Commit Graph

2814 Commits

Author SHA1 Message Date
Matt Arsenault 0c687390fe DAG: Constant fold fp16_to_fp/fp16_to_fp
This fixes emitting conversions of constants on targets
without legal f16 that need to use these for legalization.

llvm-svn: 293499
2017-01-30 16:57:41 +00:00
Saleem Abdulrasool 5282eed06c ARM: support `-mlong-calls` with AEABI TLS on ELF
Support lowering AEABI TLS access (__aeabi_read_tp) with long calls.
This requires adjusting the call sequence to use an indirect call to get
full addressability.

Resolves PR31769!

llvm-svn: 293433
2017-01-29 16:46:22 +00:00
Matthew Simpson 3650df13be [ARM/AArch64] Relocate and update InterleavedAccessPass tests (NFC)
The interleaved access pass is an IR-to-IR transformation that runs before code
generation. It matches interleaved memory operations to target-specific
intrinsics (that are later lowered to load and store multiple instructions on
ARM/AArch64). We place tests for similar passes (e.g., GlobalMergePass) under
test/Transforms. This patch moves the InterleavedAccessPass tests out of
test/CodeGen and into target-specific directories under
test/Transforms/InterleavedAccess.

Although the pass is an IR pass, many of the existing tests were llc tests
rather opt tests. For example, the tests would check for ldN/stN instructions
generated by llc rather than the intrinsic calls the pass actually inserts.
Thus, this patch updates all tests to be opt tests that check for the inserted
intrinsics. We already have separate CodeGen tests that ensure we lower the
interleaved access intrinsics to their corresponding ldN/stN instructions. In
addition to migrating the tests to opt, this patch also performs some minor
clean-up (to ensure consistent naming, etc.).

Differential Revision: https://reviews.llvm.org/D29184

llvm-svn: 293309
2017-01-27 17:33:16 +00:00
Saleem Abdulrasool 26c00e3700 ARM: fix vectorized division on WoA
The Windows on ARM target uses custom division for normal division as
the backend needs to insert division-by-zero checks.  However, it is
designed to only handle non-vectorized division.  ARM has custom
lowering for vectorized division as that can avoid loading registers
with the values and invoke a division routine for each one, preferring
to lower using NEON instructions.  Fall back to the custom lowering for
the NEON instructions if we encounter a vectorized division.

Resolves PR31778!

llvm-svn: 293259
2017-01-27 03:41:53 +00:00
Nirav Dave d32a421f75 Revert "In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled."
This reverts commit r293184 which is failing in LTO builds

llvm-svn: 293188
2017-01-26 16:46:13 +00:00
Nirav Dave de6516c466 In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled.
* Simplify Consecutive Merge Store Candidate Search

    Now that address aliasing is much less conservative, push through
    simplified store merging search and chain alias analysis which only
    checks for parallel stores through the chain subgraph. This is cleaner
    as the separation of non-interfering loads/stores from the
    store-merging logic.

    When merging stores search up the chain through a single load, and
    finds all possible stores by looking down from through a load and a
    TokenFactor to all stores visited.

    This improves the quality of the output SelectionDAG and the output
    Codegen (save perhaps for some ARM cases where we correctly constructs
    wider loads, but then promotes them to float operations which appear
    but requires more expensive constant generation).

    Some minor peephole optimizations to deal with improved SubDAG shapes (listed below)

    Additional Minor Changes:

      1. Finishes removing unused AliasLoad code

      2. Unifies the chain aggregation in the merged stores across code
         paths

      3. Re-add the Store node to the worklist after calling
         SimplifyDemandedBits.

      4. Increase GatherAllAliasesMaxDepth from 6 to 18. That number is
         arbitrary, but seems sufficient to not cause regressions in
         tests.

