Commit Graph

4 Commits

Author SHA1 Message Date
Matt Arsenault 3b5d4aa258 GlobalISel: Infer nofpexcept flag during selection for non-strict ops
Match SelectionDAG's behavior of adding nofpexcept to out instructions
that may raise fp exceptions that are selected from instructions that
do not.
2020-06-05 13:59:46 -04:00
Matt Arsenault 4b4496312e AMDGPU: Start adding MODE register uses to instructions
This is the groundwork required to implement strictfp. For now, this
should be NFC for regular instructoins (many instructions just gain an
extra use of a reserved register). Regalloc won't rematerialize
instructions with reads of physical registers, but we were suffering
from that anyway with the exec reads.

Should add it for all the related FP uses (possibly with some
extras). I did not add it to either the gpr index mode instructions
(or every single VALU instruction) since it's a ridiculous feature
already modeled as an arbitrary side effect.

Also work towards marking instructions with FP exceptions. This
doesn't actually set the bit yet since this would start to change
codegen. It seems nofpexcept is currently not implied from the regular
IR FP operations. Add it to some MIR tests where I think it might
matter.
2020-05-27 14:47:00 -04:00
Matt Arsenault f9a42ed0a7 AMDGPU: Relax 32-bit SGPR register class
Mostly use SReg_32 instead of SReg_32_XM0 for arbitrary values. This
will allow the register coalescer to do a better job eliminating
copies to m0.

For GlobalISel, as a terrible hack, use SGPR_32 for things that should
use SCC until booleans are solved.

llvm-svn: 375267
2019-10-18 18:26:37 +00:00
Matt Arsenault 6ebf605851 AMDGPU: Use PatFrags to allow selecting custom nodes or intrinsics
This enables GlobalISel to handle various intrinsics. The custom node
pattern will be ignored, and the intrinsic will work. This will also
allow SelectionDAG to directly select the intrinsics, but as they are
all custom lowered to the nodes, this ends up leaving dead code in the
table.

Eventually either GlobalISel should add the equivalent of custom nodes
equivalent, or intrinsics should be directly used. These each have
different tradeoffs.

There are a few more to handle, but these are easy to handle
ones. Some others fail for other reasons.

llvm-svn: 371432
2019-09-09 18:10:31 +00:00