Commit Graph

27587 Commits

Author SHA1 Message Date
Eric Christopher add710eb23 Temporarily Revert "[StackMaps] Be explicit about label formation [NFC]"
as it broke the aarch64 build.

This reverts commit bc7595d934.
2019-12-19 12:52:40 -08:00
Philip Reames bc7595d934 [StackMaps] Be explicit about label formation [NFC]
For auto-padding assembler support, we'll need to bundle the label with the instructions (nops or call sequences) so that they don't get separated.  This just rearranges the code to make the upcoming change more obvious.
2019-12-19 12:38:44 -08:00
Philip Reames cf6aafa47c [FaultMaps] Make label formation a bit more explicit [NFC]
This is in advance of assembler padding directives support where we'll need to bundle the label w/the corresponding faulting instruction to avoid padding being inserted between.
2019-12-19 12:38:44 -08:00
Craig Topper e6e23a24be [LegalizeDAG] Add return to the strict node handling in PromoteLegalINT_TO_FP to prevent an invalid strict fp node from being created by falling into non-strict code path. 2019-12-19 11:39:50 -08:00
Jay Foad c5c935ab66 Make more use of MachineInstr::mayLoadOrStore. 2019-12-19 11:51:52 +00:00
Liu, Chen3 2f932b5729 Enable STRICT_FP_TO_SINT/UINT on X86 backend
This patch is mainly for custom lowering the vector operation.

Differential Revision: https://reviews.llvm.org/D71592
2019-12-19 14:49:13 +08:00
David Blaikie aaa5a5e7ff DebugInfo: Include DW_AT_base_addr even in gmlt with no inline functions
Since the address pool doesn't get populated in this case (due to the
lack of inlining, no child DIEs are added to the CU - so no addresses
are needed for the DIEs themselves) until the range list is emitted - at
the time the attributes are added to the CU, the address pool is empty.
So check whether the address pool will be used for the range lists & add
an addr_base if that's the case.
2019-12-18 17:14:28 -08:00
David Blaikie 64fa76ef55 Reapply "NFC: DebugInfo: Refactor RangeSpanList to be a struct, like DebugLocStream::List"
Move these data structures closer together so their emission code can
eventually share more of its implementation.

Was an egregious bug (completely untested, evidently) where I hadn't
inverted a DWARFv5 test as needed, so it was doing the exact opposite of
what was required & thus tried to emit a DWARFv5 range list header in
DWARFv4.

Reapply 8e04896288 which was
reverted in a8154e5e0c.
2019-12-18 16:28:19 -08:00
Ulrich Weigand 1946461344 [FPEnv] Strict versions of llvm.minimum/llvm.maximum
Add new intrinsics
   llvm.experimental.constrained.minimum
   llvm.experimental.constrained.maximum
as strict versions of llvm.minimum and llvm.maximum.

Includes SystemZ back-end support.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D71624
2019-12-18 21:35:28 +01:00
Craig Topper cfe316007f [SelectionDAGBuilder] Use getConstant instead of getTargetConstant to build the offset for struct types in getUniformBase.
getTargetConstant prevents any optimizations from operating on the
value and basically says its already been iseled. But since we
want the index to be in a register, this isn't true.

Prior to this we were generating a vbroadcast with an immediate
argument which is illegal and was flagged by the expensive checks
bot.
2019-12-18 10:44:28 -08:00
stozer 89d19d60ad Reapply: [DebugInfo] Correctly handle salvaged casts and split fragments at ISel
This reverts commit 1f3dd83cc1, reapplying
commit bb1b0bc4e5.

The original commit failed on some builds seemingly due to the use of a
bracketed constructor with an std::array, i.e. `std::array<> arr({...})`.
2019-12-18 16:26:42 +00:00
Daniel Sanders c3cb089a87 [gicombiner] Import tryCombineIndexedLoadStore()
Summary:
Now that arbitrary data is supported, import tryCombineIndexedLoadStore()

Depends on D69147

Reviewers: bogner, volkan

Reviewed By: volkan

Subscribers: hiraditya, arphaman, Petar.Avramovic, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69151
2019-12-18 14:41:38 +00:00
stozer 1f3dd83cc1 Revert "[DebugInfo] Correctly handle salvaged casts and split fragments at ISel"
Reverted due to build failure on windows bots.

