Commit Graph

27868 Commits

Author SHA1 Message Date
Johannes Doerfert 8cb7d71355 [OpenMP][FIX] Add missing `)` to remark 2021-07-10 18:40:32 -05:00
Johannes Doerfert d9659bf6a0 [OpenMP] Create custom state machines for generic target regions
In the spirit of TRegions [0], this patch creates a custom state
machine for a generic target region based on the potentially called
parallel regions.

The code analysis is done interprocedurally via an abstract attribute
(AAKernelInfo). All outermost parallel regions are collected and we
check if there might be unknown outermost parallel regions for which
we need an indirect call. Other AAKernelInfo extensions are expected.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

Differential Revision: https://reviews.llvm.org/D101977
2021-07-10 17:57:08 -05:00
Johannes Doerfert e2cfbfcc0c [OpenMP] Unified entry point for SPMD & generic kernels in the device RTL
In the spirit of TRegions [0], this patch provides a simpler and uniform
interface for a kernel to set up the device runtime. The OMPIRBuilder is
used for reuse in Flang. A custom state machine will be generated in the
follow up patch.

The "surplus" threads of the "master warp" will not exit early anymore
so we need to use non-aligned barriers. The new runtime will not have an
extra warp but also require these non-aligned barriers.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

This was in parts extracted from D59319.

Reviewed By: ABataev, JonChesterfield

Differential Revision: https://reviews.llvm.org/D101976
2021-07-10 17:53:56 -05:00
Johannes Doerfert 4761d29633 [Attributor][FIX] Sanitize queries to LVI and ScalarEvolution
When we talk to outside analyse, e.g., LVI and ScalarEvolution, we need
to be careful with the query. The particular error occurred because we
folded a PHI node before the LVI query but the context location was now
not dominated by the value anymore. This is not supported by LVI so we
have to filter these situations before we query the outside analyses.
2021-07-10 16:45:19 -05:00
Johannes Doerfert c1d53a316d [Attributor] Look through selects in genericValueTraversal
If we can simplify the select condition we can avoid one value in the
traversal.

Differential Revision: https://reviews.llvm.org/D103861
2021-07-10 16:44:05 -05:00
Johannes Doerfert c1c1fe9385 [Attributor] Reorganize AAHeapToStack
In order to simplify future extensions, e.g., the merge of
AAHeapToShared in to AAHeapToStack, we reorganize AAHeapToStack and the
state we keep for each malloc-like call. The result is also less
confusing as we only track malloc-like calls, not all calls. Further, we
only perform the updates necessary for a malloc-like to argue it can go
to the stack, e.g., we won't check all uses if we moved on to the
"must-be-freed" argument.

This patch also uses Attributor helps to simplify the allocated size,
alignment, and the potentially freed objects.

Overall, this is mostly a reorganization and only the use of the
optimistic helpers should change (=improve) the capabilities a bit.

Differential Revision: https://reviews.llvm.org/D104993
2021-07-10 16:32:24 -05:00
Johannes Doerfert dbb3a65f5b [Attributor][FIX] Do not replace a value with a non-dominating instruction
We have to be careful when we replace values to not use a non-dominating
instruction. It makes sense that simplification offers those as
"simplified values" but we can't manifest them in the IR without PHI
nodes. In the future we should consider potentially adding those PHI
nodes.
2021-07-10 16:09:30 -05:00
Johannes Doerfert 5ef18e2421 [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 15:52:36 -05:00
Johannes Doerfert 0aab13aaf9 [Attributor] Introduce an optimistic getUnderlyingObjects helper
As the `llvm::getUnderlyingObjects` helper, the optimistic version
collects objects that might be the base of a given pointer. In contrast
to the llvm variant, the optimistic one will use assumed information,
e.g., about select conditions or dead blocks, to provide a more precise
result.

Differential Revision: https://reviews.llvm.org/D103859
2021-07-10 15:47:30 -05:00
Johannes Doerfert 5b12cf3e65 [Attributor][FIX] Traverse uses even if a value is assumed constant
Not all attributes are able to handle the interprocedural step and
follow the uses into a call site. Let them be able to combine call site
uses instead. This might result in some unused values/arguments being
leftover but it removes problems where we misused "is dead" even though
it was actually "is simplified/replaced".