      5. Remove Chain dependencies of Memory operations on CopyfromReg
         nodes as these are captured by data dependence

      6. Forward loads-store values through tokenfactors containing
          {CopyToReg,CopyFromReg} Values.

      7. Peephole to convert buildvector of extract_vector_elt to
         extract_subvector if possible (see
         CodeGen/AArch64/store-merge.ll)

      8. Store merging for the ARM target is restricted to 32-bit as
         some in some contexts invalid 64-bit operations are being
         generated. This can be removed once appropriate checks are
         added.

    This finishes the change Matt Arsenault started in r246307 and
    jyknight's original patch.

    Many tests required some changes as memory operations are now
    reorderable, improving load-store forwarding. One test in
    particular is worth noting:

      CodeGen/PowerPC/ppc64-align-long-double.ll - Improved load-store
      forwarding converts a load-store pair into a parallel store and
      a memory-realized bitcast of the same value. However, because we
      lose the sharing of the explicit and implicit store values we
      must create another local store. A similar transformation
      happens before SelectionDAG as well.

    Reviewers: arsenm, hfinkel, tstellarAMD, jyknight, nhaehnle

llvm-svn: 293184
2017-01-26 16:02:24 +00:00
Diana Picus 278c722e6d [ARM] GlobalISel: Load i1, i8 and i16 args from stack
Add support for loading i1, i8 and i16 arguments from the stack, with or without
the ABI extension flags.

When the ABI extension flags are present, we load a 4-byte value, otherwise we
preserve the size of the load and let the instruction selector replace it with a
LDRB/LDRH. This generates the same thing as DAGISel.

Differential Revision: https://reviews.llvm.org/D27803

llvm-svn: 293163
2017-01-26 09:20:47 +00:00
Tim Northover 470f070b7d SDag: fix how initial loads are formed when splitting vector ops.
Later code expects the vector loads produced to be directly
concatenable, which means we shouldn't pad anything except the last load
produced with UNDEF.

llvm-svn: 293088
2017-01-25 20:58:26 +00:00
Artur Pilipenko 41c0005aa3 [DAGCombiner] Match load by bytes idiom and fold it into a single load. Attempt #2.
The previous patch (https://reviews.llvm.org/rL289538) got reverted because of a bug. Chandler also requested some changes to the algorithm.
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161212/413479.html

This is an updated patch. The key difference is that collectBitProviders (renamed to calculateByteProvider) now collects the origin of one byte, not the whole value. It simplifies the implementation and allows to stop the traversal earlier if we know that the result won't be used.

From the original commit:

Match a pattern where a wide type scalar value is loaded by several narrow loads and combined by shifts and ors. Fold it into a single load or a load and a bswap if the targets supports it.

Assuming little endian target:
  i8 *a = ...
  i32 val = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24)
=>
  i32 val = *((i32)a)

  i8 *a = ...
  i32 val = (a[0] << 24) | (a[1] << 16) | (a[2] << 8) | a[3]
=>
  i32 val = BSWAP(*((i32)a))

This optimization was discussed on llvm-dev some time ago in "Load combine pass" thread. We came to the conclusion that we want to do this transformation late in the pipeline because in presence of atomic loads load widening is irreversible transformation and it might hinder other optimizations.

Eventually we'd like to support folding patterns like this where the offset has a variable and a constant part:
  i32 val = a[i] | (a[i + 1] << 8) | (a[i + 2] << 16) | (a[i + 3] << 24)

Matching the pattern above is easier at SelectionDAG level since address reassociation has already happened and the fact that the loads are adjacent is clear. Understanding that these loads are adjacent at IR level would have involved looking through geps/zexts/adds while looking at the addresses.

The general scheme is to match OR expressions by recursively calculating the origin of individual bytes which constitute the resulting OR value. If all the OR bytes come from memory verify that they are adjacent and match with little or big endian encoding of a wider value. If so and the load of the wider type (and bswap if needed) is allowed by the target generate a load and a bswap if needed.

