[flang-commits] [compiler-rt] [flang] [llvm] [AArch64] fix trampoline implementation: use X15 (PR #126743)

[Eli Friedman via flang-commits]

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@@ -1,35 +1,26 @@
-; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+;; Testing that nest uses x15 on all calling conventions (except Arm64EC)
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efriedma-quic wrote:

Oh, you mean the CC_AArch64_Arm64EC_Thunk convention.  Probably should make the comment specifically mention you're referring to thunks.

I guess to make trampolines work on arm64ec, the trampoline itself would actually have to be x86-64 code... which can't even access x15, so yeah, x4 makes sense.  The thunk would then copy from x4 to x15.  I don't expect you to implement this, but maybe stick a report_fatal_error somewhere if someone tries to use nest with arm64ec.

https://github.com/llvm/llvm-project/pull/126743