We explicitly check for dead values due to constant propagation in
`AAIsDeadValueImpl::areAllUsesAssumedDead` instead.

Differential Revision: https://reviews.llvm.org/D103858
2021-07-10 15:47:20 -05:00
Nico Weber d3e7491333 Revert Attributor patch series
Broke check-clang, see https://reviews.llvm.org/D102307#2869065
Ran `git revert -n ebbe149a6f08535ede848a531a601ae6591cfbc5..269416d41908bb670f67af689155d5ab8eea689a`
2021-07-10 16:15:55 -04:00
Johannes Doerfert 269416d419 [Attributor][NFCI] Add UsedAssumedInformation to more interfaces
As with other Attributor interfaces we often want to know if assumed
information was used to answer a query. This is important if only
known information is allowed or if known information can lead to an
early fixpoint. The users have been adjusted but none of them utilizes
the new information yet.
2021-07-10 12:32:51 -05:00
Johannes Doerfert d39179d7fa [OpenMP] Detect SPMD compatible kernels and execute them as such
In the spirit of TRegions [0], this patch analyzes a kernel and tracks
if it can be executed in SPMD-mode. If so, we flip the arguments of
the __kmpc_target_init and deinit call to enable the mode. We also
update the `<kernel>_exec_mode` flag to indicate to the runtime we
changed the mode to SPMD.

The code analysis is done interprocedurally by extending the
AAKernelInfo abstract attribute to track SPMD compatibility as well.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

Differential Revision: https://reviews.llvm.org/D102307
2021-07-10 12:32:51 -05:00
Johannes Doerfert 966342790e [Attributor][FIX] Sanitize queries to LVI and ScalarEvolution
When we talk to outside analyse, e.g., LVI and ScalarEvolution, we need
to be careful with the query. The particular error occurred because we
folded a PHI node before the LVI query but the context location was now
not dominated by the value anymore. This is not supported by LVI so we
have to filter these situations before we query the outside analyses.
2021-07-10 12:32:51 -05:00
Johannes Doerfert ae08df87df [Attributor][FIX] Do not replace a value with a non-dominating instruction
We have to be careful when we replace values to not use a non-dominating
instruction. It makes sense that simplification offers those as
"simplified values" but we can't manifest them in the IR without PHI
nodes. In the future we should consider potentially adding those PHI
nodes.
2021-07-10 12:32:50 -05:00
Johannes Doerfert f0628c6ff7 [OpenMP] Create custom state machines for generic target regions
In the spirit of TRegions [0], this patch creates a custom state
machine for a generic target region based on the potentially called
parallel regions.

The code analysis is done interprocedurally via an abstract attribute
(AAKernelInfo). All outermost parallel regions are collected and we
check if there might be unknown outermost parallel regions for which
we need an indirect call. Other AAKernelInfo extensions are expected.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

Differential Revision: https://reviews.llvm.org/D101977
2021-07-10 12:32:50 -05:00
Johannes Doerfert 1d5711c3ee [OpenMP] Unified entry point for SPMD & generic kernels in the device RTL
In the spirit of TRegions [0], this patch provides a simpler and uniform
interface for a kernel to set up the device runtime. The OMPIRBuilder is
used for reuse in Flang. A custom state machine will be generated in the
follow up patch.

The "surplus" threads of the "master warp" will not exit early anymore
so we need to use non-aligned barriers. The new runtime will not have an
extra warp but also require these non-aligned barriers.

[0] https://link.springer.com/chapter/10.1007/978-3-030-28596-8_11

This was in parts extracted from D59319.

Reviewed By: ABataev, JonChesterfield

Differential Revision: https://reviews.llvm.org/D101976
2021-07-10 12:32:50 -05:00
Johannes Doerfert 5003ba2542 [Attributor] Look through selects in genericValueTraversal
If we can simplify the select condition we can avoid one value in the
traversal.

Differential Revision: https://reviews.llvm.org/D103861
2021-07-10 12:32:50 -05:00
Johannes Doerfert 1eb31d6de3 [Attributor] Reorganize AAHeapToStack
In order to simplify future extensions, e.g., the merge of
AAHeapToShared in to AAHeapToStack, we reorganize AAHeapToStack and the
state we keep for each malloc-like call. The result is also less
confusing as we only track malloc-like calls, not all calls. Further, we
only perform the updates necessary for a malloc-like to argue it can go
to the stack, e.g., we won't check all uses if we moved on to the
"must-be-freed" argument.

