Commit Graph

296 Commits

Author SHA1 Message Date
Kazu Hirata 3f3930a451 Remove redundaunt virtual specifiers (NFC)
Identified with tidy-modernize-use-override.
2022-07-25 23:00:59 -07:00
Nikita Popov 7283f48a05 [IR] Remove support for insertvalue constant expression
This removes the insertvalue constant expression, as part of
https://discourse.llvm.org/t/rfc-remove-most-constant-expressions/63179.
This is very similar to the extractvalue removal from D125795.
insertvalue is also not supported in bitcode, so no auto-ugprade
is necessary.

ConstantExpr::getInsertValue() can be replaced with
IRBuilder::CreateInsertValue() or ConstantFoldInsertValueInstruction(),
depending on whether a constant result is required (with the latter
being fallible).

The ConstantExpr::hasIndices() and ConstantExpr::getIndices()
methods also go away here, because there are no longer any constant
expressions with indices.

Differential Revision: https://reviews.llvm.org/D128719
2022-07-04 09:27:22 +02:00
Nikita Popov 16033ffdd9 [ConstExpr] Remove more leftovers of extractvalue expression (NFC)
Remove some leftover bits of extractvalue handling after the
removal in D125795.
2022-06-29 10:45:19 +02:00
Kazu Hirata d66cbc565a Don't use Optional::hasValue (NFC) 2022-06-20 20:26:05 -07:00
Fraser Cormack 6be5e875be [RISCV][VP] Add basic RVV codegen for vp.icmp
This patch adds the minimum required to successfully lower vp.icmp via
the new ISD::VP_SETCC node to RVV instructions.

Regular ISD::SETCC goes through a lot of canonicalization which targets
may rely on which has not hereto been ported to VP_SETCC. It also
supports expansion of individual condition codes and a non-boolean
return type. Support for all of that will follow in later patches.

In the case of RVV this largely isn't a problem as the vector integer
comparison instructions are plentiful enough that it can lower all
VP_SETCC nodes on legal integer vectors except for boolean vectors,
which regular SETCC folds away immediately into logical operations.

Floating-point VP_SETCC operations aren't as well supported in RVV and
the backend relies on condition code expansion, so support for those
operations will come in later patches.

Portions of this code were taken from the VP reference patches.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D122743
2022-04-06 16:51:22 +01:00
Michael Gottesman e24f534879 [debug-info] As an NFC commit, refactor EmitFuncArgumentDbgValue so that it can be extended to support llvm.dbg.addr.
The reason why I am making this change is that before this commit,
EmitFuncArgumentDbgValue relied on a boolean flag IsDbgDeclare both to signal
that a DBG_VALUE should be made to be indirect /and/ that the original intrinsic
was a dbg.declare. This is no longer always true if we add support for handling
dbg.addr since we will have an indirect DBG_VALUE that is a different intrinsic
from dbg.declare.

With that in mind, in this NFC patch, we prepare for future fixes by introducing
a 3 case-enum argument to EmitFuncArgumentDbgValue that allows the caller to
explicitly specify how the argument's DBG_VALUE should be emitted. This then
allows us to turn the indirect checks into a != FuncArgumentDbgValueKind::Value
and prepare us for a future where we add support here for llvm.dbg.addr
directly.

rdar://83957028

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D122945
2022-04-01 17:07:28 -07:00
Craig Topper 85eae45520 [SelectionDAG] Move extension type for ConstantSDNode from getCopyToRegs to HandlePHINodesInSuccessorBlocks.
D122053 set the ExtendType for ConstantSDNodes in getCopyToRegs to
ZERO_EXTEND to match assumptions in ComputePHILiveOutRegInfo. PHIs
are probably not the only way ConstantSDNodeNodes can get to
getCopyToRegs.

This patch adds an ExtendType parameter to CopyValueToVirtualRegister and
has HandlePHINodesInSuccessorBlocks pass ISD::ZERO_EXTEND for ConstantInts.
This way we only affect ConstantSDNodes for PHIs.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D122171
2022-03-30 11:32:43 -07:00
Lorenzo Albano 28cfa764c2 [VP] Strided loads/stores
This patch introduces two new experimental IR intrinsics and SDAG nodes
to represent vector strided loads and stores.

