Zvi Rackover 3438d07f09 LoopVectorize: MaxVF should not be larger than the loop trip count ...

Summary:
Improve how MaxVF is computed while taking into account that MaxVF should not be larger than the loop's trip count.

Other than saving on compile-time by pruning the possible MaxVF candidates, this patch fixes pr34438 which exposed the following flow:
1. Short trip count identified -> Don't bail out, set OptForSize:=True to avoid tail-loop and runtime checks.
2. Compute MaxVF returned 16 on a target supporting AVX512.
3. OptForSize -> choose VF:=MaxVF.
4. Bail out because TripCount = 8, VF = 16, TripCount % VF !=0 means we need a tail loop.

With this patch step 2. will choose MaxVF=8 based on TripCount.

Reviewers: Ayal, dorit, mkuper, hfinkel

Reviewed By: hfinkel

Subscribers: hfinkel, llvm-commits

Differential Revision: https://reviews.llvm.org/D37425

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312472 91177308-0d34-0410-b5e6-96231b3b80d8

2017-09-04 08:35:13 +00:00

..

CMakeLists.txt

[LV] Fix PR34248 - recommit D32871 after revert r311304

2017-08-27 12:55:46 +00:00

LLVMBuild.txt

Update libdeps since TLI was moved from Target to Analysis in r226078.

2015-01-15 05:21:00 +00:00

LoadStoreVectorizer.cpp

[KnownBits] Add bit counting methods to KnownBits struct and use them where possible

2017-05-12 17:20:30 +00:00

LoopVectorize.cpp

LoopVectorize: MaxVF should not be larger than the loop trip count

2017-09-04 08:35:13 +00:00

SLPVectorizer.cpp

[Analysis, Transforms] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).

2017-09-01 21:37:29 +00:00

Vectorize.cpp

Remove the BBVectorize pass.

2017-06-30 07:09:08 +00:00

VPlan.cpp

[LV] Fix PR34248 - recommit D32871 after revert r311304

2017-08-27 12:55:46 +00:00

VPlan.h

[LV] Fix PR34248 - recommit D32871 after revert r311304

2017-08-27 12:55:46 +00:00