llvm-project/llvm/lib/Transforms
Hal Finkel 293a41d14f BBVectorize: Better use of TTI->getShuffleCost
When flipping the pair of subvectors that form a vector, if the
vector length is 2, we can use the SK_Reverse shuffle kind to get
more-accurate cost information. Also we can use the SK_ExtractSubvector
shuffle kind to get accurate subvector extraction costs.

The current cost model implementations don't yet seem complex enough
for this to make a difference (thus, there are no test cases with this
commit), but it should help in future.

Depending on how the various targets optimize and combine shuffles in
practice, we might be able to get more-accurate costs by combining the
costs of multiple shuffle kinds. For example, the cost of flipping the
subvector pairs could be modeled as two extractions and two subvector
insertions. These changes, however, should probably be motivated
by specific test cases.

llvm-svn: 173621
2013-01-27 20:07:01 +00:00
..
Hello Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
IPO Use the AttributeSet instead of AttributeWithIndex. 2013-01-27 01:57:28 +00:00
InstCombine Use the AttributeSet instead of AttributeWithIndex. 2013-01-27 02:08:22 +00:00
Instrumentation [msan] A comment on ICmp handling logic. 2013-01-25 15:35:29 +00:00
Scalar Renamed function IsPotentialUse to IsPotentialRetainableObjPtr. 2013-01-27 06:19:48 +00:00
Utils Re-revert r173342, without losing the compile time improvements, flat 2013-01-27 06:42:03 +00:00
Vectorize BBVectorize: Better use of TTI->getShuffleCost 2013-01-27 20:07:01 +00:00
CMakeLists.txt Add a basic-block autovectorization pass. 2012-02-01 03:51:43 +00:00
LLVMBuild.txt Add a basic-block autovectorization pass. 2012-02-01 03:51:43 +00:00
Makefile Add a basic-block autovectorization pass. 2012-02-01 03:51:43 +00:00