[PATCH] D124836: [AArch64] Add support for -fzero-call-used-regs

[Sander de Smalen via Phabricator via cfe-commits]

sdesmalen added inline comments.


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Comment at: llvm/lib/Target/AArch64/AArch64RegisterInfo.td:1398
+                                 (sequence "W%u", 0, 7))>;
+def FPR8_ARG : RegisterClass<"AArch64", [untyped], 8, (trunc FPR8, 7)> {
+  let Size = 8;
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Should this feature/attribute work with other calling conventions? If so, then it's probably best not to hard-code these values here, but rather to get them from the chosen calling convention for that particular function. The supported calling conventions are defined in AArch64CallingConvention.td.

For example, you could iterate all registers in GPR64/FPR128/ZPR/PPR register classes and zero their values if they are not marked as callee saved. You can query this information from the call by looking at it's callee-saved regmask (see for example `CSR_AArch64_AAPCS_RegMask` to see how those are defined defined).


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D124836/new/

https://reviews.llvm.org/D124836