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llvm-mirror/lib/Transforms/Vectorize
David Sherwood 9740b5c5ef [LoopVectorize] Improve vectorisation of some intrinsics by treating them as uniform
This patch adds more instructions to the Uniforms list, for example certain
intrinsics that are uniform by definition or whose operands are loop invariant.
This list includes:

  1. The intrinsics 'experimental.noalias.scope.decl' and 'sideeffect', which
  are always uniform by definition.
  2. If intrinsics 'lifetime.start', 'lifetime.end' and 'assume' have
  loop invariant input operands then these are also uniform too.

Also, in VPRecipeBuilder::handleReplication we check if an instruction is
uniform based purely on whether or not the instruction lives in the Uniforms
list. However, there are certain cases where calls to some intrinsics can
be effectively treated as uniform too. Therefore, we now also treat the
following cases as uniform for scalable vectors:

  1. If the 'assume' intrinsic's operand is not loop invariant, then we
  are free to treat this as uniform anyway since it's only a performance
  hint. We will get the benefit for the first lane.
  2. When the input pointers for 'lifetime.start' and 'lifetime.end' are loop
  variant then for scalable vectors we assume these still ultimately come
  from the broadcast of an alloca. We do not support scalable vectorisation
  of loops containing alloca instructions, hence the alloca itself would
  be invariant. If the pointer does not come from an alloca then the
  intrinsic itself has no effect.

I have updated the assume test for fixed width, since we now treat it
as uniform:

  Transforms/LoopVectorize/assume.ll

I've also added new scalable vectorisation tests for other intriniscs:

  Transforms/LoopVectorize/scalable-assume.ll
  Transforms/LoopVectorize/scalable-lifetime.ll
  Transforms/LoopVectorize/scalable-noalias-scope-decl.ll

Differential Revision: https://reviews.llvm.org/D107284

(cherry picked from commit 3fd96e1b2e129b981f1bc1be2615486187e74687)
2021-08-16 11:32:41 -07:00
..
CMakeLists.txt
LoadStoreVectorizer.cpp [LoadStoreVectorizer] Support opaque pointers 2021-06-27 15:42:16 +02:00
LoopVectorizationLegality.cpp [LV] Enable vectorization of multiple exit loops w/computable exit counts 2021-07-15 08:53:51 -07:00
LoopVectorizationPlanner.h [LoopVectorize] Fix strict reductions where VF = 1 2021-06-28 11:27:10 +01:00
LoopVectorize.cpp [LoopVectorize] Improve vectorisation of some intrinsics by treating them as uniform 2021-08-16 11:32:41 -07:00
SLPVectorizer.cpp [SLP]Fix costs calculations. 2021-07-26 07:14:03 -07:00
VectorCombine.cpp [IR] Deprecate GetElementPtrInst::CreateInBounds without element type 2021-07-04 16:49:30 +02:00
Vectorize.cpp
VPlan.cpp Recommit "[VPlan] Add recipe for first-order rec phis, make splicing explicit." 2021-07-26 15:50:30 +01:00
VPlan.h Recommit "[VPlan] Add recipe for first-order rec phis, make splicing explicit." 2021-07-26 15:50:30 +01:00
VPlanDominatorTree.h
VPlanHCFGBuilder.cpp
VPlanHCFGBuilder.h
VPlanLoopInfo.h
VPlanPredicator.cpp
VPlanPredicator.h
VPlanSLP.cpp VPlanSLP.cpp - tidy implicit header dependencies. NFCI. 2021-06-13 12:37:17 +01:00
VPlanTransforms.cpp Recommit "[VPlan] Add recipe for first-order rec phis, make splicing explicit." 2021-07-26 15:50:30 +01:00
VPlanTransforms.h [VPlan] Merge predicated-triangle regions, after sinking. 2021-06-28 11:10:38 +01:00
VPlanValue.h Recommit "[VPlan] Add recipe for first-order rec phis, make splicing explicit." 2021-07-26 15:50:30 +01:00
VPlanVerifier.cpp
VPlanVerifier.h
VPRecipeBuilder.h [VPlan] Track both incoming values for first-order recurrence phis. 2021-06-27 14:29:35 +01:00