[AArch64] Fold some filled/spilled subreg COPYs
Summary:
Extend AArch64 foldMemoryOperandImpl() to handle folding spills of
subreg COPYs with read-undef defs like:
%vreg0:sub_32<def,read-undef> = COPY %WZR; GPR64:%vreg0
by widening the spilled physical source reg and generating:
STRXui %XZR <fi#0>
as well as folding fills of similar COPYs like:
%vreg0:sub_32<def,read-undef> = COPY %vreg1; GPR64:%vreg0, GPR32:%vreg1
by generating:
%vreg0:sub_32<def,read-undef> = LDRWui <fi#0>
Reviewers: MatzeB, qcolombet
Subscribers: aemerson, rengolin, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D27425
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@291180 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed