VPBlendRecipe does not use the first mask operand. Removing it allows
VPlan-based DCE to remove unused mask computations.
This also fixes#87410, where unused Not VPInstructions are considered
having only their first lane demanded, but some of their operands
providing a vector value due to other users.
Fixes https://github.com/llvm/llvm-project/issues/87410
PR: https://github.com/llvm/llvm-project/pull/87770
Update createScalarIVSteps to take an insert point as parameter. This
ensures that the inserted scalar steps are in the same order as the
recipes they replace (vs in reverse order as currently). This helps to
reduce the diff for follow-up changes.
At the moment, block and edge masks are created on demand, which means
that they are inserted at the point where they are demanded and then
cached. It is possible that the mask for a block is looked up later at a
point that's not dominated by the point where the mask has been
inserted.
To avoid this, create masks up front on entry to the corresponding basic
block and leave it to VPlan simplification to remove unneeded masks.
Note that we need to create masks for all blocks, if any of the blocks
in the loop needs predication, as computing the mask of a block depends
on the masks of its predecessor.
Needed for #76090.
https://github.com/llvm/llvm-project/pull/76635
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
Check lines for some of these tests were regenerated. The difference
is that with opaque pointers SCEVExpander always emits i8 GEPs,
making the address calculation explicit. This is a known problem
that will be solved long term by making all address calculations
explicit.
All information is already available in VPlan. Note that there are some
test changes, because we now can correctly look through instructions
like truncates to analyze the actual users.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D123541
Update a bunch of loop-vectorize regression tests to use the new PM
syntax (opt -passes=loop-vectorize) instead of the deprecated legacy
PM syntax (opt -loop-vectorize).
This patch is a follow-up to D115953. It updates optimizeInductions
to also introduce new VPScalarIVStepsRecipes if an IV has both vector
and scalar uses.
It updates all uses that only need scalar values to use the newly
created recipe for the scalar steps.
This completes untangling of VPWidenIntOrFpInductionRecipe
code-generation. Now the recipe *only* creates the widened vector
values, as it says on the tin.
The code to genereate IR has been moved directly to
VPWidenIntOrFpInductionRecipe::execute.
Note that the recipe has been updated to hold a reference to
ScalarEvolution, which is needed to expand the step, until we can place
the corresponding SCEV expansion in the pre-header.
Depends on D120827.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D120828
This patch adds a new transform to remove dead recipes. For now, it only
removes dead recipes in the header, to keep the number tests that require
updating manageable. Future patches will extend this to remove dead
recipes across the whole plan.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D118051
This patch fixes PR52111. The problem is that LV propagates poison-generating flags (`nuw`/`nsw`, `exact`
and `inbounds`) in instructions that contribute to the address computation of widen loads/stores that are
guarded by a condition. It may happen that when the code is vectorized and the control flow within the loop
is linearized, these flags may lead to generating a poison value that is effectively used as the base address
of the widen load/store. The fix drops all the integer poison-generating flags from instructions that
contribute to the address computation of a widen load/store whose original instruction was in a basic block
that needed predication and is not predicated after vectorization.
Reviewed By: fhahn, spatel, nlopes
Differential Revision: https://reviews.llvm.org/D111846
This patch marks the induction increment of the main induction variable
of the vector loop as NUW when not folding the tail.
If the tail is not folded, we know that End - Start >= Step (either
statically or through the minimum iteration checks). We also know that both
Start % Step == 0 and End % Step == 0. We exit the vector loop if %IV +
%Step == %End. Hence we must exit the loop before %IV + %Step unsigned
overflows and we can mark the induction increment as NUW.
This should make SCEV return more precise bounds for the created vector
loops, used by later optimizations, like late unrolling.
At the moment quite a few tests still need to be updated, but before
doing so I'd like to get initial feedback to make sure I am not missing
anything.
Note that this could probably be further improved by using information
from the original IV.
Attempt of modeling of the assumption in Alive2:
https://alive2.llvm.org/ce/z/H_DL_g
Part of a set of fixes required for PR50412.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D103255
This reverts the revert commit 437f0bbcd509d0ed71b91ec1f86f48c2f4aae980.
It adds a new toVPRecipeResult, which forces VPRecipeOrVPValueTy to be
constructed with a VPRecipeBase *. This should address ambiguous
constructor issues for recipe sub-types that also inherit from VPValue.
This reverts commit 4efa097eb4c87d7ffe09a95a5b4ff372bdddda85, because
some the compilers used for some bots do not support automatic
conversions to PointerUnion.
Generalize the return value of tryToCreateWidenRecipe to return either a
newly create recipe or an existing VPValue. Use this to avoid creating
unnecessary VPBlendRecipes.
Fixes PR44800.