Reviewed By: simoll

Differential Revision: https://reviews.llvm.org/D114884
2022-03-10 18:46:54 +01:00
David Sherwood 3257f63bbd [NFC][CodeGen] Remove rarely used DL variable from SelectionDAGBuilder
There is a pointer to the DataLayout in SelectionDAGBuilder called
'DL' that is hardly ever used. In most cases the code seems to just
use `DAG.getDataLayout()` instead. Given that DL is also often used
as a shadowed variable for the debug location it seems sensible to
just kill off the few remaining uses and be consistent with the rest
of the code.

Differential Revision: https://reviews.llvm.org/D114451
2021-12-08 17:05:46 +00:00
Fraser Cormack 3460cc2585 [VP] Propagate align parameter attr on VP load/store to ISel
This patch fixes a case where the 'align' parameter attribute on the
pointer operands to llvm.vp.load and llvm.vp.store was being dropped
during the conversion to the SelectionDAG. The default alignment
equal to the ABI type alignment of the vector type was kept. It also
updates the documentation to reflect the fact that the parameter
attribute is now properly supported.

Reviewed By: simoll

Differential Revision: https://reviews.llvm.org/D114422
2021-12-07 10:16:16 +00:00
Amara Emerson cfef1803dd [GlobalISel] Port over the SelectionDAG stack protector codegen feature.
This is a port of the feature that allows the StackProtector pass to omit
checking code for stack canary checks, and rely on SelectionDAG to do it at a
later stage. The reasoning behind this seems to be to prevent the IR checking
instructions from hindering tail-call optimizations during codegen.

Here we allow GlobalISel to also use that scheme. Doing so requires that we
do some analysis using some factored-out code to determine where to generate
code for the epilogs.

Not every case is handled in this patch since we don't have support for all
targets that exercise different stack protector schemes.

Differential Revision: https://reviews.llvm.org/D98200
2021-10-04 21:33:44 -07:00
Hussain Kadhem 524ded7d01 [VP] implementation of sdag support for VP memory intrinsics
Followup to D99355: SDAG support for vector-predicated load/store/gather/scatter.

Reviewed By: frasercrmck

Differential Revision: https://reviews.llvm.org/D105871
2021-08-31 17:01:50 +02:00
Tim Northover 9ff2eb1ea5 SwiftTailCC: teach verifier musttail rules applicable to this CC.
SwiftTailCC has a different set of requirements than the C calling convention
for a tail call. The exact argument sequence doesn't have to match, but fewer
ABI-affecting attributes are allowed.

Also make sure the musttail diagnostic triggers if a musttail call isn't
actually a tail call.
2021-05-28 11:12:00 +01:00
cynecx 8ec9fd4839 Support unwinding from inline assembly
I've taken the following steps to add unwinding support from inline assembly:

1) Add a new `unwind` "attribute" (like `sideeffect`) to the asm syntax:

```
invoke void asm sideeffect unwind "call thrower", "~{dirflag},~{fpsr},~{flags}"()
    to label %exit unwind label %uexit
```

2.) Add Bitcode writing/reading support + LLVM-IR parsing.

3.) Emit EHLabels around inline assembly lowering (SelectionDAGBuilder + GlobalISel) when `InlineAsm::canThrow` is enabled.

4.) Tweak InstCombineCalls/InlineFunction pass to not mark inline assembly "calls" as nounwind.

5.) Add clang support by introducing a new clobber: "unwind", which lower to the `canThrow` being enabled.

6.) Don't allow unwinding callbr.

Reviewed By: Amanieu

Differential Revision: https://reviews.llvm.org/D95745
2021-05-13 19:13:03 +01:00
David Sherwood 748ae5281d [IR][SVE] Add new llvm.experimental.stepvector intrinsic
This patch adds a new llvm.experimental.stepvector intrinsic,
which takes no arguments and returns a linear integer sequence of
values of the form <0, 1, ...>. It is primarily intended for
scalable vectors, although it will work for fixed width vectors
too. It is intended that later patches will make use of this
new intrinsic when vectorising induction variables, currently only
supported for fixed width. I've added a new CreateStepVector
method to the IRBuilder, which will generate a call to this
intrinsic for scalable vectors and fall back on creating a
ConstantVector for fixed width.

