[llvm] [AArch64][SVE] Pair SVE fill/spill into LDP/STP with -msve-vector-bits=128. (PR #134068)

[Paul Walker via llvm-commits]

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@@ -2840,6 +2883,9 @@ bool AArch64LoadStoreOpt::optimizeBlock(MachineBasicBlock &MBB,
     updateDefinedRegisters(*MBBI, DefinedInBB, TRI);
     if (TII->isPairableLdStInst(*MBBI) && tryToPairLdStInst(MBBI))
       Modified = true;
+    else if (CanPairFillSpill && isPairableFillSpillInst(*MBBI) &&
+             tryToPairLdStInst(MBBI))
+      Modified = true;
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paulwalker-arm wrote:

It is necessary to have a separate path for SVE rather than extending isPairableLdStInst?  I can see isPairableLdStInst is also used to group related instructions together, which is something we might want in the future, assuming it doesn't already come for free.

https://github.com/llvm/llvm-project/pull/134068