -----
+
+llvm.func @nvvm_prefetch_L2_with_invalid_no_allocate(%global_ptr: !llvm.ptr<1>) {
+ // expected-error @below {{invalid cache eviction priority}}
+ nvvm.prefetch.L2 %global_ptr, evict_priority = no_allocate : !llvm.ptr<1>
+ llvm.return
+}
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