Reviewed By: RKSimon, filcab, chandlerc 

Differential Revision: https://reviews.llvm.org/D27861

llvm-svn: 293036
2017-01-25 08:53:31 +00:00
Diana Picus d83df5d372 [ARM] GlobalISel: Support i1 add and ABI extensions
Add support for:
* i1 add
* i1 function arguments, if passed through registers
* i1 returns, with ABI signext/zeroext

Differential Revision: https://reviews.llvm.org/D27706

llvm-svn: 293035
2017-01-25 08:47:40 +00:00
Diana Picus 8b6c6bedcb [ARM] GlobalISel: Support i8/i16 ABI extensions
At the moment, this means supporting the signext/zeroext attribute on the return
type of the function. For function arguments, signext/zeroext should be handled
by the caller, so there's nothing for us to do until we start lowering calls.

Note that this does not include support for other extensions (i8 to i16), those
will be added later.

Differential Revision: https://reviews.llvm.org/D27705

llvm-svn: 293034
2017-01-25 08:10:40 +00:00
Javed Absar 00cce41752 [ARM] Classification Improvements to ARM Sched-Models. NFCI.
This is a series of patches to enable adding of machine sched
models for ARM processors easier and compact. They define new
sched-readwrites for groups of ARM instructions. This has been
missing so far, and as a consequence, machine scheduler models
for individual sub-targets have tended to be larger than they
needed to be. 

The current patch focuses on floating-point instructions.

Reviewers: Diana Picus (rovka), Renato Golin (rengolin)

Differential Revision: https://reviews.llvm.org/D28194

llvm-svn: 292825
2017-01-23 20:20:39 +00:00
Sjoerd Meijer 2db2a947f6 [Thumb] Add support for tMUL in the compare instruction peephole optimizer.
We also want to optimise tests like this: return a*b == 0.  The MULS
instruction is flag setting, so we don't need the CMP instruction but can
instead branch on the result of the MULS. The generated instructions sequence
for this example was: MULS, MOVS, MOVS, CMP. The MOVS instruction load the
boolean values resulting from the select instruction, but these MOVS
instructions are flag setting and were thus preventing this optimisation. Now
we first reorder and move the MULS to before the CMP and generate sequence
MOVS, MOVS, MULS, CMP so that the optimisation could trigger. Reordering of the
MULS and MOVS is safe to do because the subsequent MOVS instructions just set
the CPSR register and don't use it, i.e. the CPSR is dead.

Differential Revision: https://reviews.llvm.org/D27990

llvm-svn: 292608
2017-01-20 13:10:12 +00:00
Serge Rogatch f83d2a25bf [XRay][Arm] Repair XRay table emission on Arm32 and add tests to identify such problem earlier
Summary:
Emission of XRay table was occasionally disabled for Arm32, but this bug was not then detected because earlier (also by mistake) testing of XRay was occasionally disabled on 32-bit Arm targets. This patch should fix that problem and detect such problems in the future.
This patch is one of a series, see also
- https://reviews.llvm.org/D28623

Reviewers: rengolin, dberris

Reviewed By: dberris

Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown

Differential Revision: https://reviews.llvm.org/D28624

llvm-svn: 292516
2017-01-19 20:24:23 +00:00
Renato Golin 03c5e69d07 Revert "[XRay][Arm] Repair XRay table emission on Arm32 and add tests to identify such problem earlier"
This reverts commit r292210, as it broke the Thumb buldbot with:

clang-5.0: error: the clang compiler does not support '-fxray-instrument
on thumbv7-unknown-linux-gnueabihf'.

llvm-svn: 292357
2017-01-18 09:08:43 +00:00
Serge Rogatch 50be6b45a9 [XRay][Arm] Repair XRay table emission on Arm32 and add tests to identify such problem earlier
Summary:
Emission of XRay table was occasionally disabled for Arm32, but this bug was not then detected because earlier (also by mistake) testing of XRay was occasionally disabled on 32-bit Arm targets. This patch should fix that problem and detect such problems in the future.
This patch is one of a series, see also
- https://reviews.llvm.org/D28623