This reverts commit bb1b0bc4e5.
2019-12-18 11:46:10 +00:00
stozer bb1b0bc4e5 [DebugInfo] Correctly handle salvaged casts and split fragments at ISel
Previously, LLVM had no functional way of performing casts inside of a
DIExpression(), which made salvaging cast instructions other than Noop
casts impossible. This patch enables the salvaging of casts by using the
DW_OP_LLVM_convert operator for SExt and Trunc instructions.

There is another issue which is exposed by this fix, in which fragment
DIExpressions (which are preserved more readily by this patch) for
values that must be split across registers in ISel trigger an assertion,
as the 'split' fragments extend beyond the bounds of the fragment
DIExpression causing an error. This patch also fixes this issue by
checking the fragment status of DIExpressions which are to be split, and
dropping fragments that are invalid.
2019-12-18 11:09:18 +00:00
Jay Foad 97ca7c2cc9 [AArch64] Enable clustering memory accesses to fixed stack objects
Summary:
r347747 added support for clustering mem ops with FI base operands
including support for fixed stack objects in shouldClusterFI, but
apparently this was never tested.

This patch fixes shouldClusterFI to work with scaled as well as
unscaled load/store instructions, and fixes the ordering of memory ops
in MemOpInfo::operator< to ensure that memory addresses always
increase, regardless of which direction the stack grows.

Subscribers: MatzeB, kristof.beyls, hiraditya, javed.absar, arphaman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71334
2019-12-18 09:46:11 +00:00
Anna Welker 7cd1cfdd6b [NFC][TTI] Add Alignment for isLegalMasked[Gather/Scatter]
Add an extra parameter so alignment can be taken under
consideration in gather/scatter legalization.

Differential Revision: https://reviews.llvm.org/D71610
2019-12-18 09:14:39 +00:00
Wang, Pengfei 8cc0b58673 [X86] Add calculation for elements in structures in getting uniform base for the Gather/Scatter intrinsic.
Summary: Add calculation for elements in structures in getting uniform
base for the Gather/Scatter intrinsic.

Reviewers: craig.topper, c-rhodes, RKSimon

Subscribers: hiraditya, llvm-commits, annita.zhang, LuoYuanke

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71442
2019-12-18 12:24:58 +08:00
Craig Topper c36773c78e [FPEnv][LegalizeTypes] Make ScalarizeVecOp_STRICT_FP_ROUND do its own replacements and return SDValue()
The caller will assert for nodes with more than 2 results unless
we return a null SDValue.

I tried to test this by copying an AArch64 test for ScalarizeVecOp_FP_ROUND.
While it did hit the assert and this commited fixed that. It also
hit a later problem that couldn't be fixed without adding strict
FP support to AArch64.
2019-12-17 15:17:43 -08:00
Craig Topper 84d8fa30f9 [FPEnv][LegalizeTypes][LegalizeDAG][AArch64] Few fixes/improvements for legalizing fp<->int conversion nodes.
This started with adding a test to support get code coverage on
ScalarizeVecOp_UnaryOp_StrictFP by copying an existing AArch64 test
and using constrained sitofp/uitofp intrinsics.

This found 3 separate issues:
-ScalarizeVecOp_UnaryOp_StrictFP needs to do its own replacement
 because the caller can't handle replacing multiple results.
-Missing integer promotion support for sitofp/uitofp
-Chain result not always assigned in ExpandLegalINT_TO_FP.

Committing them together so I can add the test case.
2019-12-17 14:37:00 -08:00
Sourabh Singh Tomar 399273e5eb Recommit "[DebugInfo] Refactored macro related generation,
added a test case for macinfo.dwo emission."

This was reverted in caa4120906,
since it was causing an assertion failure on Windows bots.
This revision is revised to fix that.

Original commit message -

[DebugInfo] Refactored macro related generation, added a test case for macinfo.dwo emission.

Reviewers: dblaikie, aprantl, jini.susan.george

Tags: #debug-info #llvm

Differential Revision: https://reviews.llvm.org/D71008
2019-12-18 02:12:59 +05:30
Sanjay Patel 6a77e36975 [SDAG] adjust isNegatibleForFree calculation to avoid crashing
This is an alternate fix for the bug discussed in D70595.
This also includes minimal tests for other in-tree targets to show the problem more
generally.

We check the number of uses as a predicate for whether some value is free to negate,
but that use count can change as we rewrite the expression in getNegatedExpression().
So something that was marked free to negate during the cost evaluation phase becomes
not free to negate during the rewrite phase (or the inverse - something that was not
free becomes free). This can lead to a crash/assert because we expect that everything
in an expression that is negatible to be handled in the corresponding code within
getNegatedExpression().

