This patch introduces a new ComputeReductionResult opcode to compute the
final reduction result in the middle block. The code from fixReduction
has been moved to ComputeReductionResult, after some earlier cleanup
changes to model parts of fixReduction explicitly elsewhere as needed.
The recipe may be broken down further in the future.
Note that the phi nodes to merge the reduction result from the trip
count check and the middle block, to be used as resume value for the
scalar remainder loop are also generated based on
ComputeReductionResult.
Once we have a VPValue for the reduction result, this can also be
modeled explicitly and moved out of the recipe.
This reverts commit e4ea0997486000b460c4875a00301b73b3c0d6a7.
The recommit fixes a reported crash by adding a missing check to make
sure the cast recipes are only introduced when vectorizing.
Test coverage added in 3cac608fbd0811b2f5c59c6e13148162ccd8543e.
Original commit message:
Update the code to create Trunc/Ext recipes directly in
adjustRecipesForReductions instead of fixing it up later in
fixReductions.
This explicitly models the required conversions and also makes sure they
are generated at the right place (instead of after the exit condition),
hence the changes in a few tests.
Update the code to create Trunc/Ext recipes directly in
adjustRecipesForReductions instead of fixing it up later in
fixReductions.
This explicitly models the required conversions and also makes sure they
are generated at the right place (instead of after the exit condition),
hence the changes in a few tests.
Split off from D150398 to avoid builder-related diff changes there.
Using IRBuilder to create ICmps simplifies the result if both operands
are constants.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D158332
Instcombine prefers this canonical form (see getPreferredVectorIndex),
as does IRBuilder when passing the index as an integer so we may as
well use the prefered form from creation.
NOTE: All test changes are mechanical with nothing else expected
beyond a change of index type from i32 to i64.
Differential Revision: https://reviews.llvm.org/D140983
At the moment LV runs LoopSimplify and reconstructs LCSSA form after
generating the main vector loop and before generating the epilogue
vector loop.
In practice, this adds a new exit block for the scalar loop because the
middle block now also branches to the original exit block of the scalar
loop. It also requires adding a new LCSSA phi in the newly created exit
block.
This complicates things when modeling exit values in VPlan, because we
would need to update the VPlan for the epilogue loop to update the newly
created LCSSA phi node.
But none of that should be necessary, as all analysis requiring
loop-simplify form is already done at this point and LCSSA form of the
original loop is not broken.
Reviewed By: bmahjour
Differential Revision: https://reviews.llvm.org/D125810
isCandidateForEpilogueVectorization will currently return false for loops
which contain reductions. This patch removes this restriction and makes
the following changes to support epilogue vectorisation with reductions:
- `fixReduction`: If fixReduction is being called during vectorisation of the
epilogue, the phi node it creates will need to additionally carry incoming
values from the middle block of the main loop.
- `createEpilogueVectorizedLoopSkeleton`: The incoming values of the phi
created by fixReduction are updated after the vec.epilog.iter.check block
is added. The phi is also moved to the preheader of the epilogue.
- `processLoop`: The start value of any VPReductionPHIRecipes are updated before
vectorising the epilogue loop. The getResumeInstr function added to the ILV
will return the resume instruction associated with the recurrence descriptor.
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D116928
