[Mesa-dev] [PATCH] i965/fs: Follow pow(16) instructions with a NOP.

Matt Turner mattst88 at gmail.com
Wed May 4 06:30:34 UTC 2016

On Tue, May 3, 2016 at 3:28 PM, Francisco Jerez <currojerez at riseup.net> wrote:
> Matt Turner <mattst88 at gmail.com> writes:
>> Beginning with commit 7b208a73, Unigine Valley began hanging the GPU on
>> Gen >= 8 platforms. This patch avoids the GPU hangs, but does not
>> implement a full work around for the restriction (dispatch_width == 16
>> is an imperfect proxy).
> Sounds like for a proper fix we could just check the last instruction in
> the assembly at the top of the generator loop and emit a NOP in cases
> where the previous instruction is one of the affected math opcodes?

If I assume correctly that you mean "so we can check if the following
instruction has two destination registers", then yes that would be

What's the best way to check that?
inst->dst.component_size(inst->exec_size) > REG_SIZE ?

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