[llvm-branch-commits] [llvm] [AArch64][SME] Support split ZPR and PPR area allocation (PR #142392)

[Sander de Smalen via llvm-branch-commits]

================
@@ -56,16 +56,19 @@
 // | async context if needed           |
 // | (a.k.a. "frame record")           |
 // |-----------------------------------| <- fp(=x29)
-// |   <hazard padding>                |
-// |-----------------------------------|
-// |                                   |
-// | callee-saved fp/simd/SVE regs     |
-// |                                   |
-// |-----------------------------------|
-// |                                   |
-// |        SVE stack objects          |
-// |                                   |
-// |-----------------------------------|
+//        Default SVE stack layout                 Split SVE objects
+//   (aarch64-split-sve-objects=false)      (aarch64-split-sve-objects=true)
+// |-----------------------------------|  |-----------------------------------|
+// |         <hazard padding>          |  | callee-saved PPR registers        |
+// |-----------------------------------|  |-----------------------------------|
+// |                                   |  |         PPR stack objects         |
+// | callee-saved fp/simd/SVE regs     |  |-----------------------------------|
+// |                                   |  |         <hazard padding>          |
+// |-----------------------------------|  |-----------------------------------|
+// |                                   |  | callee-saved ZPR registers        |
----------------
sdesmalen-arm wrote:

nit: Maybe also add a comment here to explain that any FPR callee-saves will get promoted to ZPR callee-saves?

https://github.com/llvm/llvm-project/pull/142392