This patch adds a hack to work-around the case where we probably no longer detect
that either multiply operand of an FMA isNegatibleForFree which is assumed to be
true when we started rewriting the expression.

Differential Revision: https://reviews.llvm.org/D70975
2019-12-17 13:49:15 -05:00
Sanjay Patel 5b0251da1c Revert "[SDAG] remove use restriction in isNegatibleForFree() when called from getNegatedExpression()"
This reverts commit 36b1232ec5.
Need to adjust commit message - that was a leftover from the earlier version.
2019-12-17 13:47:59 -05:00
Sanjay Patel 36b1232ec5 [SDAG] remove use restriction in isNegatibleForFree() when called from getNegatedExpression()
This is an alternate fix for the bug discussed in D70595.
This also includes minimal tests for other in-tree targets to show the problem more
generally.

We check the number of uses as a predicate for whether some value is free to negate,
but that use count can change as we rewrite the expression in getNegatedExpression().
So something that was marked free to negate during the cost evaluation phase becomes
not free to negate during the rewrite phase (or the inverse - something that was not
free becomes free). This can lead to a crash/assert because we expect that everything
in an expression that is negatible to be handled in the corresponding code within
getNegatedExpression().

This patch adds a hack to work-around the case where we probably no longer detect
that either multiply operand of an FMA isNegatibleForFree which is assumed to be
true when we started rewriting the expression.

Differential Revision: https://reviews.llvm.org/D70975
2019-12-17 13:46:06 -05:00
Amaury Séchet ff6567cc77 [DAGCombiner] Add node back in the worklist in topological order in CommitTargetLoweringOpt
Summary:
Right now, DAGCombiner process the nodes in an iplementation defined order. This tends to be fragile as optimisation may or may not kick in depending on the traversal order.

This is part of a larger effort to get the DAGCombiner to process its node in topological order.

Reviewers: craig.topper, efriedma, RKSimon, lebedev.ri

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70921
2019-12-17 18:26:16 +01:00
Mitch Phillips 2423774cc2 Revert "Honor -fuse-init-array when os is not specified on x86"
This reverts commit aa5ee8f244.

This change broke the sanitizer buildbots. See comments at the patchset
(https://reviews.llvm.org/D71360) for more information.
2019-12-17 07:36:59 -08:00
Kevin P. Neal b1d8576b0a This adds constrained intrinsics for the signed and unsigned conversions
of integers to floating point.

This includes some of Craig Topper's changes for promotion support from
D71130.

Differential Revision: https://reviews.llvm.org/D69275
2019-12-17 10:06:51 -05:00
alex-t e7f585ed61 PostRA Machine Sink should take care of COPY defining register that is a sub-register by another COPY source operand
Differential Revision: https://reviews.llvm.org/D71132
2019-12-17 15:20:43 +03:00
Guillaume Chatelet 531c1161b9 Resubmit "[Alignment][NFC] Deprecate CreateMemCpy/CreateMemMove"
Summary:
This is a resubmit of D71473.

This patch introduces a set of functions to enable deprecation of IRBuilder functions without breaking out of tree clients.
Functions will be deprecated one by one and as in tree code is cleaned up.

This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: aaron.ballman, courbet

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71547
2019-12-17 10:07:46 +01:00
Raphael Isemann ccfab8e459 [ObjC][DWARF] Emit DW_AT_APPLE_objc_direct for methods marked as __attribute__((objc_direct))
Summary:
With DWARF5 it is no longer possible to distinguish normal methods and methods with `__attribute__((objc_direct))` by just looking at the debug information
as they are both now children of the of the DW_TAG_structure_type that defines them (before only the `__attribute__((objc_direct))` methods were children).

This means that in LLDB we are no longer able to create a correct Clang AST of a module by just looking at the debug information. Instead we would
need to call the Objective-C runtime to see which of the methods have a `__attribute__((objc_direct))` and then add the attribute to our own Clang AST
depending on what the runtime returns. This would mean that we either let the module AST be dependent on the Objective-C runtime (which doesn't
seem right) or we retroactively add the missing attribute to the imported AST in our expressions.

A third option is to annotate methods with `__attribute__((objc_direct))` as `DW_AT_APPLE_objc_direct` which is what this patch implements. This way
LLDB doesn't have to call the runtime for any `__attribute__((objc_direct))` method and the AST in our module will already be correct when we create it.