This patch also uses Attributor helps to simplify the allocated size,
alignment, and the potentially freed objects.

Overall, this is mostly a reorganization and only the use of the
optimistic helpers should change (=improve) the capabilities a bit.

Differential Revision: https://reviews.llvm.org/D104993
2021-07-10 12:32:50 -05:00
Johannes Doerfert 374e573cfc [Attributor] Use AAValueSimplify to simplify returned values
We should use AAValueSimplify for all value simplification, however
there was some leftover logic that predates AAValueSimplify in
AAReturnedValues. This remove the AAReturnedValues part and provides a
replacement by making AAValueSimplifyReturned strong enough to handle
all previously covered cases. Further, this improve
AAValueSimplifyCallSiteReturned to handle returned arguments.

AAReturnedValues is now much easier and the collected returned
values/instructions are now from the associated function only, making it
much more sane. We also do not have the brittle logic anymore that looks
for unresolved calls. Instead, we use AAValueSimplify to handle
recursion.

Useful code has been split into helper functions, e.g., an Attributor
interface to get a simplified value.

Differential Revision: https://reviews.llvm.org/D103860
2021-07-10 12:32:50 -05:00
Johannes Doerfert 93a279a67d [Attributor] Introduce an optimistic getUnderlyingObjects helper
As the `llvm::getUnderlyingObjects` helper, the optimistic version
collects objects that might be the base of a given pointer. In contrast
to the llvm variant, the optimistic one will use assumed information,
e.g., about select conditions or dead blocks, to provide a more precise
result.

Differential Revision: https://reviews.llvm.org/D103859
2021-07-10 12:32:49 -05:00
Johannes Doerfert be5d46e9bb [Attributor][FIX] Traverse uses even if a value is assumed constant
Not all attributes are able to handle the interprocedural step and
follow the uses into a call site. Let them be able to combine call site
uses instead. This might result in some unused values/arguments being
leftover but it removes problems where we misused "is dead" even though
it was actually "is simplified/replaced".

We explicitly check for dead values due to constant propagation in
`AAIsDeadValueImpl::areAllUsesAssumedDead` instead.

Differential Revision: https://reviews.llvm.org/D103858
2021-07-10 12:32:49 -05:00
Sander de Smalen 239fcda268 [LV] NFCI: Do cost comparison on InstructionCost directly.
Instead of performing the isMoreProfitable() operation on
InstructionCost::CostTy the operation is performed on InstructionCost
directly, so that it can handle the case where one of the costs is
Invalid.

This patch also changes the CostTy to be int64_t, so that the type is
wide enough to deal with multiplications with e.g. `unsigned MaxTripCount`.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D105113
2021-07-10 11:57:16 +01:00
Eli Friedman 9c4baf5101 [ScalarEvolution] Strictly enforce pointer/int type rules.
Rules:

1. SCEVUnknown is a pointer if and only if the LLVM IR value is a
   pointer.
2. SCEVPtrToInt is never a pointer.
3. If any other SCEV expression has no pointer operands, the result is
   an integer.
4. If a SCEVAddExpr has exactly one pointer operand, the result is a
   pointer.
5. If a SCEVAddRecExpr's first operand is a pointer, and it has no other
   pointer operands, the result is a pointer.
6. If every operand of a SCEVMinMaxExpr is a pointer, the result is a
   pointer.
7. Otherwise, the SCEV expression is invalid.

I'm not sure how useful rule 6 is in practice.  If we exclude it, we can
guarantee that ScalarEvolution::getPointerBase always returns a
SCEVUnknown, which might be a helpful property. Anyway, I'll leave that
for a followup.

This is basically mop-up at this point; all the changes with significant
functional effects have landed.  Some of the remaining changes could be
split off, but I don't see much point.

