[llvm-branch-commits] [llvm] [AArch64] Prepare for split ZPR and PPR area allocation (NFCI) (PR #142391)

[Sander de Smalen via llvm-branch-commits]

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@@ -4294,24 +4396,32 @@ static int64_t determineSVEStackObjectOffsets(MachineFrameInfo &MFI,
       report_fatal_error(
           "Alignment of scalable vectors > 16 bytes is not yet supported");
 
+    int64_t &Offset = OffsetForObject(FI, ZPROffset, PPROffset);
     Offset = alignTo(Offset + MFI.getObjectSize(FI), Alignment);
     if (AssignOffsets)
       Assign(FI, -Offset);
   }
 
-  return Offset;
+  PPROffset = alignTo(PPROffset, Align(16U));
+  ZPROffset = alignTo(ZPROffset, Align(16U));
+
+  if (&ZPROffset != &PPROffset) {
+    // SplitSVEObjects (PPRs and ZPRs allocated to separate areas).
+    return SVEStackSizes{ZPROffset, PPROffset};
+  }
+  // When SplitSVEObjects is disabled just attribute all the stack to ZPRs.
+  // Determining the split is not necessary.
+  return SVEStackSizes{ZPROffset, 0};
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sdesmalen-arm wrote:

When you use an instance of the return type (`SVEStackSizes`) instead of `ZPRStack` and `PPRStack`, then you can just return that struct at the end of this function.

https://github.com/llvm/llvm-project/pull/142391