SuccessChanges

Summary

  1. [AMDGPU] Enable SGPR copy folding (details)
Commit 4c0251da149c99f49550d6c938e6e7f45075194d by Stanislav.Mekhanoshin
[AMDGPU] Enable SGPR copy folding
That used to fail in the last testcase function because after
%0:sreg_64.sub0 was folded into %3:sreg_32_xm0_xexec COPY, it was
further folded into S_STORE_DWORD_IMM. Its legal effective subreg class
is SReg_32 while instruction expects more restricted SReg_32_XM0_EXEC.
However, SIInstrInfo::isLegalRegOperand() passed the legality check and
it was caught in the verifier.
Borrowed code from the verifier to check for RC legality.
Differential Revision: https://reviews.llvm.org/D69445
The file was addedllvm/test/CodeGen/AMDGPU/fold-sgpr-copy.mir
The file was modifiedllvm/lib/Target/AMDGPU/SIFoldOperands.cpp
The file was modifiedllvm/lib/Target/AMDGPU/SIInstrInfo.cpp