Commit Graph

7 Commits

Author SHA1 Message Date
Chandler Carruth f3bd8ddedb Revert r301950: SpeculativeExecution: Stop using whitelist for costs
This pass doesn't correctly handle testing for when it is legal to hoist
arbitrary instructions. The whitelist happens to make it safe, so before
it is removed the pass's legality checks will need to be enhanced.

Details have been added to the code review thread for the patch.

llvm-svn: 302640
2017-05-10 12:30:07 +00:00
Matt Arsenault 9ac7d6be3c SpeculativeExecution: Stop using whitelist for costs
Just let TTI's cost do this instead of arbitrarily restricting
this.

llvm-svn: 301950
2017-05-02 18:02:18 +00:00
Matt Arsenault ef00283425 SpeculativeExecution: Allow speculating more inst types
Partial step towards removing the whitelist and only
using TTI's cost.

llvm-svn: 285438
2016-10-28 20:00:33 +00:00
Michael Kuperstein c40618610f [PM] Port SpeculativeExecution to the new PM
Differential Revision: https://reviews.llvm.org/D23033

llvm-svn: 277393
2016-08-01 21:48:33 +00:00
Justin Lebar f04e678e36 Move divergent-target test into CodeGen/NVPTX because it requires an NVPTX target.
llvm-svn: 266403
2016-04-15 01:20:52 +00:00
Justin Lebar cad81cf6b3 [Speculation] Add a SpeculativeExecution mode where the pass does nothing unless TTI::hasBranchDivergence() is true.
Summary:
This lets us add this pass to the IR pass manager unconditionally; it
will simply not do anything on targets without branch divergence.

Reviewers: tra

Subscribers: llvm-commits, jingyue, rnk, chandlerc

Differential Revision: http://reviews.llvm.org/D18625

llvm-svn: 266398
2016-04-15 00:32:09 +00:00
Jingyue Wu 154eb5aa1d Add a speculative execution pass
Summary:
This is a pass for speculative execution of instructions for simple if-then (triangle) control flow. It's aimed at GPUs, but could perhaps be used in other contexts. Enabling this pass gives us a 1.0% geomean improvement on Google benchmark suites, with one benchmark improving 33%.

Credit goes to Jingyue Wu for writing an earlier version of this pass.

Patched by Bjarke Roune. 

Test Plan:
This patch adds a set of tests in test/Transforms/SpeculativeExecution/spec.ll
The pass is controlled by a flag which defaults to having the pass not run.

Reviewers: eliben, dberlin, meheff, jingyue, hfinkel

Reviewed By: jingyue, hfinkel

Subscribers: majnemer, jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D9360

llvm-svn: 237459
2015-05-15 17:54:48 +00:00