Differential Revision: https://reviews.llvm.org/D105510
2021-07-09 17:29:26 -07:00
Valery N Dmitriev 8e9216fe87 [SLP] Do not make an attempt to match reduction on already erased instruction.
Differential Revision: https://reviews.llvm.org/D105752
2021-07-09 17:13:15 -07:00
Kazu Hirata 49d66d9f9f [AFDO] Merge function attributes after inlining
This patch teaches the sample profile loader to merge function
attributes after inlining functions.

Without this patch, the compiler could inline a function requiring the
512-bit vector width into its caller without merging function
attributes, triggering a failure during instruction selection.

Differential Revision: https://reviews.llvm.org/D105729
2021-07-09 16:47:12 -07:00
Sanjay Patel c2b7f09d8c [SLP] make invalid operand explicit for extra arg in reduction matching; NFC
This makes it clearer when we have encountered the extra arg.
Also, we may need to adjust the way the operand iteration
works when handling logical and/or.
2021-07-09 15:32:12 -04:00
Varun Gandhi 92dcb1d2db [Clang] Introduce Swift async calling convention.
This change is intended as initial setup. The plan is to add
more semantic checks later. I plan to update the documentation
as more semantic checks are added (instead of documenting the
details up front). Most of the code closely mirrors that for
the Swift calling convention. Three places are marked as
[FIXME: swiftasynccc]; those will be addressed once the
corresponding convention is introduced in LLVM.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D95561
2021-07-09 11:50:10 -07:00
Arthur Eubanks 9a7afae492 [OpaquePtr][InferAddrSpace] Use PointerType::getWithSamePointeeType() 2021-07-09 10:29:08 -07:00
Arthur Eubanks 4e6013250d [NFC][OpaquePtr] Use GlobalValue::getValueType() more
Instead of getType()->getElementType().
2021-07-09 09:55:41 -07:00
Sanjay Patel 486992f958 [SLP] improve code comments; NFC
This likely started out only supporint binops,
but now we handle min/max using cmp+sel, and
we may extend to handle bool logic in the form
of select.
2021-07-09 12:49:54 -04:00
Sanjay Patel 544f2711bb [SLP] make checks for cmp+select min/max more explicit
This is NFC-intended currently (so no test diffs). The motivation
is to eventually allow matching for poison-safe logical-and and
logical-or (these are in the form of a select-of-bools).
( https://llvm.org/PR41312 )

Those patterns will not have all of the same constraints as min/max
in the form of cmp+sel. We may also end up removing the cmp+sel
min/max matching entirely (if we canonicalize to intrinsics), so
this will make that step easier.
2021-07-09 12:43:43 -04:00
Arthur Eubanks e4f66a1055 [OpaquePointers][CallPromotion] Don't look at pointee type for byval
byval's type parameter is now always required.
2021-07-09 09:34:05 -07:00
Nico Weber 97c675d3d4 Revert "Revert "Temporarily do not drop volatile stores before unreachable""
This reverts commit 52aeacfbf5.
There isn't full agreement on a path forward yet, but there is agreement that
this shouldn't land as-is.  See discussion on https://reviews.llvm.org/D105338

Also reverts unreviewed "[clang] Improve `-Wnull-dereference` diag to be more in-line with reality"
This reverts commit f4877c78c0.

And all the related changes to tests:
This reverts commit 9a0152799f.
This reverts commit 3f7c9cc274.
This reverts commit 329f8197ef.
This reverts commit aa9f58cc2c.
This reverts commit 2df37d5ddd.
This reverts commit a72a441812.
2021-07-09 11:44:34 -04:00
Kevin P. Neal 52900486a1 [FPEnv][InstSimplify] Constrained FP support for NaN
Currently InstructionSimplify.cpp knows how to simplify floating point
instructions that have a NaN operand. It does not know how to handle the
matching constrained FP intrinsic.

This patch teaches it how to simplify so long as the exception handling
is not "fpexcept.strict".

Differential Revision: https://reviews.llvm.org/D103169
2021-07-09 11:26:28 -04:00
Roman Lebedev 4e332cd41a
Revert "Transform memset + malloc --> calloc (PR25892)"
It broke `check-msan`, see e.g. https://lab.llvm.org/buildbot/#/builders/18/builds/1934

This reverts commit 375694a07b.
2021-07-09 16:26:48 +03:00
Roman Lebedev 52aeacfbf5
Revert "Temporarily do not drop volatile stores before unreachable"
This reverts commit 4e413e1621,
which landed almost 10 months ago under premise that the original behavior
didn't match reality and was breaking users, even though it was correct as per
the LangRef. But the LangRef change still hasn't appeared, which might suggest
that the affected parties aren't really worried about this problem.

