[llvm] [RISCV] Order stack objects by access density (PR #217507)

[Pengcheng Wang via llvm-commits]

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@@ -2846,6 +2848,75 @@ void RISCVFrameLowering::inlineStackProbe(MachineFunction &MF,
   }
 }
 
+namespace {
+/// Bookkeeping record used while ordering local stack objects by access
+/// density. One record is created for each frame index passed to
+/// orderFrameObjects().
+struct RISCVFrameSortingObject {
+  int ObjectIndex;
+  uint64_t ObjectSize;
+  Align ObjectAlign;
+  uint64_t NumUses = 0;
+};
+} // end anonymous namespace
+
+void RISCVFrameLowering::orderFrameObjects(
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wangpc-pp wrote:

It seems we may mix scalar/RVV/varsize/... objects here? I don't know if we should keep the arrangement of these categories and sort the objects inside.

https://github.com/llvm/llvm-project/pull/217507