For scalable vectors this intrinsic is lowered to a new ISD node
called STEP_VECTOR, which takes a single constant integer argument
as the step. During lowering this argument is set to a value of 1.
The reason for this additional argument at the codegen level is
because in future patches we will introduce various generic DAG
combines such as

  mul step_vector(1), 2 -> step_vector(2)
  add step_vector(1), step_vector(1) -> step_vector(2)
  shl step_vector(1), 1 -> step_vector(2)
  etc.

that encourage a canonical format for all targets. This hopefully
means all other targets supporting scalable vectors can benefit
from this too.

I've added cost model tests for both fixed width and scalable
vectors:

  llvm/test/Analysis/CostModel/AArch64/neon-stepvector.ll
  llvm/test/Analysis/CostModel/AArch64/sve-stepvector.ll

as well as codegen lowering tests for fixed width and scalable
vectors:

  llvm/test/CodeGen/AArch64/neon-stepvector.ll
  llvm/test/CodeGen/AArch64/sve-stepvector.ll

See this thread for discussion of the intrinsic:
https://lists.llvm.org/pipermail/llvm-dev/2021-January/147943.html
2021-03-23 10:43:35 +00:00
Cullen Rhodes 2750f3ed31 [IR] Introduce llvm.experimental.vector.splice intrinsic
This patch introduces a new intrinsic @llvm.experimental.vector.splice
that constructs a vector of the same type as the two input vectors,
based on a immediate where the sign of the immediate distinguishes two
variants. A positive immediate specifies an index into the first vector
and a negative immediate specifies the number of trailing elements to
extract from the first vector.

For example:

  @llvm.experimental.vector.splice(<A,B,C,D>, <E,F,G,H>, 1) ==> <B, C, D, E>  ; index
  @llvm.experimental.vector.splice(<A,B,C,D>, <E,F,G,H>, -3) ==> <B, C, D, E> ; trailing element count

These intrinsics support both fixed and scalable vectors, where the
former is lowered to a shufflevector to maintain existing behaviour,
although while marked as experimental the recommended way to express
this operation for fixed-width vectors is to use shufflevector. For
scalable vectors where it is not possible to express a shufflevector
mask for this operation, a new ISD node has been implemented.

This is one of the named shufflevector intrinsics proposed on the
mailing-list in the RFC at [1].

Patch by Paul Walker and Cullen Rhodes.

[1] https://lists.llvm.org/pipermail/llvm-dev/2020-November/146864.html

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D94708
2021-03-09 10:44:22 +00:00
gbtozers 93b170ea24 [DebugInfo] Handle dbg.values with multiple variable location operands in ISel
This patch adds partial support in Instruction Selection for dbg.values that use
a DIArgList. This patch does not add support for producing DBG_VALUE_LIST, but
adds the logic for processing DIArgLists within the ISel pass. This change is
largely focused on handleDebugValue and some of the functions that it calls.
Outside of this, salvageDebugInfo and transferDbgValues have been modified to
replace individual operands instead of the entire value; dangling debug info for
variadic debug values is not currently supported (but may be added later).

Differential Revision: https://reviews.llvm.org/D88589
2021-03-09 09:48:03 +00:00
Caroline Concatto 2d728bbff5 [CodeGen][SelectionDAG]Add new intrinsic experimental.vector.reverse
This patch adds  a new intrinsic experimental.vector.reduce that takes a single
vector and returns a vector of matching type but with the original lane order
 reversed. For example:

```
vector.reverse(<A,B,C,D>) ==> <D,C,B,A>
```

The new intrinsic supports fixed and scalable vectors types.
The fixed-width vector relies on shufflevector to maintain existing behaviour.
Scalable vector uses the new ISD node - VECTOR_REVERSE.

This new intrinsic is one of the named shufflevector intrinsics proposed on the
mailing-list in the RFC at [1].

Patch by Paul Walker (@paulwalker-arm).

