Commit Graph

7 Commits

Author SHA1 Message Date
Adam Nemet 1428d41f9a [LoopDataPrefetch] Centralize the tuning cl::opts under the pass
This is effectively NFC, minus the renaming of the options
(-cyclone-prefetch-distance -> -prefetch-distance).

The change was requested by Tim in D17943.

llvm-svn: 264806
2016-03-29 23:45:52 +00:00
Adam Nemet 85fba39390 [LoopDataPrefetch] Make more member functions private, NFC.
llvm-svn: 264798
2016-03-29 22:40:02 +00:00
Adam Nemet 709e3046ee [LoopDataPrefetch] Add TTI to limit the number of iterations to prefetch ahead
Summary:
It can hurt performance to prefetch ahead too much.  Be conservative for
now and don't prefetch ahead more than 3 iterations on Cyclone.

Reviewers: hfinkel

Subscribers: llvm-commits, mzolotukhin

Differential Revision: http://reviews.llvm.org/D17949

llvm-svn: 263772
2016-03-18 00:27:43 +00:00
Adam Nemet 6d8beeca53 [LoopDataPrefetch/Aarch64] Allow selective prefetching of large-strided accesses
Summary:
And use this TTI for Cyclone.  As it was explained in the original RFC
(http://thread.gmane.org/gmane.comp.compilers.llvm.devel/92758), the HW
prefetcher work up to 2KB strides.

I am also adding tests for this and the previous change (D17943):

* Cyclone prefetching accesses with a large stride
* Cyclone not prefetching accesses with a small stride
* Generic Aarch64 subtarget not prefetching either

Reviewers: hfinkel

Subscribers: aemerson, rengolin, llvm-commits, mzolotukhin

Differential Revision: http://reviews.llvm.org/D17945

llvm-svn: 263771
2016-03-18 00:27:38 +00:00
Adam Nemet 34785ecff1 [LoopDataPrefetch] Add stats and debug output
llvm-svn: 262998
2016-03-09 05:33:21 +00:00
Adam Nemet bb3680bd85 [LoopDataPrefetch] If prefetch distance is not set, skip pass
This lets select sub-targets enable this pass.  The patch implements the
idea from the recent llvm-dev thread:
http://thread.gmane.org/gmane.comp.compilers.llvm.devel/94925

The goal is to enable the LoopDataPrefetch pass for the Cyclone
sub-target only within Aarch64.

Positive and negative tests will be included in an upcoming patch that
enables selective prefetching of large-strided accesses on Cyclone.

llvm-svn: 262844
2016-03-07 18:35:42 +00:00
Adam Nemet 9d9cb274ea [PPCLoopDataPrefetch] Move pass to Transforms/Scalar/LoopDataPrefetch. NFC
This patch is part of the work to make PPCLoopDataPrefetch
target-independent
(http://thread.gmane.org/gmane.comp.compilers.llvm.devel/92758).

Obviously the pass still only used from PPC at this point.  Subsequent
patches will start driving this from ARM64 as well.

Due to the previous patch most lines should show up as moved lines.

llvm-svn: 261265
2016-02-18 21:38:19 +00:00