Cover all the missing cases and add very detailed tests for each rule.
In summary:
- Flat and Scratch, addrspace(0) and addrspace(5), loads are always
divergent.
- Global and Constant, addrspace(1) and addrspace(4), have real uniform
loads, s_load, but require additional checks for align and flags in mmo.
For not natural align or not uniform mmo do uniform-in-vgpr lowering.
- Private, addrspace(3), only has instructions for divergent load, for
uniform do uniform-in-vgpr lowering.
- Store rules are simplified using Ptr32 and Ptr64.
All operands need to be vgpr.
Some tests have code size regression since they use more sgpr instructions,
marked with FixMe comment to get back to later.
Recent upstream trends have moved away from explicitly using `-verify-machineinstrs`, as it's already covered by the expensive checks. This PR removes almost all `-verify-machineinstrs` from tests in `llvm/test/CodeGen/AMDGPU/*.ll`, leaving only those tests where its removal currently causes failures.
This patch dismantles G_SHUFFLE_VECTOR before lowering. The original
lowering would emit extract vector element ops. We found that by using
unmerged values the build vector op combine could find ways to fold.
Only enabled on AMDGPU.
This resolves#123631
