[mlir][LLVM] Add !invariant.group metadata to llvm.load and llvm.store

This patch adds support for the `!invariant.group` metadata to the `llvm.load`
and the `llvm.store` operation.

Author: Lancern

mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td

@@ -229,6 +229,13 @@ class LLVM_MemOpPatterns {
       inst->setMetadata(llvm::LLVMContext::MD_nontemporal, metadata);
     }
   }];
+  code setInvariantGroupCode = [{
+    if ($invariantGroup) {
+      llvm::MDNode *metadata = llvm::MDNode::get(inst->getContext(),
+                                                 std::nullopt);
+      inst->setMetadata(llvm::LLVMContext::MD_invariant_group, metadata);
+    }
+  }];
   code setAccessGroupsMetadataCode = [{
     moduleTranslation.setAccessGroupsMetadata(op, inst);
   }];

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

@@ -351,6 +351,7 @@ def LLVM_LoadOp : LLVM_MemAccessOpBase<"load",
               UnitAttr:$volatile_,
               UnitAttr:$nontemporal,
               UnitAttr:$invariant,
+              UnitAttr:$invariantGroup,
               DefaultValuedAttr<
                 AtomicOrdering, "AtomicOrdering::not_atomic">:$ordering,
               OptionalAttr<StrAttr>:$syncscope);
@@ -386,6 +387,7 @@ def LLVM_LoadOp : LLVM_MemAccessOpBase<"load",
     (`volatile` $volatile_^)? $addr
     (`atomic` (`syncscope` `(` $syncscope^ `)`)? $ordering^)?
     (`invariant` $invariant^)?
+    (`invariant_group` $invariantGroup^)?
     attr-dict `:` qualified(type($addr)) `->` type($res)
   }];
   string llvmBuilder = [{
@@ -399,6 +401,7 @@ def LLVM_LoadOp : LLVM_MemAccessOpBase<"load",
      # setSyncScopeCode
      # setAlignmentCode
      # setNonTemporalMetadataCode
+     # setInvariantGroupCode
      # setAccessGroupsMetadataCode
      # setAliasAnalysisMetadataCode;
   string mlirBuilder = [{
@@ -408,13 +411,15 @@ def LLVM_LoadOp : LLVM_MemAccessOpBase<"load",
         alignment, loadInst->isVolatile(),
         loadInst->hasMetadata(llvm::LLVMContext::MD_nontemporal),
         loadInst->hasMetadata(llvm::LLVMContext::MD_invariant_load),
+        loadInst->hasMetadata(llvm::LLVMContext::MD_invariant_group),
         convertAtomicOrderingFromLLVM(loadInst->getOrdering()),
         getLLVMSyncScope(loadInst));
   }];
   let builders = [
     OpBuilder<(ins "Type":$type, "Value":$addr,
       CArg<"unsigned", "0">:$alignment, CArg<"bool", "false">:$isVolatile,
       CArg<"bool", "false">:$isNonTemporal, CArg<"bool", "false">:$isInvariant,
+      CArg<"bool", "false">:$isInvariantGroup,
       CArg<"AtomicOrdering", "AtomicOrdering::not_atomic">:$ordering,
       CArg<"StringRef", "StringRef()">:$syncscope)>
   ];
@@ -431,6 +436,7 @@ def LLVM_StoreOp : LLVM_MemAccessOpBase<"store",
               OptionalAttr<I64Attr>:$alignment,
               UnitAttr:$volatile_,
               UnitAttr:$nontemporal,
+              UnitAttr:$invariantGroup,
               DefaultValuedAttr<
                 AtomicOrdering, "AtomicOrdering::not_atomic">:$ordering,
               OptionalAttr<StrAttr>:$syncscope);
@@ -464,6 +470,7 @@ def LLVM_StoreOp : LLVM_MemAccessOpBase<"store",
   let assemblyFormat = [{
     (`volatile` $volatile_^)? $value `,` $addr
     (`atomic` (`syncscope` `(` $syncscope^ `)`)? $ordering^)?
+    (`invariant_group` $invariantGroup^)?
     attr-dict `:` type($value) `,` qualified(type($addr))
   }];
   string llvmBuilder = [{
@@ -472,6 +479,7 @@ def LLVM_StoreOp : LLVM_MemAccessOpBase<"store",
      # setSyncScopeCode
      # setAlignmentCode
      # setNonTemporalMetadataCode
+     # setInvariantGroupCode
      # setAccessGroupsMetadataCode
      # setAliasAnalysisMetadataCode;
   string mlirBuilder = [{
@@ -480,13 +488,15 @@ def LLVM_StoreOp : LLVM_MemAccessOpBase<"store",
     $_op = $_builder.create<LLVM::StoreOp>($_location, $value, $addr,
         alignment, storeInst->isVolatile(),
         storeInst->hasMetadata(llvm::LLVMContext::MD_nontemporal),
+        storeInst->hasMetadata(llvm::LLVMContext::MD_invariant_group),
         convertAtomicOrderingFromLLVM(storeInst->getOrdering()),
         getLLVMSyncScope(storeInst));
   }];
   let builders = [
     OpBuilder<(ins "Value":$value, "Value":$addr,
       CArg<"unsigned", "0">:$alignment, CArg<"bool", "false">:$isVolatile,
       CArg<"bool", "false">:$isNonTemporal,
+      CArg<"bool", "false">:$isInvariantGroup,
       CArg<"AtomicOrdering", "AtomicOrdering::not_atomic">:$ordering,
       CArg<"StringRef", "StringRef()">:$syncscope)>
   ];

