[llvm] [AArch64] New subtarget features to control ldp and stp formation, fo… (PR #66098)

[Manos Anagnostakis via llvm-commits]

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@@ -2159,6 +2171,24 @@ bool AArch64LoadStoreOpt::tryToPairLdStInst(MachineBasicBlock::iterator &MBBI) {
     // Keeping the iterator straight is a pain, so we let the merge routine tell
     // us what the next instruction is after it's done mucking about.
     auto Prev = std::prev(MBBI);
+
+    // Get the needed alignments to check them if
+    // ldp-aligned-only/stp-aligned-only features are opted.
+    uint64_t MemAlignment = MemOp->getAlign().value();
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manosanaggh wrote:

I think I will move it right under the call to isCandidateToMergeOrPair and not inside it, because I do not want to alter the outcome of the function for merges (merge != pair).

https://github.com/llvm/llvm-project/pull/66098