[1] https://lists.llvm.org/pipermail/llvm-dev/2020-November/146864.html

Differential Revision: https://reviews.llvm.org/D94883
2021-02-15 13:39:43 +00:00
Simon Moll 3ffbc79357 [VP] Build VP SDNodes
Translate VP intrinsics to VP_* SDNodes.  The tests check whether a
matching vp_* SDNode is emitted.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D91441
2020-12-09 11:36:51 +01:00
Francesco Petrogalli f6150aa41a [SelectionDAGBuilder] Update signature of `getRegsAndSizes()`.
The mapping between registers and relative size has been updated to
use TypeSize to account for the size of scalable EVTs.

The patch is a NFCI, if not for the fact that with this change the
function `getUnderlyingArgRegs` does not raise a warning for implicit
conversion of `TypeSize` to `unsigned` when generating machine code
from the test added to the patch.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D92096
2020-11-30 17:38:51 +00:00
Dávid Bolvanský 179e15d53a [SystemZ] Optimize bcmp calls (PR47420)
Solves https://bugs.llvm.org/show_bug.cgi?id=47420

Reviewed By: uweigand

Differential Revision: https://reviews.llvm.org/D87988
2020-09-25 17:55:39 +02:00
Bill Wendling 0c0c57f7b2 Revert "[CodeGen] Postprocess PHI nodes for callbr"
Accidental commit.

This reverts commit 7f4c940bd0.
2020-09-24 14:35:23 -07:00
Bill Wendling 7f4c940bd0 [CodeGen] Postprocess PHI nodes for callbr
When processing PHI nodes after a callbr, we need to make sure that the
PHI nodes on the default branch are resolved after the callbr
(inserted after INLINEASM_BR). The PHI node values on the indirect
branches are processed before the INLINEASM_BR.

Differential Revision: https://reviews.llvm.org/D86260
2020-09-24 14:34:28 -07:00
Simon Pilgrim bee79cdcc6 SelectionDAGBuilder.h - remove unnecessary includes. NFCI.
Reduce to forward declarations and move implicit dependencies down to the cpp files.
2020-09-15 12:18:22 +01:00
Craig Topper b1e68f885b [SelectionDAGBuilder] Pass fast math flags to getNode calls rather than trying to set them after the fact.:
This removes the after the fact FMF handling from D46854 in favor of passing fast math flags to getNode. This should be a superset of D87130.

This required adding a SDNodeFlags to SelectionDAG::getSetCC.

Now we manage to contant fold some stuff undefs during the
initial getNode that we don't do in later DAG combines.

Differential Revision: https://reviews.llvm.org/D87200
2020-09-08 15:27:21 -07:00
Cameron McInally 31c7a2fd5c [FPEnv] Don't transform FSUB(-0,X)->FNEG(X) in SelectionDAGBuilder.
This patch stops unconditionally transforming FSUB(-0,X) into an FNEG(X) while building the DAG. There is also one small change to handle the new FSUB(-0,X) similarly to FNEG(X) in the AMDGPU backend.

Differential Revision: https://reviews.llvm.org/D84056
2020-08-03 10:22:25 -05:00
Philip Reames 98a87c65a3 [Statepoint] Reduce scope of usage of ImmutableStatepoint
Can't quite fully remove it yet as some more items need sunk the GCStatepointInst class from the wrapper, but we can at least reduce scope.
2020-05-27 18:57:42 -07:00
James Y Knight e9536795a3 Add comment for SelectionDAGBuilder::SL field. 2020-05-12 10:46:08 -04:00
Simon Pilgrim 46de0d5fe9 SelectionDAGBuilder.h - remove unused includes + forward declarations. NFC.
Replace SelectionDAG.h include with SelectionDAG forward declaration.
2020-04-19 12:38:41 +01:00
Craig Topper 944cc5e0ab [SelectionDAGBuilder][CGP][X86] Move some of SDB's gather/scatter uniform base handling to CGP.
I've always found the "findValue" a little odd and
inconsistent with other things in SDB.

This simplfifies the code in SDB to just handle a splat constant
address or a 2 operand GEP in the same BB. This removes the
need for "findValue" since the operands to the GEP are
guaranteed to be available. The splat constant handling is
new, but was needed to avoid regressions due to constant
folding combining GEPs created in CGP.

CGP is now responsible for canonicalizing gather/scatters into
this form. The pattern I'm using for scalarizing, a scalar GEP
followed by a GEP with an all zeroes index, seems to be subject
to constant folding that the insertelement+shufflevector was not.