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -952,11 +952,11 @@ LogicalResult LoadOp::verify() {
 
 void LoadOp::build(OpBuilder &builder, OperationState &state, Type type,
                    Value addr, unsigned alignment, bool isVolatile,
-                   bool isNonTemporal, bool isInvariant,
+                   bool isNonTemporal, bool isInvariant, bool isInvariantGroup,
                    AtomicOrdering ordering, StringRef syncscope) {
   build(builder, state, type, addr,
         alignment ? builder.getI64IntegerAttr(alignment) : nullptr, isVolatile,
-        isNonTemporal, isInvariant, ordering,
+        isNonTemporal, isInvariant, isInvariantGroup, ordering,
         syncscope.empty() ? nullptr : builder.getStringAttr(syncscope),
         /*access_groups=*/nullptr,
         /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr,
@@ -991,11 +991,11 @@ LogicalResult StoreOp::verify() {
 
 void StoreOp::build(OpBuilder &builder, OperationState &state, Value value,
                     Value addr, unsigned alignment, bool isVolatile,
-                    bool isNonTemporal, AtomicOrdering ordering,
-                    StringRef syncscope) {
+                    bool isNonTemporal, bool isInvariantGroup,
+                    AtomicOrdering ordering, StringRef syncscope) {
   build(builder, state, value, addr,
         alignment ? builder.getI64IntegerAttr(alignment) : nullptr, isVolatile,
-        isNonTemporal, ordering,
+        isNonTemporal, isInvariantGroup, ordering,
         syncscope.empty() ? nullptr : builder.getStringAttr(syncscope),
         /*access_groups=*/nullptr,
         /*alias_scopes=*/nullptr, /*noalias_scopes=*/nullptr, /*tbaa=*/nullptr);

mlir/test/Dialect/LLVMIR/roundtrip.mlir

@@ -469,6 +469,20 @@ func.func @invariant_load(%ptr : !llvm.ptr) -> i32 {
   func.return %0 : i32
 }
 
+// CHECK-LABEL: @invariant_group_load
+func.func @invariant_group_load(%ptr : !llvm.ptr) -> i32 {
+  // CHECK: llvm.load %{{.+}} invariant_group {alignment = 4 : i64} : !llvm.ptr -> i32
+  %0 = llvm.load %ptr invariant_group {alignment = 4 : i64} : !llvm.ptr -> i32
+  func.return %0 : i32
+}
+
+// CHECK-LABEL: @invariant_group_store
+func.func @invariant_group_store(%val: i32, %ptr : !llvm.ptr) {
+  // CHECK: llvm.store %{{.+}}, %{{.+}} invariant_group : i32, !llvm.ptr
+  llvm.store %val, %ptr invariant_group : i32, !llvm.ptr
+  func.return
+}
+
 llvm.mlir.global external constant @_ZTIi() : !llvm.ptr
 llvm.func @bar(!llvm.ptr, !llvm.ptr, !llvm.ptr)
 llvm.func @__gxx_personality_v0(...) -> i32

mlir/test/Target/LLVMIR/Import/instructions.ll

@@ -383,6 +383,33 @@ define float @invariant_load(ptr %ptr) {
 
 ; // -----
 
+; CHECK-LABEL: @invariant_group_load
+; CHECK-SAME:  %[[PTR:[a-zA-Z0-9]+]]
+define float @invariant_group_load(ptr %ptr) {
+  ; CHECK:  %[[VAL:.+]] = llvm.load %[[PTR]] invariant_group {alignment = 4 : i64} : !llvm.ptr -> f32
+  %1 = load float, ptr %ptr, align 4, !invariant.group !0
+  ; CHECK:  llvm.return %[[VAL]]
+  ret float %1
+}
+
+!0 = !{}
+
+; // -----
+
+; CHECK-LABEL: @invariant_group_store
+; CHECK-SAME:  %[[VAL:[a-zA-Z0-9]+]]
+; CHECK-SAME:  %[[PTR:[a-zA-Z0-9]+]]
+define void @invariant_group_store(float %val, ptr %ptr) {
+  ; CHECK:  llvm.store %[[VAL]], %[[PTR]] invariant_group {alignment = 4 : i64} : f32, !llvm.ptr
+  store float %val, ptr %ptr, align 4, !invariant.group !0
+  ; CHECK:  llvm.return
+  ret void
+}
+
+!0 = !{}
+
+; // -----
+
 ; CHECK-LABEL: @atomic_load_store
 ; CHECK-SAME:  %[[PTR:[a-zA-Z0-9]+]]
 define void @atomic_load_store(ptr %ptr) {

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -1967,6 +1967,20 @@ llvm.func @nontemporal_store_and_load(%ptr : !llvm.ptr) -> i32 {
 
 // -----
 
+// Check that invariant group attribute is exported as metadata node.
+llvm.func @nontemporal_store_and_load(%ptr : !llvm.ptr) -> i32 {
+  %val = llvm.mlir.constant(42 : i32) : i32
+  // CHECK: store i32 42, ptr %{{.*}} !invariant.group ![[NODE:[0-9]+]]
+  llvm.store %val, %ptr invariant_group : i32, !llvm.ptr
+  // CHECK: %{{.*}} = load i32, ptr %{{.*}} !invariant.group ![[NODE]]
+  %1 = llvm.load %ptr invariant_group : !llvm.ptr -> i32
+  llvm.return %1 : i32
+}
+
+// CHECK: ![[NODE]] = !{}
+
+// -----
+
 llvm.func @atomic_store_and_load(%ptr : !llvm.ptr) {
   // CHECK: load atomic
   // CHECK-SAME:  acquire, align 4