Reviewers: rengolin, dberris

Reviewed By: dberris

Subscribers: llvm-commits, aemerson, rengolin, dberris, iid_iunknown

Differential Revision: https://reviews.llvm.org/D28624

llvm-svn: 292210
2017-01-17 11:52:10 +00:00
Simon Pilgrim db73dbcc7c [SelectionDAG] Add support for BITREVERSE constant folding
We were relying on constant folding of the legalized instructions to do what constant folding we had previously

llvm-svn: 292114
2017-01-16 13:39:00 +00:00
Kyle Butt efe56fed12 Revert "CodeGen: Allow small copyable blocks to "break" the CFG."
This reverts commit ada6595a526d71df04988eb0a4b4fe84df398ded.

This needs a simple probability check because there are some cases where it is
not profitable.

llvm-svn: 291695
2017-01-11 19:55:19 +00:00
Eli Friedman 3a03742c37 [ARM] More aggressive matching for vpadd and vpaddl.
The new matchers work after legalization to make them simpler, and to avoid
blocking other optimizations.

Differential Revision: https://reviews.llvm.org/D27779

llvm-svn: 291693
2017-01-11 19:33:38 +00:00
Evgeny Astigeevich 56f5b8931f [ARM] Fix test CodeGen/ARM/fpcmp_ueq.ll broken by rL290616
Commit rL290616 (https://reviews.llvm.org/rL290616) changed a checking command
for the triple arm-apple-darwin in LLVM::CodeGen/ARM/fpcmp_ueq.ll. As a result
of the changes the test could fail for the valid generated code.

These changes fixes the test to check only instructions we would expect.

Differential Revision: https://reviews.llvm.org/D28159

llvm-svn: 291678
2017-01-11 16:23:28 +00:00
Kyle Butt df27aa8c89 CodeGen: Allow small copyable blocks to "break" the CFG.
When choosing the best successor for a block, ordinarily we would have preferred
a block that preserves the CFG unless there is a strong probability the other
direction. For small blocks that can be duplicated we now skip that requirement
as well.

Differential revision: https://reviews.llvm.org/D27742

llvm-svn: 291609
2017-01-10 23:04:30 +00:00
Matt Arsenault 0b382a7cb8 DAG: Avoid OOB when legalizing vector indexing
If a vector index is out of bounds, the result is supposed to be
undefined but is not undefined behavior. Change the legalization
for indexing the vector on the stack so that an out of bounds
index does not create an out of bounds memory access.

llvm-svn: 291604
2017-01-10 22:02:30 +00:00
Joerg Sonnenberger 7b83732a40 Emit .cfi_sections before the first .cfi_startproc
GNU as rejects input where .cfi_sections is used after .cfi_startproc,
if the new section differs from the old. Adjust our output to always
emit .cfi_sections before the first .cfi_startproc to minimize necessary
code.

Differential Revision: https://reviews.llvm.org/D28011

llvm-svn: 290817
2017-01-02 18:05:27 +00:00
Saleem Abdulrasool 0ce0dc250c test: modernise ARM CodeGen tests
Replace the use of grep with FileCheck.  Tidy up some of the tests.  A
few of the tests have been left as weak as previously, though some have
been made more stringent.

llvm-svn: 290616
2016-12-27 18:35:19 +00:00
Zijiao Ma bf6007bd1b Make the canonicalisation on shifts benifit to more case.
1.Fix pessimized case in FIXME.
2.Add tests for it.
3.The canonicalisation on shifts results in different sequence for
  tests of machine-licm.Correct some check lines.

Differential Revision: https://reviews.llvm.org/D27916

llvm-svn: 290410
2016-12-23 02:56:07 +00:00
Adrian Prantl 1eadba1c8c Renumber testcase metadata nodes after r290153.
This patch renumbers the metadata nodes in debug info testcases after
https://reviews.llvm.org/D26769. This is a separate patch because it
causes so much churn. This was implemented with a python script that
pipes the testcases through llvm-as - | llvm-dis - and then goes
through the original and new output side-by side to insert all
comments at a close-enough location.

