Re: [Mesa-dev] [PATCH 1/2] i965: Make DCE set null destinations on messages with side effects.

Kenneth Graunke writes: > (Co-authored by Matt Turner.) > > Image atomics, for example, return a value - but the shader may not > want to use it. We assigned a useless VGRF destination. This seemed > harmless, but it can actually be quite harmful. The register allocator

[Mesa-dev] [PATCH 1/2] i965: Make DCE set null destinations on messages with side effects.

(Co-authored by Matt Turner.) Image atomics, for example, return a value - but the shader may not want to use it. We assigned a useless VGRF destination. This seemed harmless, but it can actually be quite harmful. The register allocator has to assign that VGRF to a real register. It may