[Mlir-commits] [mlir] [mlir][LLVM] Add invariant load attribute to LLVM's CallIntrinsicOp (PR #223142)

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<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir

Author: Ayokunle Amodu (ayokunle321)

<details>
<summary>Changes</summary>

In LLVM IR, the `llvm.amdgcn.ptr.s.buffer.load` intrinsic has an invariant load metadata attached. LLVMCallIntrinsicOp (an op from the LLVM dialect that maps LLVM IR intrinsic) had no corresponding attribute. This patch therefore adds the invariant attribute to the op.

Assisted by: Claude Opus 5

---
Full diff: https://github.com/llvm/llvm-project/pull/223142.diff


3 Files Affected:

- (modified) mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td (+2-1) 
- (modified) mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp (+5) 
- (modified) mlir/test/Target/LLVMIR/llvmir.mlir (+11) 


``````````diff
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
index 9811b93539a9b..05d3663a796ad 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -2666,7 +2666,8 @@ def LLVM_CallIntrinsicOp
                        DenseI32ArrayAttr:$op_bundle_sizes,
                        OptionalAttr<ArrayAttr>:$op_bundle_tags,
                        OptionalAttr<DictArrayAttr>:$arg_attrs,
-                       OptionalAttr<DictArrayAttr>:$res_attrs);
+                       OptionalAttr<DictArrayAttr>:$res_attrs,
+                       UnitAttr:$invariant);
   let results = (outs Optional<LLVM_Type>:$results);
   let llvmBuilder = [{
     return convertCallLLVMIntrinsicOp(op, builder, moduleTranslation);
diff --git a/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp b/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
index 0c715da6ba954..1cd96fd6bf3ba 100644
--- a/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp
@@ -205,6 +205,11 @@ convertCallLLVMIntrinsicOp(CallIntrinsicOp op, llvm::IRBuilderBase &builder,
   if (failed(moduleTranslation.convertArgAndResultAttrs(op, inst)))
     return failure();
 
+  if (op.getInvariant()) {
+    llvm::MDNode *metadata = llvm::MDNode::get(inst->getContext(), {});
+    inst->setMetadata(llvm::LLVMContext::MD_invariant_load, metadata);
+  }
+
   if (op.getNumResults() == 1)
     moduleTranslation.mapValue(op->getResults().front()) = inst;
   return success();
diff --git a/mlir/test/Target/LLVMIR/llvmir.mlir b/mlir/test/Target/LLVMIR/llvmir.mlir
index 84d892876d36a..8f83c1d1f60ef 100644
--- a/mlir/test/Target/LLVMIR/llvmir.mlir
+++ b/mlir/test/Target/LLVMIR/llvmir.mlir
@@ -3486,6 +3486,17 @@ llvm.func @call_intrin_with_opbundle(%arg0 : !llvm.ptr) {
 
 // -----
 
+llvm.func @call_intrin_invariant(%arg0 : !llvm.ptr<8>, %arg1 : i32) -> f32 {
+  %0 = llvm.mlir.constant(0 : i32) : i32
+  %1 = llvm.call_intrinsic "llvm.amdgcn.ptr.s.buffer.load.f32"(%arg0, %arg1, %0) {invariant} : (!llvm.ptr<8>, i32, i32) -> f32
+  llvm.return %1 : f32
+}
+
+// CHECK-LABEL: define float @call_intrin_invariant(
+//      CHECK:   call float @llvm.amdgcn.ptr.s.buffer.load.f32({{.*}}), !invariant.load
+
+// -----
+
 module {
   llvm.module_flags [#llvm.mlir.module_flag<error, "wchar_size", 4 : i32>,
                      #llvm.mlir.module_flag<min, "PIC Level", 2 : i32>,

``````````

</details>


https://github.com/llvm/llvm-project/pull/223142