[PATCH] D139673: [AMDGPU][SIFrameLowering] Mark VGPR used for AGPR spills as reserved

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D139673#3982757 <https://reviews.llvm.org/D139673#3982757>, @arsenm wrote:

> We should work towards eliminating the special case handling of "spilling" between AGPRs and VGPRs. The allocator now knows they have a common allocatable class and introduces new vregs and copies as needed. We only still have this special handling because it breaks an optimization that works by accident now (which is unused subregister related)

Short of this, yes, any register used for special spill purposes needs to be reserved


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https://reviews.llvm.org/D139673