Reviewers: aprantl, SouraVX

Reviewed By: aprantl

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D71201
2019-12-17 09:40:36 +01:00
Craig Topper 13ce7c1291 [LegalizeTypes] Pre-size the SmallVectors in ScalarizeVecRes_StrictFPOp and SplitVecRes_StrictFPOp so we don't have to call push_back. NFCI
This avoids grow checking/handling in each iteration of the loop.
2019-12-16 23:42:13 -08:00
Craig Topper c738ebc1f5 [LegalizeTypes] Remove ScalarizeVecRes_STRICT_FP_ROUND in favor of just using ScalarizeVecRes_StrictFPOp. NFCI
It looks like ScalarizeVecRes_StrictFPOp can handle a variable
number of arguments with scalar and vector types so it should
be sufficient.
2019-12-16 23:42:13 -08:00
Craig Topper c4d2bb1ede [LegalizeTypes] Remove the call to SplitVecRes_UnaryOp from SplitVecRes_StrictFPOp. NFCI
It doesn't seem to do anything that SplitVecRes_StrictFPOp can't
do. SplitVecRes_StrictFPOp already handles nodes with a variable
number of arguments and a mix of scalar and vector arguments.
2019-12-16 23:42:13 -08:00
Craig Topper 4e48513b47 [SelectionDAG] Add the fpexcept flag to the SelectionDAG dumping output so we can better see when its not propagating.
We're currently losing this flag in type legalization and probably
other places when we expand strict fp nodes. This will make
reading logs easier.
2019-12-16 18:05:11 -08:00
Puyan Lotfi 204dfabfe6 [NFC][llvm][MIRVRegNamerUtils] Moving some switch cases and altering comments. 2019-12-16 18:50:26 -05:00
Puyan Lotfi f63b64c0c3 [llvm][MIRVRegNamerUtils] Adding hashing on CImm / FPImm MachineOperands.
This patch makes it so that cases where multiple instructions that
differ only in their ConstantInt or ConstantFP MachineOperand values no
longer collide. For instance:

%0:_(s1) = G_CONSTANT i1 true
%1:_(s1) = G_CONSTANT i1 false
%2:_(s32) = G_FCONSTANT float 1.0
%3:_(s32) = G_FCONSTANT float 0.0

Prior to this patch the first two instructions would collide together.
Also, the last two G_FCONSTANT instructions would also collide. Now they
will no longer collide.

Differential Revision: https://reviews.llvm.org/D71558
2019-12-16 18:25:04 -05:00
Kamlesh Kumar aa5ee8f244 Honor -fuse-init-array when os is not specified on x86
Currently -fuse-init-array option is not effective when target triple
does not specify os, on x86,x86_64.
i.e.

// -fuse-init-array is not honored.
$ clang -target i386 -fuse-init-array test.c -S

// -fuse-init-array is honored.
$ clang -target i386-linux -fuse-init-array test.c -S

This patch fixes first case.
And does cleanup.

Reviewers: rnk, craig.topper, fhahn, echristo

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D71360
2019-12-16 15:21:23 -08:00
Guillaume Chatelet 4658da10e4 Revert "[Alignment][NFC] Deprecate CreateMemCpy/CreateMemMove"
This reverts commit 181ab91efc.
2019-12-16 15:19:49 +01:00
Guillaume Chatelet 181ab91efc [Alignment][NFC] Deprecate CreateMemCpy/CreateMemMove
Summary:
This patch introduces a set of functions to enable deprecation of IRBuilder functions without breaking out of tree clients.
Functions will be deprecated one by one and as in tree code is cleaned up.

This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: arsenm, jvesely, nhaehnle, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71473
2019-12-16 13:35:55 +01:00
Valentin Churavy 5c29e8c65f [CodegenPrepare] Guard against degenerate branches
Summary:
Guard against a potential crash observed in https://github.com/JuliaLang/julia/issues/32994#issuecomment-524249628
If two branches are collapsed we can encounter a degenerate conditional branch `TBB==FBB`.
The subsequent code assumes that they differ, so we exit out early.

Reviewers: ributzka, spatel

Subscribers: loladiro, dexonsmith, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66657
2019-12-16 04:23:32 -05:00
Sanjay Patel 2afe864118 [DAG] Add SimplifyDemandedBits support for BSWAP
This exposes a shortcoming for AArch64, and that is tracked by PR40881:
https://bugs.llvm.org/show_bug.cgi?id=40881

Patch by: @RKSimon (Simon Pilgrim)

Differential Revision: https://reviews.llvm.org/D58017
2019-12-15 08:52:34 -05:00
Craig Topper 1dc0c8af5e [LegalizeTypes] Teach BitcastToInt_ATOMIC_SWAP to only create FP16_TO_FP when called from PromoteFloatResult.
There's also a call from SoftenFloatResult that should not be promoted.

