Bug 94445

Summary:	Tonga llvm assert since RegisterCoalescer: Need to check DstReg+SrcReg for missing undef flags
Product:	Mesa	Reporter:	Andy Furniss <adf.lists>
Component:	Drivers/Gallium/radeonsi	Assignee:	Default DRI bug account <dri-devel>
Status:	RESOLVED FIXED	QA Contact:	Default DRI bug account <dri-devel>
Severity:	normal
Priority:	medium	CC:	vedran
Version:	git
Hardware:	x86-64 (AMD64)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Attachments:	R600_DEBUG=vs,ps bz2 Failing shader

Description Andy Furniss 2016-03-08 18:27:24 UTC

R9285 since llvm commit 

commit 817178adc78bbd36ba635d3147cca53070558def
Author: Matthias Braun <matze@braunis.de>
Date:   Sat Mar 5 04:36:10 2016 +0000

    RegisterCoalescer: Need to check DstReg+SrcReg for missing undef flags
    
    copy coalescing with enabled subregister liveness can reveal undef uses,
    previously this was only checked for the SrcReg in updateRegDefsUses()
    but we need to check DstReg as well.
    
    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262767 91177308-0d34-0410-b5e6-96231b3b80d8

Unigine Valley will assert at start of rendering.

valley_x64: /mnt/sdb1/Gits/llvm/lib/CodeGen/MachineScheduler.cpp:1046: void llvm::ScheduleDAGMILive::updatePressureDiffs(llvm::ArrayRef<llvm::RegisterMaskPair>): Assertion `VNI && "No live value at use."' failed.


Other demos don't trigger this.

Valley is running 1920x1080 fullscreen ultra quality + 8x AA.

Comment 1 Michel Dänzer 2016-03-09 01:19:01 UTC

Please attach the stderr output from running Valley with R600_DEBUG=vs,ps .

Did you report this to Matthias and/or the llvm-commits mailing list?

Comment 2 Andy Furniss 2016-03-09 22:07:16 UTC

Created attachment 122186 [details]
R600_DEBUG=vs,ps bz2

Comment 3 Andy Furniss 2016-03-09 22:09:17 UTC

I am not on/familiar with any llvm lists.

Adding Matthias to cc doesn't work for me here - I guess it only does fdo known addresses?

Comment 4 Vedran Miletić 2016-03-17 15:10:33 UTC

Happens on Bonaire and Kabini as well when running GROMACS OpenCL. I can provide .ll if useful.

Comment 5 Nicolai Hähnle 2016-03-17 17:43:35 UTC

Created attachment 122385 [details]
Failing shader

The shader still fails to compile. I've contacted Matthias about this.

Comment 6 Vedran Miletić 2016-03-26 10:27:45 UTC

(In reply to Nicolai Hähnle from comment #5)
> Created attachment 122385 [details]
> Failing shader
> 
> The shader still fails to compile. I've contacted Matthias about this.

Any news?

Comment 7 Andy Furniss 2016-03-30 23:48:43 UTC

Working for me with current llvm/mesa.

Comment 8 Andy Furniss 2016-03-31 15:13:12 UTC

Fixing commit = 

commit d3adac51fcce66e8c79b77299fef9e5f6c4c646e
Author: Tom Stellard <thomas.stellard@amd.com>
Date:   Wed Mar 30 16:35:09 2016 +0000

    AMDGPU/SI: Enable lanemask tracking in misched
    
    Summary:
    This results in higher register usage, but should make it easier for
    the compiler to hide latency.
    
    This pass is a prerequisite for some more scheduler improvements, and I
    think the increase register usage with this patch is acceptable, because
    when combined with the scheduler improvements, the total register usage
    will decrease.
    
    shader-db stats:
    
    2382 shaders in 478 tests
    Totals:
    SGPRS: 48672 -> 49088 (0.85 %)
    VGPRS: 34148 -> 34847 (2.05 %)
    Code Size: 1285816 -> 1289128 (0.26 %) bytes
    LDS: 28 -> 28 (0.00 %) blocks
    Scratch: 492544 -> 573440 (16.42 %) bytes per wave
    Max Waves: 6856 -> 6846 (-0.15 %)
    Wait states: 0 -> 0 (0.00 %)
    
    Depends on D18451
    
    Reviewers: nhaehnle, arsenm
    
    Subscribers: arsenm, llvm-commits
    
    Differential Revision: http://reviews.llvm.org/D18452
    
    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264876 91177308-0d34-0410-b5e6-96231b3b80d8

Comment 9 Andy Furniss 2016-03-31 15:19:34 UTC

Leaving open to see if other peoples test cases are also fixed.

Or maybe the "fixing" commit is just hiding some other issue?

Comment 10 Vedran Miletić 2016-03-31 16:53:44 UTC

(In reply to Andy Furniss from comment #7)
> Working for me with current llvm/mesa.

Same here, tested on Kabini and Bonaire.

Comment 11 Nicolai Hähnle 2016-06-23 20:22:35 UTC

This has been fixed for some time.

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