Differential Revision: https://reviews.llvm.org/D27765

llvm-svn: 290292
2016-12-22 00:45:21 +00:00
Adrian Prantl b767f31290 Legalize metadata in legacy testcases
llvm-svn: 290285
2016-12-21 23:28:49 +00:00
Eli Friedman d03df8145f [ARM] Implement isExtractSubvectorCheap.
See https://reviews.llvm.org/D6678 for the history of
isExtractSubvectorCheap. Essentially the same considerations apply
to ARM.

This temporarily breaks the formation of vpadd/vpaddl in certain cases;
AddCombineToVPADDL essentially assumes that we won't form VUZP shuffles.
See https://reviews.llvm.org/D27779 for followup fix.

Differential Revision: https://reviews.llvm.org/D27774

llvm-svn: 290198
2016-12-20 20:05:07 +00:00
Eli Friedman 7ce3d79986 [ARM] Generate checks for shuffle tests using update_llc_test_checks.py.
llvm-svn: 290196
2016-12-20 19:33:24 +00:00
Adrian Prantl bceaaa9643 [IR] Remove the DIExpression field from DIGlobalVariable.
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.

Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:

(1) The DIGlobalVariable should describe the source level variable,
    not how to get to its location.

(2) It makes it unsafe/hard to update the expressions when we call
    replaceExpression on the DIGLobalVariable.

(3) It makes it impossible to represent a global variable that is in
    more than one location (e.g., a variable with multiple
    DW_OP_LLVM_fragment-s).  We also moved away from attaching the
    DIExpression to DILocalVariable for the same reasons.

This reapplies r289902 with additional testcase upgrades and a change
to the Bitcode record for DIGlobalVariable, that makes upgrading the
old format unambiguous also for variables without DIExpressions.

<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769

llvm-svn: 290153
2016-12-20 02:09:43 +00:00
Eli Friedman 1a9a887a29 Add ARM support to update_llc_test_checks.py
Just the minimal support to get it working at the moment.

Includes checks for test/CodeGen/ARM/vzip.ll as an example.

Differential Revision: https://reviews.llvm.org/D27829

llvm-svn: 290144
2016-12-19 23:09:51 +00:00
Diana Picus 3bae486b7f [ARM] GlobalISel: Add more checks to test
llvm-svn: 290108
2016-12-19 14:08:11 +00:00
Diana Picus 58265c4788 [ARM] GlobalISel: Minor style fixup in test
llvm-svn: 290107
2016-12-19 14:08:06 +00:00
Diana Picus 97ae95c3a8 [ARM] GlobalISel: Lower i8 and i16 register args
This allows lowering i8 and i16 arguments if they can fit in the registers. Note
that the lowering is incomplete - ABI extensions are handled in a subsequent
patch.

(Last part of)
Differential Revision: https://reviews.llvm.org/D27704

llvm-svn: 290106
2016-12-19 14:08:02 +00:00
Diana Picus 5a724452a0 [ARM] GlobalISel: Allow i8 and i16 adds
Teach the instruction selector and legalizer that it's ok to have adds with 8 or
16-bit integers.

This is the second part of https://reviews.llvm.org/D27704

llvm-svn: 290105
2016-12-19 14:07:56 +00:00
Diana Picus 36aa09fa3c [ARM] GlobalISel: Select i8 and i16 copies
Teach the instruction selector that it's ok to copy small values from physical
registers.

First part of https://reviews.llvm.org/D27704

llvm-svn: 290104
2016-12-19 14:07:50 +00:00
Diana Picus 1437f6d710 [ARM] GlobalISel: Lower more than 4 arguments
This adds support for lowering more than 4 arguments (although still i32 only).
It uses the handleAssignments / ValueHandler infrastructure extracted from
the AArch64 backend in r288658.