The change test case would fail with the new RUN line prior to
this change.
2019-12-14 15:05:32 -08:00
Craig Topper 95ce8f9498 [LegalizeTypes] In PromoteFloatOp_SETCC, don't both querying for transforming the result type.
The result type is already legal, is doesnt' need to be
transformed.
2019-12-14 15:05:32 -08:00
Puyan Lotfi 816985c120 [NFC][llvm][MIRVRegNamerUtils] Refactoring GetHashableMO into switch-statement.
This refactors the if-statements handling the hashing of various
MachineOperand types into a switch-statement. The purpose is to cover
all the basis for all MachineOperand types while being very deliberate
about which MachineOperand types we are not handling and why (better
added comments). This patch is a NFC redo of https://reviews.llvm.org/D71396.
Much of the changes present in D71396 will come in smaller follow-up patches
that will add support for hashing the MachineOperand types that aren't
covered piece-meal with tests for each new case.
2019-12-14 02:31:07 -05:00
Roman Tereshin 8731799fc6 [Legalizer] Making artifact combining order-independent
Legalization algorithm is complicated by two facts:
1) While regular instructions should be possible to legalize in
   an isolated, per-instruction, context-free manner, legalization
   artifacts can only be eliminated in pairs, which could be deeply, and
   ultimately arbitrary nested: { [ () ] }, where which paranthesis kind
   depicts an artifact kind, like extend, unmerge, etc. Such structure
   can only be fully eliminated by simple local combines if they are
   attempted in a particular order (inside out), or alternatively by
   repeated scans each eliminating only one innermost pair, resulting in
   O(n^2) complexity.
2) Some artifacts might in fact be regular instructions that could (and
   sometimes should) be legalized by the target-specific rules. Which
   means failure to eliminate all artifacts on the first iteration is
   not a failure, they need to be tried as instructions, which may
   produce more artifacts, including the ones that are in fact regular
   instructions, resulting in a non-constant number of iterations
   required to finish the process.

I trust the recently introduced termination condition (no new artifacts
were created during as-a-regular-instruction-retrial of artifacts not
eliminated on the previous iteration) to be efficient in providing
termination, but only performing the legalization in full if and only if
at each step such chains of artifacts are successfully eliminated in
full as well.

Which is currently not guaranteed, as the artifact combines are applied
only once and in an arbitrary order that has to do with the order of
creation or insertion of artifacts into their worklist, which is a no
particular order.

In this patch I make a small change to the artifact combiner, making it
to re-insert into the worklist immediate (modulo a look-through copies)
artifact users of each vreg that changes its definition due to an
artifact combine.

Here the first scan through the artifacts worklist, while not
being done in any guaranteed order, only needs to find the innermost
pair(s) of artifacts that could be immediately combined out. After that
the process follows def-use chains, making them shorter at each step, thus
combining everything that can be combined in O(n) time.

Reviewers: volkan, aditya_nandakumar, qcolombet, paquette, aemerson, dsanders

Reviewed By: aditya_nandakumar, paquette

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71448
2019-12-13 15:45:18 -08:00
Roman Tereshin 18bf9670aa [Legalizer] Refactoring out legalizeMachineFunction
and introducing new unittests/CodeGen/GlobalISel/LegalizerTest.cpp
relying on it to unit test the entire legalizer algorithm (including the
top-level main loop).

See also https://reviews.llvm.org/D71448
2019-12-13 15:45:18 -08:00
Roman Tereshin 8207c81597 [Legalizer] More detailed debugging printing in main loop 2019-12-13 15:45:18 -08:00
Alex Richardson 11448eeb72 [NFC] Use SelectionDAG::getMemBasePlusOffset() instead of getNode(ISD::ADD)
Summary:
To find potential opportunities to use getMemBasePlusOffset() I looked at
all ISD::ADD uses found with the regex getNode\(ISD::ADD,.+,.+Ptr
in lib/CodeGen/SelectionDAG. If this patch is accepted I will convert
the files in the individual backends too.

The motivation for this change is our out-of-tree CHERI backend
(https://github.com/CTSRD-CHERI/llvm-project). We use a separate register
type to store pointers (128-bit capabilities, which are effectively
unforgeable and monotonic fat pointers). These capabilities permit a
reduced set of operations and therefore use a separate ValueType (iFATPTR).
to represent pointers implemented as capabilities.
Therefore, we need to avoid using ISD::ADD for our patterns that operate
on pointers and need to use a function that chooses ISD::ADD or a new
ISD::PTRADD opcode depending on the value type.

