[llvm] [DSE] Make iter order deterministic in removePartiallyOverlappedStores. NFC (PR #127678)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Björn Pettersson (bjope)

<details>
<summary>Changes</summary>

In removePartiallyOverlappedStores we iterate over InstOverlapIntervalsTy which is a DenseMap. Change that map into using MapVector to ensure that we apply the transforms in a deterministic order. I've only seen that the order matters if starting to use names for the instructions created when doing the transforms. But such things are a bit annoying when debugging etc.

---
Full diff: https://github.com/llvm/llvm-project/pull/127678.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp (+1-1) 


``````````diff
diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index a1649c276de83..f3b53e05c519e 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -174,7 +174,7 @@ static cl::opt<bool> EnableInitializesImprovement(
 // Helper functions
 //===----------------------------------------------------------------------===//
 using OverlapIntervalsTy = std::map<int64_t, int64_t>;
-using InstOverlapIntervalsTy = DenseMap<Instruction *, OverlapIntervalsTy>;
+using InstOverlapIntervalsTy = MapVector<Instruction *, OverlapIntervalsTy>;
 
 /// Returns true if the end of this instruction can be safely shortened in
 /// length.

``````````

</details>


https://github.com/llvm/llvm-project/pull/127678