[Mesa-dev] [PATCH] i965/fs: Don't perform CSE on inst HW_REG dests (unless it's null)

[Eric Anholt]

Matt Turner <mattst88 at gmail.com> writes:

> Commit b16b3c87 began performing CSE on CMP instructions with null
> destinations. I relaxed the restrictions a bit too much, thereby
> allowing CSE to be performed on instructions with, for instance, an
> explicit accumulator destination.
>
> This broke the arb_gpu_shader5/fs-imulExtended shader tests because
> they emit MUL instructions with the accumulator as the destination. CSE
> would instead cause the MUL to write to a GRF, which is lower precision
> than the accumulator.

Reviewed-by: Eric Anholt <eric at anholt.net>

(mark as 10.0 candidate)
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