Bug 89095

Summary:	[SNB/IVB/BYT Bisected]Webglc conformance/glsl/functions/glsl-function-mix-float.html fails
Product:	Mesa	Reporter:	lu hua <huax.lu>
Component:	Drivers/DRI/i965	Assignee:	Matt Turner <mattst88>
Status:	VERIFIED FIXED	QA Contact:	Intel 3D Bugs Mailing List <intel-3d-bugs>
Severity:	normal
Priority:	high	CC:	idr
Version:	unspecified	Keywords:	patch
Hardware:	All
OS:	Linux (All)
URL:	http://lists.freedesktop.org/archives/mesa-dev/2015-February/078057.html
Whiteboard:
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

Verified.Fixed.

Comment 5 lu hua 2015-03-13 07:04:25 UTC

Edit summary, track bisected bug easily.

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