On 2016-06-25 13:37, Rob Clark wrote:
Some games are sloppy.. perhaps because it is defined behavior for DX
or
perhaps because nv blob driver defaults things to zero.
So add driconf param to force uninitialized variables to default to
zero.
This issue was observed with rust, from steam store. But has surfaced
elsewhere in the past.
Signed-off-by: Rob Clark <robcl...@freedesktop.org>
---
Note that I left out the drirc bit, since not entirely sure how to
identify this game. (I don't actually have the game, just working off
of an apitrace)
Possibly worth mentioning that for the shaders using uninitialized vars
having zero-initializers lets constant-propagation get rid of a whole
lot of instructions. One shader I saw dropped to less than half of
it's original instruction count.
If the default for uninitialised variables is undefined, then with the
reported shader optimisations why bother with the (DRI) option when
zeroing could still essentially be classed as undefined?
Cuts the patch down to just the src/compiler/glsl/ast_to_hir.cpp change.
--
Alan.
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