Differential Revision: https://reviews.llvm.org/D76947
2020-04-16 17:49:22 -07:00
Craig Topper 113f37a1f9 [CallSite removal][TargetLowering] Replace ImmutableCallSite with CallBase
Differential Revision: https://reviews.llvm.org/D77995
2020-04-13 13:50:15 -07:00
Craig Topper 806763efcf [CallSite removal][SelectionDAGBuilder] Use CallBase instead of ImmutableCallSite in visitPatchpoint.
Differential Revision: https://reviews.llvm.org/D77932
2020-04-11 13:07:31 -07:00
Craig Topper f49f6cf91e [CallSite removal][SelectionDAGBuilder] Remove most CallSite usage from visitInlineAsm.
I only left it at the interface to ParseConstraints since that
needs updates to other callers in different files. I'll do that
as a follow up.

Differential Revision: https://reviews.llvm.org/D77892
2020-04-10 19:23:33 -07:00
Ulrich Weigand 81ee484484 [FPEnv] Fix chain handling regression after 04a8696
Code in getRoot made the assumption that every node in PendingLoads
must always itself have a dependency on the current DAG root node.

After the changes in 04a8696, it turns out that this assumption no
longer holds true, causing wrong codegen in some cases (e.g. stores
after constrained FP intrinsics might get deleted).

To fix this, we now need to make sure that the TokenFactor created
by getRoot always includes the previous root, if there is no implicit
dependency already present.

The original getControlRoot code already has exactly this check,
so this patch simply reuses that code now for getRoot as well.
This fixes the regression.

NFC if no constrained FP intrinsic is present.
2020-01-14 14:10:57 +01:00
Ulrich Weigand 04a86966fb [FPEnv] Fix chain handling for fpexcept.strict nodes
We need to ensure that fpexcept.strict nodes are not optimized away even if
the result is unused. To do that, we need to chain them into the block's
terminator nodes, like already done for PendingExcepts.

This patch adds two new lists of pending chains, PendingConstrainedFP and
PendingConstrainedFPStrict to hold constrained FP intrinsic nodes without
and with fpexcept.strict markers. This allows not only to solve the above
problem, but also to relax chains a bit further by no longer flushing all
FP nodes before a store or other memory access. (They are still flushed
before nodes with other side effects.)

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D72341
2020-01-13 14:38:49 +01:00
aqjune e87d71668e [IR] Redefine Freeze instruction
Summary:
This patch redefines freeze instruction from being UnaryOperator to a subclass of UnaryInstruction.

ConstantExpr freeze is removed, as discussed in the previous review.
FreezeOperator is not added because there's no ConstantExpr freeze.
`freeze i8* null` test is added to `test/Bindings/llvm-c/freeze.ll` as well, because the null pointer-related bug in `tools/llvm-c/echo.cpp` is now fixed.
InstVisitor has visitFreeze now because freeze is not unaryop anymore.

Reviewers: whitequark, deadalnix, craig.topper, jdoerfert, lebedev.ri

Reviewed By: craig.topper, lebedev.ri

Subscribers: regehr, nlopes, mehdi_amini, hiraditya, steven_wu, dexonsmith, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69932
2019-11-12 10:49:00 +09:00
aqjune 58acbce3de [IR] Add Freeze instruction
Summary:
- Define Instruction::Freeze, let it be UnaryOperator
- Add support for freeze to LLLexer/LLParser/BitcodeReader/BitcodeWriter
  The format is `%x = freeze <ty> %v`
- Add support for freeze instruction to llvm-c interface.
- Add m_Freeze in PatternMatch.
- Erase freeze when lowering IR to SelDag.

Reviewers: deadalnix, hfinkel, efriedma, lebedev.ri, nlopes, jdoerfert, regehr, filcab, delcypher, whitequark

Reviewed By: lebedev.ri, jdoerfert

Subscribers: jfb, kristof.beyls, hiraditya, lebedev.ri, steven_wu, dexonsmith, xbolva00, delcypher, spatel, regehr, trentxintong, vsk, filcab, nlopes, mehdi_amini, deadalnix, llvm-commits

Differential Revision: https://reviews.llvm.org/D29011
2019-11-05 15:54:56 +09:00
Jonas Devlieghere 0eaee545ee [llvm] Migrate llvm::make_unique to std::make_unique
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.

llvm-svn: 369013
2019-08-15 15:54:37 +00:00
Amara Emerson 829037a914 Factor out SelectionDAG's switch analysis and lowering into a separate component.
In order for GlobalISel to re-use the significant amount of analysis and
optimization code in SDAG's switch lowering, we first have to extract it and
create an interface to be used by both frameworks.