Differential Revision: https://reviews.llvm.org/D27195

llvm-svn: 290098
2016-12-19 11:55:41 +00:00
Diana Picus 519807f7be [ARM] GlobalISel: Support loading from the stack
Add support for selecting simple G_LOAD and G_FRAME_INDEX instructions (32-bit
scalars only). This will be useful for functions that need to pass arguments on
the stack.

First part of https://reviews.llvm.org/D27195.

llvm-svn: 290096
2016-12-19 11:26:31 +00:00
Matthias Braun 9439d3dc2c Move test to correct directory
See also test/CodeGen/MIR/README

llvm-svn: 290032
2016-12-17 02:16:26 +00:00
Adrian Prantl 73ec065604 Revert "[IR] Remove the DIExpression field from DIGlobalVariable."
This reverts commit 289920 (again).
I forgot to implement a Bitcode upgrade for the case where a DIGlobalVariable
has not DIExpression. Unfortunately it is not possible to safely upgrade
these variables without adding a flag to the bitcode record indicating which
version they are.
My plan of record is to roll the planned follow-up patch that adds a
unit: field to DIGlobalVariable into this patch before recomitting.
This way we only need one Bitcode upgrade for both changes (with a
version flag in the bitcode record to safely distinguish the record
formats).

Sorry for the churn!

llvm-svn: 289982
2016-12-16 19:39:01 +00:00
Eli Friedman f624ec27b7 [ARM] Add ARMISD::VLD1DUP to match vld1_dup more consistently.
Currently, there are substantial problems forming vld1_dup even if the
VDUP survives legalization. The lack of an actual node
leads to terrible results: not only can we not form post-increment vld1_dup
instructions, but we form scalar pre-increment and post-increment
loads which force the loaded value into a GPR. This patch fixes that
by combining the vdup+load into an ARMISD node before DAGCombine
messes it up.

Also includes a crash fix for vld2_dup (see testcase @vld2dupi8_postinc_variable).

Recommiting with fix to avoid forming vld1dup if the type of the load
doesn't match the type of the vdup (see
https://llvm.org/bugs/show_bug.cgi?id=31404).

Differential Revision: https://reviews.llvm.org/D27694

llvm-svn: 289972
2016-12-16 18:44:08 +00:00
Diana Picus 812caee65a [ARM] GlobalISel: Select add i32, i32
Add the minimal support necessary to select a function that returns the sum of
two i32 values.

This includes some support for argument/return lowering of i32 values through
registers, as well as the handling of copy and add instructions throughout the
GlobalISel pipeline.

Differential Revision: https://reviews.llvm.org/D26677

llvm-svn: 289940
2016-12-16 12:54:46 +00:00
Nico Weber 11c2e6ee3a Revert 279703, it caused PR31404.
llvm-svn: 289923
2016-12-16 04:51:25 +00:00
Adrian Prantl 74a835cda0 [IR] Remove the DIExpression field from DIGlobalVariable.
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.

Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:

(1) The DIGlobalVariable should describe the source level variable,
    not how to get to its location.

(2) It makes it unsafe/hard to update the expressions when we call
    replaceExpression on the DIGLobalVariable.

(3) It makes it impossible to represent a global variable that is in
    more than one location (e.g., a variable with multiple
    DW_OP_LLVM_fragment-s).  We also moved away from attaching the
    DIExpression to DILocalVariable for the same reasons.

This reapplies r289902 with additional testcase upgrades.

<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769

llvm-svn: 289920
2016-12-16 04:25:54 +00:00
Chandler Carruth 4154062b69 Revert patch series introducing the DAG combine to match a load-by-bytes
idiom.

r289538: Match load by bytes idiom and fold it into a single load
r289540: Fix a buildbot failure introduced by r289538
r289545: Use more detailed assertion messages in the code ...
r289646: Add a couple of assertions to the load combine code ...

