This fixes the combining of constant vector GEP operands in the
optimization of MVE gather/scatter addresses, when opaque pointers are
enabled. As opaque pointers reduce the number of bitcasts between geps,
more can be folded than before. This can cause problems if the index
types are now different between the two geps.
This fixes that by making sure each constant is scaled appropriately,
which has the effect of transforming the geps to have a scale of 1,
changing [r0, q0, uxtw #1] gathers to [r0, q0] with a larger q0. This
helps use a simpler instruction that doesn't need the extra uxtw.
Differential Revision: https://reviews.llvm.org/D127733
LLVM has the habit of turning adds with no common bits set into ors,
which means we need to detect them and treat them like adds again in the
MVE gather/scatter lowering pass.
Differential Revision: https://reviews.llvm.org/D112922
This teaches the MVE gather scatter lowering pass that SHL is
essentially the same as Mul, where we are able to optimize the
induction of a gather/scatter address by pushing them out of loops.
https://alive2.llvm.org/ce/z/wG4VyT
Differential Revision: https://reviews.llvm.org/D112920
Corollary to 1113e06821 this allows us to
match gather that dont produce a full vector width results. They use an
extended gather which is truncated back to the original type.
This parameter controls how much space is reserved for incoming
values. There are always going to be 2 incoming values in this case.
While there remove the unused std::vector right below.
Found while looking at porting this code to RISCV.
I believe this Changed flag should be initialized to false,
otherwise the if (!Changed) is always dead. This doesn't
manifest in a functional issue because the PHINode checks will
fail if nothing changed. They are identical to the earlier
checks that must have already failed to get into this else block.
While there remove an else after return to reduce indentation.
Differential Revision: https://reviews.llvm.org/D105159
As a minor adjustment to the existing lowering of offset scatters, this
extends any smaller-than-legal vectors into full vectors using a zext,
so that the truncating scatters can be used. Due to the way MVE
legalizes the vectors this should be cheap in most situations, and will
prevent the vector from being scalarized.
Differential Revision: https://reviews.llvm.org/D103704
This commit adds nodes that might not always be used, which the
expensive checks builder does not like. Reverting for now to think up a
better way of handling it.
As a minor adjustment to the existing lowering of offset scatters, this
extends any smaller-than-legal vectors into full vectors using a zext,
so that the truncating scatters can be used. Due to the way MVE
legalizes the vectors this should be cheap in most situations, and will
prevent the vector from being scalarized.
Differential Revision: https://reviews.llvm.org/D103704
A pointer will always fit into an i32, so a rq offset gather/scatter can
be used with v4i8 and v4i16 gathers, using a base of 0 and the Ptr as
the offsets. The rq gather can then correctly extend the type, allowing
us to use the gathers without falling back to scalarizing.
This patch rejigs tryCreateMaskedGatherOffset in the
MVEGatherScatterLowering pass to decompose the Ptr into Base:0 +
Offset:Ptr (with a scale of 1), if the Ptr could not be decomposed from
a GEP. v4i32 gathers will already use qi gathers, this extends that to
v4i8 and v4i16 gathers using the extending rq variants.
Differential Revision: https://reviews.llvm.org/D103674
This adjusts some of how the gather/scatter lowering pass passes around
data and where certain gathers/scatters are created from. It should not
effect code generation on its own, but allows other patches to more
clearly reason about the code.
A number of extra test cases were also added for smaller gathers/
scatters that can be extended, and some of the test comments were
updated.
Surprisingly, not all instructions are always simplified after unrolling
and before MVE gather/scatter lowering. Notably dead gather operations
can be left around which cause the gather/scatter lowering pass to crash
if there are multiple gathers, some of which are dead.
This patch ensures they are simplified before we modify anything, which
can change some of the existing tests, including making them no-longer
test what they originally tested. This uses a combination of disabling
the gather/scatter lowering pass and adjusting the test to keep them as
before.
Differential Revision: https://reviews.llvm.org/D103150
This ensures that the operands of any gather/scatter instructions that
we attempt to push out of the loop are invariant, preventing invalid IR
from being generated.
A patch following up on the introduction of pointer induction variables, adding
a preprocessing step to the address optimisation in the MVEGatherScatterLowering
pass. If the getelementpointer that is the address is itself using a
getelementpointer as base, they will be merged into one by summing up the
offsets, after checking that this will not cause an overflow (this can be
repeated recursively).
Differential Revision: https://reviews.llvm.org/D84027
Adds support to build pre-incrementing scatters.
If the increment (i.e., add instruction) that is merged into
the scatter is the loop increment, an incrementing write-back
scatter can be built, which then assumes the role of the loop
increment.
Differential Revision: https://reviews.llvm.org/D79859
Enables the MVEGatherScatterLowering pass to build
pre-incrementing gathers. Incrementing writeback gathers
are built when it is possible to replace the loop increment
instruction.
Differential Revision: https://reviews.llvm.org/D76786
Fix for the address optimization for gathers and scatters which would in
some complex cases push out instructions not to the vector loop preheader,
but to other locations as well which lead to a scrambled order and the
compilation failing.
This patch ensures that said instructions are always pushed to the end
of the vector loop preheader.
Differential Revision: https://reviews.llvm.org/D78293
Summary:
Remove usages of asserting vector getters in Type in preparation for the
VectorType refactor. The existence of these functions complicates the
refactor while adding little value.
Reviewers: grosbach, efriedma, sdesmalen
Reviewed By: efriedma
Subscribers: hiraditya, dmgreen, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77271
This patch adds an analysis of the offset addresses used by gathers
and scatters to the MVEGatherScatterLowering pass to find
multiplications and additions that are loop invariant and thus can
be moved into the loop preheader, avoiding to execute them each time.
Differential Revision: https://reviews.llvm.org/D76681
The MVE gather instructions smaller than 32bits zext extend the values
in the offset register, as opposed to sign extending them. We need to
make sure that the code that we select from is suitably extended, which
this patch attempts to fix by tightening up the offset checks.
Differential Revision: https://reviews.llvm.org/D75361
Extends the gather/scatter pass in MVEGatherScatterLowering.cpp to
enable the transformation of masked scatters into calls to MVE's masked
scatter intrinsic.
Differential Revision: https://reviews.llvm.org/D72856
Enables the masked gather pass to create a masked
gather loading from a base and vector of offsets.
This also enables v8i16 and v16i8 gather loads.
Differential Revision: https://reviews.llvm.org/D72330
Fangrui Song