Please refer to discussion in:
* https://reviews.llvm.org/D87399 (`Revert "[InstCombine] erase instructions leading up to unreachable"`)
* https://reviews.llvm.org/D53184 (`[LangRef] Clarify semantics of volatile operations.`)
* https://reviews.llvm.org/D87149 (`[InstCombine] erase instructions leading up to unreachable`)

clang has `-Wnull-dereference` which will diagnose the obvious cases
of null dereference, it was adjusted in f4877c78c0,
but it will only catch the cases where the pointer is a null literal,
it will not catch the cases where an arbitrary store is expected to trap.

Differential Revision: https://reviews.llvm.org/D105338
2021-07-09 14:16:54 +03:00
Max Kazantsev 9c5e65691e [LoopDeletion] Handle switch in proving that loop exits on first iteration
Added check for switch-terminated blocks in loops.
Now if a block is terminated with a switch, we try to find out which of the
cases is taken on 1st iteration and mark corresponding edge from the block
to the case successor as live.

Patch by Dmitry Makogon!

Differential Revision: https://reviews.llvm.org/D105688
Reviewed By: nikic, mkazantsev
2021-07-09 18:03:34 +07:00
David Green 38c9a4068d [TTI] Remove IsPairwiseForm from getArithmeticReductionCost
This patch removes the IsPairwiseForm flag from the Reduction Cost TTI
hooks, along with some accompanying code for pattern matching reductions
from trees starting at extract elements. IsPairWise is now assumed to be
false, which was the predominant way that the value was used from both
the Loop and SLP vectorizers. Since the adjustments such as D93860, the
SLP vectorizer has not relied upon this distinction between paiwise and
non-pairwise reductions.

This also removes some code that was detecting reductions trees starting
from extract elements inside the costmodel. This case was
double-counting costs though, adding the individual costs on the
individual instruction _and_ the total cost of the reduction. Removing
it changes the costs in llvm/test/Analysis/CostModel/X86/reduction.ll to
not double count. The cost of reduction intrinsics is still tested
through the various tests in
llvm/test/Analysis/CostModel/X86/reduce-xyz.ll.

Differential Revision: https://reviews.llvm.org/D105484
2021-07-09 11:51:16 +01:00
Dawid Jurczak 375694a07b Transform memset + malloc --> calloc (PR25892)
After this change DSE can eliminate malloc + memset and emit calloc.
It's https://reviews.llvm.org/D101440 follow-up.

Differential Revision: https://reviews.llvm.org/D103009
2021-07-09 11:01:12 +02:00
Bjorn Pettersson 472462c472 [NewPM] Consistently use 'simplifycfg' rather than 'simplify-cfg'
There was an alias between 'simplifycfg' and 'simplify-cfg' in the
PassRegistry. That was the original reason for this patch, which
effectively removes the alias.

This patch also replaces all occurrances of 'simplify-cfg'
by 'simplifycfg'. Reason for choosing that form for the name is
that it matches the DEBUG_TYPE for the pass, and the legacy PM name
and also how it is spelled out in other passes such as
'loop-simplifycfg', and in other options such as
'simplifycfg-merge-cond-stores'.

I for some reason the name should be changed to 'simplify-cfg' in
the future, then I think such a renaming should be more widely done
and not only impacting the PassRegistry.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D105627
2021-07-09 09:47:03 +02:00
Reshabh Sharma 2e194dec60 [ASan][AMDGPU] Make shadow offset match X86 on Linux
This patch explicitly sets the shadow offset for
AMDGPU to match that of X86 on Linux.

