[PATCH] D111637: [AMDGPU] Changes the AMDGPU_Gfx calling convention by making the SGPRs 4..29 callee-save. This is to avoid superfluous s_movs when executing amdgpu_gfx function calls as the callee is likely not going to change the argument values.

[Thomas Symalla via Phabricator via llvm-commits]

tsymalla created this revision.
tsymalla added reviewers: dstuttard, foad, tpr, Flakebi.
Herald added subscribers: kerbowa, hiraditya, t-tye, yaxunl, nhaehnle, jvesely, kzhuravl, arsenm, qcolombet, MatzeB.
tsymalla requested review of this revision.
Herald added subscribers: llvm-commits, wdng.
Herald added a project: LLVM.

This patch changes the AMDGPU_Gfx calling convention. It defines the SGPR registers s[4:29] as callee-save and leaves some SGPRs usable for callers. The intention is to avoid unneccessary s_mov instructions for arguments the caller would otherwise save and restore in these registers.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D111637

Files:
  llvm/lib/Target/AMDGPU/AMDGPUCallingConv.td
  llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
  llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-call-non-fixed.ll
  llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-call-return-values.ll
  llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-call.ll
  llvm/test/CodeGen/AMDGPU/GlobalISel/irtranslator-indirect-call.ll
  llvm/test/CodeGen/AMDGPU/amdpal-callable.ll
  llvm/test/CodeGen/AMDGPU/gfx-callable-argument-types.ll
  llvm/test/CodeGen/AMDGPU/gfx-callable-preserved-registers.ll
  llvm/test/CodeGen/AMDGPU/gfx-callable-return-types.ll
  llvm/test/CodeGen/AMDGPU/indirect-call.ll
  llvm/test/CodeGen/AMDGPU/pal-simple-indirect-call.ll
  llvm/test/CodeGen/AMDGPU/tail-call-amdgpu-gfx.ll
  llvm/test/CodeGen/AMDGPU/vgpr-liverange-ir.ll
  llvm/test/CodeGen/AMDGPU/vgpr-liverange.ll
  llvm/test/CodeGen/AMDGPU/wwm-reserved-spill.ll