Commit Graph

2 Commits

Author SHA1 Message Date
Matt Arsenault 0e3d38937e AMDGPU: Remove SIPrepareScratchRegs
It does not work because of emergency stack slots.
This pass was supposed to eliminate dummy registers for the
spill instructions, but the register scavenger can introduce
more during PrologEpilogInserter, so some would end up
left behind if they were needed.

The potential for spilling the scratch resource descriptor
and offset register makes doing something like this
overly complicated. Reserve registers to use for the resource
descriptor and use them directly in eliminateFrameIndex.

Also removes creating another scratch resource descriptor
when directly selecting scratch MUBUF instructions.

The choice of which registers are reserved is temporary.
For now it attempts to pick the next available registers
after the user and system SGPRs.

llvm-svn: 254329
2015-11-30 21:15:53 +00:00
Matt Arsenault 0c90e9501e AMDGPU: Create emergency stack slots during frame lowering
Test has a bogus verifier error which will be fixed by later commits.

llvm-svn: 252327
2015-11-06 18:17:45 +00:00