Bug 89095 - [SNB/IVB/BYT Bisected]Webglc conformance/glsl/functions/glsl-function-mix-float.html fails
Summary: [SNB/IVB/BYT Bisected]Webglc conformance/glsl/functions/glsl-function-mix-flo...
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/i965 (show other bugs)
Version: unspecified
Hardware: All Linux (All)
: high normal
Assignee: Matt Turner
QA Contact: Intel 3D Bugs Mailing List
URL: http://lists.freedesktop.org/archives...
Keywords: patch
Depends on:
Reported: 2015-02-12 02:00 UTC by lu hua
Modified: 2015-03-13 07:04 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:


Description lu hua 2015-02-12 02:00:16 UTC
System Environment:
Platform: SNB
Libdrm:         (master)libdrm-2.4.59-10-gde8532dd8359dfdaba839ff61fc9e2f05eaf57d3
Mesa:           (master)ea0f0eb6c0a8b20bcce50c63170df94892a51142
Xserver:        (master)xorg-server-1.17.0-2-g20079c36cf7d377938ca5478447d8b9045cb7d43
Xf86_video_intel: (master)2.99.917-111-g8ef3fdacac05ee93b685a93f6664696d026e889e
Libva:          (master)f9741725839ea144e9a6a1827f74503ee39946c3
Libva_intel_driver:   (master)9a20d6c34cb65e5b85dd16d6c8b3a215c5972b18
Kernel:  drm-intel-nightly/34f9b98d3e64c8df349816115ea5a560a6763ce8

ug detailed description:
It fails on SNB/IVB/BYT with mesa master branch, works well on 10.4 branch.
conformance/glsl/functions/glsl-function-mix-gentype.html also fails with the same bisect commit.

Bisect shows: 3d581f99963dea7e93a2f8fd819410da02c1cb7f is the first bad commit is the first bad commit.
commit 3d581f99963dea7e93a2f8fd819410da02c1cb7f
Author:     Matt Turner <mattst88@gmail.com>
AuthorDate: Fri Dec 19 21:35:56 2014 -0800
Commit:     Matt Turner <mattst88@gmail.com>
CommitDate: Tue Feb 10 17:47:37 2015 -0800

    i965/vec4: Emit MADs from (x + -(y * z)).

    Same as commit c4fab711 to the fs backend.

    total instructions in shared programs: 5945998 -> 5945788 (-0.00%)
    instructions in affected programs:     74665 -> 74455 (-0.28%)
    helped:                                399
    HURT:                                  180

    It hurts some programs because we make no attempts in the vec4 backend
    to avoid MADs if they have constant (or vector uniform) arguments.

    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

Reproduce steps:
1. xinit
2. go to https://www.khronos.org/registry/webgl/conformance-suites/1.0.2/webgl-conformance-tests.html run conformance/glsl/functions/glsl-function-mix-float.html
Comment 1 Matt Turner 2015-02-27 19:02:19 UTC
I'll send a patch for this shortly.
Comment 2 Matt Turner 2015-02-27 19:36:27 UTC
Patch sent to the mailing list.
Comment 3 Matt Turner 2015-02-28 04:25:02 UTC
Should be fixed by:

commit d528907fd2950c7bb968fff66dd79863cd128890
Author: Matt Turner <mattst88@gmail.com>
Date:   Fri Feb 27 10:59:17 2015 -0800

    i965: Avoid applying negate to wrong MAD source.
Comment 4 lu hua 2015-03-02 08:48:29 UTC
Comment 5 lu hua 2015-03-13 07:04:25 UTC
Edit summary, track bisected bug easily.

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