We originally added a new DAG.getPointerAdd() function, but after this
patch series we can modify the implementation of getMemBasePlusOffset()
instead. Avoiding direct uses of ISD::ADD for pointer types will
significantly reduce the amount of assertion/instruction selection
failures for us in future upstream merges.

Reviewers: spatel

Reviewed By: spatel

Subscribers: merge_guards_bot, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71207
2019-12-13 21:40:03 +00:00
Alex Richardson fc83f53a86 [NFC] Implement SelectionDAG::getObjectPtrOffset() using getMemBasePlusOffset()
Summary:
This change is preparatory work to use this helper functions in more places.
In order to make this change, getMemBasePlusOffset() has been extended to
also take a SDNodeFlags parameter.

The motivation for this change is our out-of-tree CHERI backend
(https://github.com/CTSRD-CHERI/llvm-project). We use a separate register
type to store pointers (128-bit capabilities, which are effectively
unforgeable and monotonic fat pointers). These capabilities permit a
reduced set of operations and therefore use a separate ValueType (iFATPTR).
to represent pointers implemented as capabilities.
Therefore, we need to avoid using ISD::ADD for our patterns that operate
on pointers and need to use a function that chooses ISD::ADD or a new
ISD::PTRADD opcode depending on the value type.

We originally added a new DAG.getPointerAdd() function, but after this
patch series we can modify the implementation of getMemBasePlusOffset()
instead. Avoiding direct uses of ISD::ADD for pointer types will
significantly reduce the amount of assertion/instruction selection
failures for us in future upstream merges.

Reviewers: spatel

Reviewed By: spatel

Subscribers: merge_guards_bot, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71206
2019-12-13 21:40:03 +00:00
Alex Richardson ea8888d1af [NFC] Add a SDValue overload for SelectionDAG::getMemBasePlusOffset()
Summary:
This change is preparatory work to use this helper functions in more places.
Currently the function only allows integer constants offsets, but there
are cases where we can use an existing SDValue parameter.

The motivation for this change is our out-of-tree CHERI backend
(https://github.com/CTSRD-CHERI/llvm-project). We use a separate register
type to store pointers (128-bit capabilities, which are effectively
unforgeable and monotonic fat pointers). These capabilities permit a
reduced set of operations and therefore use a separate ValueType (iFATPTR).
to represent pointers implemented as capabilities.
Therefore, we need to avoid using ISD::ADD for our patterns that operate
on pointers and need to use a function that chooses ISD::ADD or a new
ISD::PTRADD opcode depending on the value type.

We originally added a new DAG.getPointerAdd() function, but after this
patch series we can modify the implementation of getMemBasePlusOffset()
instead. Avoiding direct uses of ISD::ADD for pointer types will
significantly reduce the amount of assertion/instruction selection
failures for us in future upstream merges.

Reviewers: spatel, craig.topper

Reviewed By: spatel, craig.topper

Subscribers: craig.topper, merge_guards_bot, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71205
2019-12-13 21:40:03 +00:00
Alex Richardson d9bb70acd7 [NFC] Change SelectionDAG::getMemBasePlusOffset() to use int64_t
Summary:
This change is preparatory work to use this helper functions in more places.
Currently the function only allows positive offsets, but there are cases
where we want to subtract an offset from an existing pointer.

The motivation for this change is our out-of-tree CHERI backend
(https://github.com/CTSRD-CHERI/llvm-project). We use a separate register
type to store pointers (128-bit capabilities, which are effectively
unforgeable and monotonic fat pointers). These capabilities permit a
reduced set of operations and therefore use a separate ValueType (iFATPTR).
to represent pointers implemented as capabilities.
Therefore, we need to avoid using ISD::ADD for our patterns that operate
on pointers and need to use a function that chooses ISD::ADD or a new
ISD::PTRADD opcode depending on the value type.

We originally added a new DAG.getPointerAdd() function, but after this
patch series we can modify the implementation of getMemBasePlusOffset()
instead. Avoiding direct uses of ISD::ADD for pointer types will
significantly reduce the amount of assertion/instruction selection
failures for us in future upstream merges.

Reviewers: spatel

Reviewed By: spatel

Subscribers: merge_guards_bot, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71204
2019-12-13 21:40:03 +00:00