No test changes as it's NFC.

Differential Revision: https://reviews.llvm.org/D62745

llvm-svn: 362857
2019-06-08 00:05:17 +00:00
Tim Northover 3d7a057b0d CodeGen: factor out swifterror value tracking.
llvm-svn: 361607
2019-05-24 08:39:43 +00:00
Guillaume Chatelet e386a01e84 [NFC] Refactor visitIntrinsicCall so it doesn't return a const char*
Summary: API simplification

Reviewers: courbet

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61306

llvm-svn: 361140
2019-05-20 11:01:30 +00:00
Guillaume Chatelet a760e69840 Revert "[NFC] Refactor visitIntrinsicCall so it doesn't return a const char*"
This reverts commit 706d3cd6388cc3446aab282f3af879862b10cbed.

llvm-svn: 361130
2019-05-20 09:00:12 +00:00
Guillaume Chatelet fa8c152576 [NFC] Refactor visitIntrinsicCall so it doesn't return a const char*
Summary: API simplification

Reviewers: courbet

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61306

llvm-svn: 361129
2019-05-20 08:52:10 +00:00
Hans Wennborg 800b12f90a Switch lowering: exploit unreachable fall-through when lowering case range cluster
In the example below, we would previously emit two range checks, one for cases
1--3 and one for 4--6. This patch makes us exploit the fact that the
fall-through is unreachable and only one range check is necessary.

  switch i32 %i, label %default [
    i32 1,  label %bb1
    i32 2,  label %bb1
    i32 3,  label %bb1
    i32 4,  label %bb2
    i32 5,  label %bb2
    i32 6,  label %bb2
  ]
  default: unreachable

llvm-svn: 357252
2019-03-29 13:40:05 +00:00
Hans Wennborg 5c0d7a24e8 Re-commit r355490 "[CodeGen] Omit range checks from jump tables when lowering switches with unreachable default"
Original commit by Ayonam Ray.

This commit adds a regression test for the issue discovered in the
previous commit: that the range check for the jump table can only be
omitted if the fall-through destination of the jump table is
unreachable, which isn't necessarily true just because the default of
the switch is unreachable.

This addresses the missing optimization in PR41242.

> During the lowering of a switch that would result in the generation of a
> jump table, a range check is performed before indexing into the jump
> table, for the switch value being outside the jump table range and a
> conditional branch is inserted to jump to the default block. In case the
> default block is unreachable, this conditional jump can be omitted. This
> patch implements omitting this conditional branch for unreachable
> defaults.
>
> Differential Revision: https://reviews.llvm.org/D52002
> Reviewers: Hans Wennborg, Eli Freidman, Roman Lebedev

llvm-svn: 357067
2019-03-27 14:10:11 +00:00
Yi Kong 74b874ac4c Fix nondeterminism introduced in r353954
DenseMap iteration order is not guaranteed, use MapVector instead.

Fix provided by srhines.

Differential Revision: https://reviews.llvm.org/D59807

llvm-svn: 356988
2019-03-26 12:18:08 +00:00
Alexander Kornienko 3d467a890e Revert "[CodeGen] Omit range checks from jump tables when lowering switches with unreachable default"
This reverts commit 2a0f2c5ef3 (r355490).

