Commit Graph

1390 Commits

Author SHA1 Message Date
Evandro Menezes 7960b2e19a [AArch64] Generate literals by the little end
ARM seems to prefer that long literals be formed from their little end in
order to promote the fusion of the instrs pairs MOV/MOVK and MOVK/MOVK on
Cortex A57 and others (v.  "Cortex A57 Software Optimisation Guide", section
4.14).

Differential revision: https://reviews.llvm.org/D28697

llvm-svn: 292422
2017-01-18 18:57:08 +00:00
Justin Bogner fde0104649 GlobalISel: Implement narrowing for G_STORE
Legalize stores of types that are too wide by breaking them up into
sequences of smaller stores.

llvm-svn: 292412
2017-01-18 17:29:54 +00:00
Tim Northover 33a1a0b001 GlobalISel: fix comparison order for G_FCMP
As with G_ICMP we'd written the CSET instructions backwards.

llvm-svn: 292285
2017-01-17 23:04:01 +00:00
Tim Northover 509091f9e0 GlobalISel: add callseq instructions to record stack usage
llvm-svn: 292284
2017-01-17 22:43:34 +00:00
Tim Northover d943354216 GlobalISel: correctly handle varargs
Some platforms (notably iOS) use a different calling convention for unnamed vs
named parameters in varargs functions, so we need to keep track of this
information when translating calls.

Since not many platforms are involved, the guts of the special handling is in
the ValueHandler class (with a generic implementation that should work for most
targets).

llvm-svn: 292283
2017-01-17 22:30:10 +00:00
Tim Northover b6636fd392 [GlobalISel] track predecessor mapping during switch lowering.
Correctly populating Machine PHIs relies on knowing exactly how the IR level
CFG was lowered to MachineIR. This needs to be tracked by any translation
phases that meddle (currently only SwitchInst handling).

This reapplies r291973 which was reverted because of testing failures. Fixes:

 + Don't return an ArrayRef to a local temporary.
 + Incorporate Kristof's suggested comment improvements.

llvm-svn: 292278
2017-01-17 22:13:50 +00:00
Chad Rosier 58fb5f5e58 [AArch64] Falkor supports Rounding Double Multiply Add/Subtract instructions.
Falkor only partially implements the ARMv8.1a extensions, so this patch
refactors the support for the SQRDML[A|S]H instruction into a separate
feature.

Differential Revision: https://reviews.llvm.org/D28681

llvm-svn: 292142
2017-01-16 16:28:43 +00:00
Daniel Jasper bf56ad36cb Revert "[GlobalISel] track predecessor mapping during switch lowering."
This reverts commit r291973.

The test fails in a Release build with LLVM_BUILD_GLOBAL_ISEL enabled.
AFAICT, llc segfaults. I'll add a few more details to the original
commit.

llvm-svn: 292061
2017-01-15 09:41:49 +00:00
Tim Northover 2b57987827 [GlobalISel] track predecessor mapping during switch lowering.
Correctly populating Machine PHIs relies on knowing exactly how the IR level
CFG was lowered to MachineIR. This needs to be tracked by any translation
phases that meddle (currently only SwitchInst handling).

llvm-svn: 291973
2017-01-13 23:11:37 +00:00
James Y Knight 99a2ce2af2 Check for register clobbers when merging a vreg live range with a
reserved physreg in RegisterCoalescer.

Previously, we only checked for clobbers when merging into a READ of
the physreg, but not when merging from a WRITE to the physreg.

Differential Revision: https://reviews.llvm.org/D28527

llvm-svn: 291942
2017-01-13 19:08:36 +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
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
Chad Rosier 3daffbf6a8 [AArch64] Add support for lowering bitreverse to the rbit instruction.
Differential Revision: https://reviews.llvm.org/D28379

llvm-svn: 291575
2017-01-10 17:20:33 +00:00
Matthias Braun 258b847c4f AArch64CollectLOH: Rewrite as block-local analysis.
Re-apply r288561: This time with a fix where the ADDs that are part of a
3 instruction LOH would not invalidate the "LastAdrp" state. This fixes
http://llvm.org/PR31361

Previously this pass was using up to 5% compile time in some cases which
is a bit much for what it is doing. The pass featured a full blown
data-flow analysis which in the default configuration was restricted to a
single block.

This rewrites the pass under the assumption that we only ever work on a
single block. This is done in a single pass maintaining a state machine
per general purpose register to catch LOH patterns.

Differential Revision: https://reviews.llvm.org/D27329

This reverts commit 9e6cedb0a4f14364d6511597a9160305e7d34493.

llvm-svn: 291266
2017-01-06 19:22:01 +00:00
Matthias Braun 1172332203 CodeGen: Assert that liveness is up to date when reading block live-ins.
Add an assert that checks whether liveins are up to date before they are
used.

- Do not print liveins into .mir files anymore in situations where they
  are out of date anyway.
- The assert in the RegisterScavenger is superseded by the new one in
  livein_begin().
- Skip parts of the liveness updating logic in IfConversion.cpp when
  liveness isn't tracked anymore (just enough to avoid hitting the new
  assert()).

Differential Revision: https://reviews.llvm.org/D27562

llvm-svn: 291169
2017-01-05 20:01:19 +00:00
Kristof Beyls a983e7c4a4 [GlobalISel] Add support for address-taken basic blocks
To make this work, pointers from the MachineBasicBlock to the LLVM-IR-level
basic blocks need to be initialized, as the AsmPrinter uses this link to be
able to print out labels for the basic blocks that are address-taken.

Most of the changes in this commit are about adapting existing tests to include
the basic block name that is now printed out in the MIR format, now that the
name becomes available as the link to the LLVM-IR basic block is initialized.
The relevant test change for the functionality added in this patch are the
added "(address-taken)" strings in
test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll.

Differential Revision: https://reviews.llvm.org/D28123

llvm-svn: 291105
2017-01-05 13:27:52 +00:00
Kristof Beyls eced071e88 [GlobalISel] Add support for switch statements
This commit does this using a trivial chain of conditional branches.  In the
future, we probably want to reuse the optimized switch lowering used in
SelectionDAG.

Differential Revision: https://reviews.llvm.org/D28176

llvm-svn: 291099
2017-01-05 11:28:51 +00:00
Kristof Beyls 2252440b81 [GlobalISel] Fix AArch64 ICMP instruction selection
Differential Revision: https://reviews.llvm.org/D28175

llvm-svn: 291097
2017-01-05 10:16:08 +00:00
Tim Shen 5480eb8445 [Legalizer] Fix fp-to-uint to fp-tosint promotion assertion.
Summary:
When promoting fp-to-uint16 to fp-to-sint32, the result is actually zero
extended. For example, given double 65534.0, without legalization:

  fp-to-uint16: 65534.0 -> 0xfffe

With the legalization:

  fp-to-sint32: 65534.0 -> 0x0000fffe

Without this patch, legalization wrongly emits a signed extend assertion,
which is consumed by later icmp instruction, and cause miscompile.

Note that the floating point value must be in [0, 65535), otherwise the
behavior is undefined.

This patch reverts r279223 behavior and adds more tests and
documentations.

In PR29041's context, James Molloy mentioned that:

  We don't need to mask because conversion from float->uint8_t is
  undefined if the integer part of the float value is not representable in
  uint8_t. