[Mesa-dev] [PATCH] i965: Fix brw_swap_cmod() for LE/GE comparisons.

[Chad Versace]

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On 06/16/2012 02:20 AM, Kenneth Graunke wrote:
> The idea here is to rewrite comparisons like 2 >= x with x <= 2; we want to simply exchange arguments, not negate
> the condition.  If equality was part of the original comparison, it should remain part of the swapped version.
> 
> This is the true cause of bug #50298.  It didn't manifest itself on Sandybridge because we embed the conditional
> modifier in the IF instruction rather than emitting a CMP.  All other platforms use CMP.
> 
> It also didn't manifest itself on the master branch because commit be5f27a84d ("glsl: Refine the loop instruction
> counting.") papered over the problem.
> 
> NOTE: This is a candidate for stable release branches.
> 
> Cc: Eric Anholt <eric at anholt.net> Cc: Chad Versace <chad.versace at linux.intel.com> Bugzilla:
> https://bugs.freedesktop.org/show_bug.cgi?id=50298 Signed-off-by: Kenneth Graunke <kenneth at whitecape.org> --- 
> src/mesa/drivers/dri/i965/brw_eu.c |    8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)


Oh, wow...

Reviewed-by: Chad Versace <chad.versace at linux.intel.com>


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