[llvm-branch-commits] [mlir] [mlir][OpenMP] Convert reduction alloc region to LLVMIR (PR #102524)

[Mats Petersson via llvm-branch-commits]

================
@@ -594,45 +594,85 @@ convertOmpOrderedRegion(Operation &opInst, llvm::IRBuilderBase &builder,
 
 /// Allocate space for privatized reduction variables.
 template <typename T>
-static void allocByValReductionVars(
-    T loop, ArrayRef<BlockArgument> reductionArgs, llvm::IRBuilderBase &builder,
-    LLVM::ModuleTranslation &moduleTranslation,
-    llvm::OpenMPIRBuilder::InsertPointTy &allocaIP,
-    SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls,
-    SmallVectorImpl<llvm::Value *> &privateReductionVariables,
-    DenseMap<Value, llvm::Value *> &reductionVariableMap,
-    llvm::ArrayRef<bool> isByRefs) {
+static LogicalResult
+allocReductionVars(T loop, ArrayRef<BlockArgument> reductionArgs,
+                   llvm::IRBuilderBase &builder,
+                   LLVM::ModuleTranslation &moduleTranslation,
+                   llvm::OpenMPIRBuilder::InsertPointTy &allocaIP,
+                   SmallVectorImpl<omp::DeclareReductionOp> &reductionDecls,
+                   SmallVectorImpl<llvm::Value *> &privateReductionVariables,
+                   DenseMap<Value, llvm::Value *> &reductionVariableMap,
+                   llvm::ArrayRef<bool> isByRefs) {
   llvm::IRBuilderBase::InsertPointGuard guard(builder);
   builder.SetInsertPoint(allocaIP.getBlock()->getTerminator());
 
+  // delay creating stores until after all allocas
+  SmallVector<std::pair<llvm::Value *, llvm::Value *>> storesToCreate;
+  storesToCreate.reserve(loop.getNumReductionVars());
+
   for (std::size_t i = 0; i < loop.getNumReductionVars(); ++i) {
-    if (isByRefs[i])
-      continue;
-    llvm::Value *var = builder.CreateAlloca(
-        moduleTranslation.convertType(reductionDecls[i].getType()));
-    moduleTranslation.mapValue(reductionArgs[i], var);
-    privateReductionVariables[i] = var;
-    reductionVariableMap.try_emplace(loop.getReductionVars()[i], var);
+    Region &allocRegion = reductionDecls[i].getAllocRegion();
+    if (isByRefs[i]) {
+      if (allocRegion.empty())
----------------
Leporacanthicus wrote:

What does allocRegion empty mean here? It's not been created? If so, where does the alloca go?

https://github.com/llvm/llvm-project/pull/102524