[llvm] [CodeGen] Expansion of scalable vector reductions (PR #129214)

[Matt Arsenault via llvm-commits]

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@@ -12,22 +12,190 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/ExpandReductions.h"
+#include "llvm/Analysis/DomTreeUpdater.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instruction.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Pass.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
+#include <optional>
 
 using namespace llvm;
 
 namespace {
 
-bool expandReductions(Function &F, const TargetTransformInfo *TTI) {
-  bool Changed = false;
+void updateDomTreeForScalableExpansion(DominatorTree *DT, BasicBlock *Preheader,
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arsenm wrote:

Should use the DomTreeUpdater instead of doing it directly 

https://github.com/llvm/llvm-project/pull/129214