The commit causes an assertion failure when compiling LLVM code:
$ cat repro.cpp
class QQQ {
public:
  bool x() const;
  bool y() const;
  unsigned getSizeInBits() const {
    if (y() || x())
      return getScalarSizeInBits();
    return getScalarSizeInBits() * 2;
  }
  unsigned getScalarSizeInBits() const;
};
int f(const QQQ &Ty) {
  switch (Ty.getSizeInBits()) {
    case 1:
    case 8:
      return 0;
    case 16:
      return 1;
    case 32:
      return 2;
    case 64:
      return 3;
    default:
      __builtin_unreachable();
  }
}
$ clang -O2 -o repro.o repro.cpp
assert.h assertion failed at llvm/include/llvm/ADT/ilist_iterator.h:139 in llvm::ilist_iterator::reference llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::MachineInstr, true, true, void>, true, false>::operator*() const [OptionsT = llvm::ilist_detail::node_options<llvm::MachineInstr, true, true, void>, IsReverse = true, IsConst = false]: !NodePtr->isKnownSentinel()
*** Check failure stack trace: ***
    @     0x558aab4afc10  __assert_fail
    @     0x558aa885479b  llvm::ilist_iterator<>::operator*()
    @     0x558aa8854715  llvm::MachineInstrBundleIterator<>::operator*()
    @     0x558aa92c33c3  llvm::X86InstrInfo::optimizeCompareInstr()
    @     0x558aa9a9c251  (anonymous namespace)::PeepholeOptimizer::optimizeCmpInstr()
    @     0x558aa9a9b371  (anonymous namespace)::PeepholeOptimizer::runOnMachineFunction()
    @     0x558aa99a4fc8  llvm::MachineFunctionPass::runOnFunction()
    @     0x558aab019fc4  llvm::FPPassManager::runOnFunction()
    @     0x558aab01a3a5  llvm::FPPassManager::runOnModule()
    @     0x558aab01aa9b  (anonymous namespace)::MPPassManager::runOnModule()
    @     0x558aab01a635  llvm::legacy::PassManagerImpl::run()
    @     0x558aab01afe1  llvm::legacy::PassManager::run()
    @     0x558aa5914769  (anonymous namespace)::EmitAssemblyHelper::EmitAssembly()
    @     0x558aa5910f44  clang::EmitBackendOutput()
    @     0x558aa5906135  clang::BackendConsumer::HandleTranslationUnit()
    @     0x558aa6d165ad  clang::ParseAST()
    @     0x558aa6a94e22  clang::ASTFrontendAction::ExecuteAction()
    @     0x558aa590255d  clang::CodeGenAction::ExecuteAction()
    @     0x558aa6a94840  clang::FrontendAction::Execute()
    @     0x558aa6a38cca  clang::CompilerInstance::ExecuteAction()
    @     0x558aa4e2294b  clang::ExecuteCompilerInvocation()
    @     0x558aa4df6200  cc1_main()
    @     0x558aa4e1b37f  ExecuteCC1Tool()
    @     0x558aa4e1a725  main
    @     0x7ff20d56abbd  __libc_start_main
    @     0x558aa4df51c9  _start

llvm-svn: 355515
2019-03-06 15:23:50 +00:00
Ayonam Ray 2a0f2c5ef3 [CodeGen] Omit range checks from jump tables when lowering switches with unreachable default
During the lowering of a switch that would result in the generation of a
jump table, a range check is performed before indexing into the jump
table, for the switch value being outside the jump table range and a
conditional branch is inserted to jump to the default block. In case the
default block is unreachable, this conditional jump can be omitted. This
patch implements omitting this conditional branch for unreachable
defaults.

Differential Revision: https://reviews.llvm.org/D52002
Reviewers: Hans Wennborg, Eli Freidman, Roman Lebedev

llvm-svn: 355490
2019-03-06 10:01:02 +00:00
Ayonam Ray af92b7a3b8 Reversing the commit of revision 355483 since it is giving a regression on a newly added test.
llvm-svn: 355487
2019-03-06 07:51:28 +00:00
Ayonam Ray 6025fa8e30 [CodeGen] Omit range checks from jump tables when lowering switches with unreachable default
During the lowering of a switch that would result in the generation of a
jump table, a range check is performed before indexing into the jump
table, for the switch value being outside the jump table range and a
conditional branch is inserted to jump to the default block. In case the
default block is unreachable, this conditional jump can be omitted. This
patch implements omitting this conditional branch for unreachable
defaults.

Differential Revision: https://reviews.llvm.org/D52002
Reviewers: Hans Wennborg, Eli Freidman, Roman Lebedev

llvm-svn: 355483
2019-03-06 07:27:45 +00:00