This DAG combine has a bad crash in it that is quite hard to trigger
sadly -- it relies on sneaking code with UB through the SDAG build and
into this particular combine. I've responded to the original commit with
a test case that reproduces it.

However, the code also has other problems that will require substantial
changes to address and so I'm going ahead and reverting it for now. This
should unblock us and perhaps others that are hitting the crash in the
wild and will let a fresh patch with updated approach come in cleanly
afterward.

Sorry for any trouble or disruption!

llvm-svn: 289916
2016-12-16 04:05:22 +00:00
Adrian Prantl 03c6d31a3b Revert "[IR] Remove the DIExpression field from DIGlobalVariable."
This reverts commit 289902 while investigating bot berakage.

llvm-svn: 289906
2016-12-16 01:00:30 +00:00
Adrian Prantl ce13935776 [IR] Remove the DIExpression field from DIGlobalVariable.
This patch implements PR31013 by introducing a
DIGlobalVariableExpression that holds a pair of DIGlobalVariable and
DIExpression.

Currently, DIGlobalVariables holds a DIExpression. This is not the
best way to model this:

(1) The DIGlobalVariable should describe the source level variable,
    not how to get to its location.

(2) It makes it unsafe/hard to update the expressions when we call
    replaceExpression on the DIGLobalVariable.

(3) It makes it impossible to represent a global variable that is in
    more than one location (e.g., a variable with multiple
    DW_OP_LLVM_fragment-s).  We also moved away from attaching the
    DIExpression to DILocalVariable for the same reasons.

<rdar://problem/29250149>
https://llvm.org/bugs/show_bug.cgi?id=31013
Differential Revision: https://reviews.llvm.org/D26769

llvm-svn: 289902
2016-12-16 00:36:43 +00:00
Eli Friedman 379294676d Don't combine splats with other shuffles.
We sometimes end up creating shuffles which are worse than the obvious
translation of the IR.

Fixes https://llvm.org/bugs/show_bug.cgi?id=31301 .

Differential Revision: https://reviews.llvm.org/D27793

llvm-svn: 289882
2016-12-15 22:41:40 +00:00
Eli Friedman 34505083c6 Don't combine a shuffle of two BUILD_VECTORs with duplicate elements.
Targets can't handle this case well in general; we often transform
a shuffle of two cheap BUILD_VECTORs to element-by-element insertion,
which is very inefficient.

Fixes https://llvm.org/bugs/show_bug.cgi?id=31364 . Partially
fixes https://llvm.org/bugs/show_bug.cgi?id=31301.

Differential Revision: https://reviews.llvm.org/D27787

llvm-svn: 289874
2016-12-15 21:36:59 +00:00
Sjoerd Meijer 96e10b5a9e [Thumb] Teach ISel how to lower compares of AND bitmasks efficiently
This is essentially a recommit of r285893, but with a correctness fix. The
problem of the original commit was that this:

bic r5, r7, #31
cbz r5, .LBB2_10

got rewritten into:

lsrs  r5, r7, #5
beq .LBB2_10

The result in destination register r5 is not the same and this is incorrect
when r5 is not dead. So this fix includes checking the uses of the AND
destination register. And also, compared to the original commit, some regression
tests didn't need changing anymore because of this extra check.

For completeness, this was the original commit message:

For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more
efficient instruction selection if the bitmask is one consecutive sequence of
set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).

1) If the bitmask touches the LSB, then we can remove all the upper bits and
set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and
set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit
into the sign bit with one LSLS and change the condition query from NE/EQ to
MI/PL (we could also implement this by shifting into the carry bit and
branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower
zero bits of the mask.

1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two
16-bit instructions but can elide the CMP and doesn't require materializing a
complex immediate, so is also a win.

Differential Revision: https://reviews.llvm.org/D27761

llvm-svn: 289794
2016-12-15 09:38:59 +00:00