[Mlir-commits] [mlir] [MLIR][LLVM] Fold extract of extract (PR #125980)

[William Moses]

https://github.com/wsmoses created https://github.com/llvm/llvm-project/pull/125980

None

>From e20b3fd079fc5e0aeec8d3bd9dd49eec1f99e419 Mon Sep 17 00:00:00 2001
From: "William S. Moses" <gh at wsmoses.com>
Date: Wed, 5 Feb 2025 20:07:27 -0600
Subject: [PATCH] [MLIR][LLVM] Fold extract of extract

---
 mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp |  7 +++++++
 mlir/test/Dialect/LLVMIR/canonicalize.mlir | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
index a6e996f3fb810db..6d51042efcebdfb 100644
--- a/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
+++ b/mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
@@ -1898,6 +1898,13 @@ static Type getInsertExtractValueElementType(Type llvmType,
 }
 
 OpFoldResult LLVM::ExtractValueOp::fold(FoldAdaptor adaptor) {
+  if (auto extractValueOp = getContainer().getDefiningOp<ExtractValueOp>()) {
+    SmallVector<int64_t, 1> newPos(extractValueOp.getPosition());
+    newPos.append(getPosition().begin(), getPosition().end());
+    setPosition(newPos);
+    getContainerMutable().set(extractValueOp.getContainer());
+    return getResult();
+  }
   auto insertValueOp = getContainer().getDefiningOp<InsertValueOp>();
   OpFoldResult result = {};
   while (insertValueOp) {
diff --git a/mlir/test/Dialect/LLVMIR/canonicalize.mlir b/mlir/test/Dialect/LLVMIR/canonicalize.mlir
index 15f960167cb5f32..c509cd82227c295 100644
--- a/mlir/test/Dialect/LLVMIR/canonicalize.mlir
+++ b/mlir/test/Dialect/LLVMIR/canonicalize.mlir
@@ -84,6 +84,16 @@ llvm.func @fold_unrelated_extractvalue(%arr: !llvm.array<4 x f32>) -> f32 {
   llvm.return %3 : f32
 }
 
+// -----
+// CHECK-LABEL: fold_extract_extractvalue
+llvm.func @fold_extract_extractvalue(%arr: !llvm.struct<(i64, array<1 x ptr<1>>)>) -> !llvm.ptr<1> {
+  // CHECK: llvm.extractvalue %{{.*}}[1, 0] 
+  // CHECK-NOT: extractvalue
+  %a = llvm.extractvalue %arr[1] : !llvm.struct<(i64, array<1 x ptr<1>>)> 
+  %b = llvm.extractvalue %a[0] : !llvm.array<1 x ptr<1>> 
+  llvm.return %b : !llvm.ptr<1>
+}
+
 // -----
 
 // CHECK-LABEL: fold_bitcast