Commit Graph

8 Commits

Author SHA1 Message Date
Florian Hahn 80aa7e147e
[VPlan] Merge predicated-triangle regions, after sinking.
Sinking scalar operands into predicated-triangle regions may allow
merging regions. This patch adds a VPlan-to-VPlan transform that tries
to merge predicate-triangle regions after sinking.

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D100260
2021-06-28 11:10:38 +01:00
Joe Ellis 2c551aedcf [LoopVectorize] Fix bug where predicated loads/stores were dropped
This commit fixes a bug where the loop vectoriser fails to predicate
loads/stores when interleaving for targets that support masked
loads and stores.

Code such as:

     1  void foo(int *restrict data1, int *restrict data2)
     2  {
     3    int counter = 1024;
     4    while (counter--)
     5      if (data1[counter] > data2[counter])
     6        data1[counter] = data2[counter];
     7  }

... could previously be transformed in such a way that the predicated
store implied by:

    if (data1[counter] > data2[counter])
       data1[counter] = data2[counter];

... was lost, resulting in miscompiles.

This bug was causing some tests in llvm-test-suite to fail when built
for SVE.

Differential Revision: https://reviews.llvm.org/D99569
2021-04-22 15:05:54 +00:00
Juneyoung Lee 4a8e6ed2f7 [SLP,LV] Use poison constant vector for shufflevector/initial insertelement
This patch makes SLP and LV emit operations with initial vectors set to poison constant instead of undef.
This is a part of efforts for using poison vector instead of undef to represent "doesn't care" vector.
The goal is to make nice shufflevector optimizations valid that is currently incorrect due to the tricky interaction between undef and poison (see https://bugs.llvm.org/show_bug.cgi?id=44185 ).

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D94061
2021-01-06 11:22:50 +09:00
Roman Lebedev 5cce4aff18
[SimplifyCFG] TryToSimplifyUncondBranchFromEmptyBlock() already knows how to preserve DomTree
... so just ensure that we pass DomTreeUpdater it into it.

Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.
2020-12-17 01:03:49 +03:00
Eric Christopher cee313d288 Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
2019-04-17 04:52:47 +00:00
Eric Christopher a863435128 Temporarily Revert "Add basic loop fusion pass."
As it's causing some bot failures (and per request from kbarton).

This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.

llvm-svn: 358546
2019-04-17 02:12:23 +00:00
Gil Rapaport 848581cadb [LV] Introduce VPBlendRecipe, VPWidenMemoryInstructionRecipe
This patch is part of D38676.

The patch introduces two new Recipes to handle instructions whose vectorization
involves masking. These Recipes take VPlan-level masks in D38676, but still rely
on ILV's existing createEdgeMask(), createBlockInMask() in this patch.

VPBlendRecipe handles intra-loop phi nodes, which are vectorized as a sequence
of SELECTs. Its execute() code is refactored out of ILV::widenPHIInstruction(),
which now handles only loop-header phi nodes.

VPWidenMemoryInstructionRecipe handles load/store which are to be widened
(but are not part of an Interleave Group). In this patch it simply calls
ILV::vectorizeMemoryInstruction on execute().

Differential Revision: https://reviews.llvm.org/D39068

llvm-svn: 318149
2017-11-14 12:09:30 +00:00
Matthew Simpson 364da7e527 [LV] Scalarize operands of predicated instructions
This patch attempts to scalarize the operand expressions of predicated
instructions if they were conditionally executed in the original loop. After
scalarization, the expressions will be sunk inside the blocks created for the
predicated instructions. The transformation essentially performs
un-if-conversion on the operands.

The cost model has been updated to determine if scalarization is profitable. It
compares the cost of a vectorized instruction, assuming it will be
if-converted, to the cost of the scalarized instruction, assuming that the
instructions corresponding to each vector lane will be sunk inside a predicated
block, possibly avoiding execution. If it's more profitable to scalarize the
entire expression tree feeding the predicated instruction, the expression will
be scalarized; otherwise, it will be vectorized. We only consider the cost of
the entire expression to accurately estimate the cost of the required
insertelement and extractelement instructions.

Differential Revision: https://reviews.llvm.org/D26083

llvm-svn: 288909
2016-12-07 15:03:32 +00:00