Commit Graph

4 Commits

Author SHA1 Message Date
Nicolai Haehnle 56d0ed2a50 [DA] GPUDivergenceAnalysis for unstructured GPU kernels
Summary:
This is patch #3 of the new DivergenceAnalysis

  <https://lists.llvm.org/pipermail/llvm-dev/2018-May/123606.html>

The GPUDivergenceAnalysis is intended to eventually supersede the existing
LegacyDivergenceAnalysis. The existing LegacyDivergenceAnalysis produces
incorrect results on unstructured Control-Flow Graphs:

  <https://bugs.llvm.org/show_bug.cgi?id=37185>

This patch adds the option -use-gpu-divergence-analysis to the
LegacyDivergenceAnalysis to turn it into a transparent wrapper for the
GPUDivergenceAnalysis.

Reviewers: nhaehnle

Reviewed By: nhaehnle

Subscribers: jholewinski, jvesely, jfb, llvm-commits, alex-t, sameerds, arsenm, nhaehnle

Differential Revision: https://reviews.llvm.org/D53493

llvm-svn: 348048
2018-11-30 22:55:20 +00:00
Nicolai Haehnle 35617ed4cb [NFC] Rename the DivergenceAnalysis to LegacyDivergenceAnalysis
Summary:
This is patch 1 of the new DivergenceAnalysis (https://reviews.llvm.org/D50433).

The purpose of this patch is to free up the name DivergenceAnalysis for the new generic
implementation. The generic implementation class will be shared by specialized
divergence analysis classes.

Patch by: Simon Moll

Reviewed By: nhaehnle

Subscribers: jvesely, jholewinski, arsenm, nhaehnle, mgorny, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D50434

Change-Id: Ie8146b11be2c50d5312f30e11c7a3036a15b48cb
llvm-svn: 341071
2018-08-30 14:21:36 +00:00
Tim Renouf f3d8295105 DivergenceAnalysis: added debug output
Summary:
This commit does two things:

1. modified the existing DivergenceAnalysis::dump() so it dumps the
   whole function with added DIVERGENT: annotations;

2. added code to do that dump if the appropriate -debug-only option is
   on.

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D47700

Change-Id: Id97b605aab1fc6f5a11a20c58a99bbe8c565bf83
llvm-svn: 336998
2018-07-13 13:13:30 +00:00
Nicolai Haehnle 13d90f324c [DivergenceAnalysis] Treat PHI with incoming undef as constant
Summary:
If a PHI has an incoming undef, we can pretend that it is equal to one
non-undef, non-self incoming value.

This is particularly relevant in combination with the StructurizeCFG
pass, which introduces PHI nodes with undefs. Previously, this lead to
branch conditions that were uniform before StructurizeCFG to become
non-uniform afterwards, which confused the SIAnnotateControlFlow
pass.

This fixes a crash when Mesa radeonsi compiles a shader from
dEQP-GLES3.functional.shaders.switch.switch_in_for_loop_dynamic_vertex

Reviewers: arsenm, tstellarAMD, jingyue

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D19013

llvm-svn: 266347
2016-04-14 17:42:47 +00:00