Reviewed By: vitalybuka

https://reviews.llvm.org/D105282
2021-07-09 07:48:03 +05:30
Alexey Bataev 8af69975af [InstCombine][NFC]Use only `replaceInstUsesWith`, NFC. 2021-07-08 13:58:30 -07:00
David Blaikie 1def2579e1 PR51018: Remove explicit conversions from SmallString to StringRef to future-proof against C++23
C++23 will make these conversions ambiguous - so fix them to make the
codebase forward-compatible with C++23 (& a follow-up change I've made
will make this ambiguous/invalid even in <C++23 so we don't regress
this & it generally improves the code anyway)
2021-07-08 13:37:57 -07:00
Vitaly Buka 915e07605c [msan] Handle funnel shifts
Fixes https://bugs.llvm.org/show_bug.cgi?id=50840

Differential Revision: https://reviews.llvm.org/D105387
2021-07-08 12:49:49 -07:00
Alexey Bataev c574d2fbac [SLP]Improve vectorization of stores.
Patch tries to improve the vectorization of stores. Originally, we just
check the type and the base pointer of the store.
Patch adds some extra checks to avoid non-profitable vectorization
cases. It includes analysis of the scalar values to be stored and
triggers the vectorization attempt only if the scalar values have
same/alt opcode and are from same basic block, i.e. we don't end up
immediately with the gather node, which is not profitable.
This also improves compile time by filtering out non-profitable cases.

Part of D57059.

Differential Revision: https://reviews.llvm.org/D104122
2021-07-08 12:35:39 -07:00
Alexey Bataev 0d74fd3fdf [SLP][COST][X86]Improve cost model for masked gather.
Revived D101297 in its original form + added some changes in X86
legalization cehcking for masked gathers.

This solution is the most stable and the most correct one. We have to
check the legality before trying to build the masked gather in SLP.
Without this check we have incorrect cost (for SLP) in case if the masked gather
is not legal/slower than the gather. And we're missing some
vectorization opportunities.

This can be fixed in the cost model, but in this case we need to add
special checks for the cost of GEPs for ScatterVectorize node, add
special check for small trees, etc., i.e. there are a lot of corner
cases here and there, which insrease code base and make it harder to
maintain the code.

> Can't we rely on cost model to deal with this? This can be profitable for futher vectorization, when we can start from such gather loads as seed.

The question from D101297. Actually, no, it can't. Actually, simple
gather may give us better result, especially after we started
vectorization of insertelements. Plus, like I said before, the cost for
non-legal masked gathers leads to missed vectorization opportunities.

Differential Revision: https://reviews.llvm.org/D105042
2021-07-08 11:53:30 -07:00
Alexey Bataev b5113bff46 [Instcombine]Transform reduction+(sext/zext(<n x i1>) to <n x im>) to [-]zext/trunc(ctpop(bitcast <n x i1> to in)) to im.
Some of the SPEC tests end up with reduction+(sext/zext(<n x i1>) to <n x im>) pattern, which can be transformed to [-]zext/trunc(ctpop(bitcast <n x i1> to in)) to im.
Also, reduction+(<n x i1>) can be transformed to ctpop(bitcast <n x i1> to in) & 1 != 0.

Differential Revision: https://reviews.llvm.org/D105587
2021-07-08 07:56:41 -07:00
Michael Liao 4e5d9c8803 [Internalize] Preserve variables externally initialized.
- ``externally_initialized`` variables would be initialized or modified
  elsewhere. Particularly, CUDA or HIP may have host code to initialize
  or modify ``externally_initialized`` device variables, which may not
  be explicitly referenced on the device side but may still be used
  through the host side interfaces. Not preserving them triggers the
  elimination of them in the GlobalDCE and breaks the user code.

Reviewed By: yaxunl

Differential Revision: https://reviews.llvm.org/D105135
2021-07-08 10:48:19 -04:00
Nikita Popov 84c15bc018 [SCEVExpander] Support opaque pointers
This adds support for opaque pointers to expandAddToGEP() by always
generating an i8 GEP for opaque pointers. After looking at some other
cases (constexpr GEP folding, SROA GEP generation), I've come around
to the idea that we should use i8 GEPs for opaque pointers, because
the alternative would be to guess a GEP type from surrounding code,
which will not be reliable. Ultimately, i8 GEPs is where we want to
end up anyway, and opaque pointers just make that the natural choice.

There are a couple of other places in SCEVExpander that check pointer
element types, I plan to update those when I run across usable test
coverage that doesn't assert elsewhere.

Differential Revision: https://reviews.llvm.org/D105398
2021-07-07 20:47:59 +02:00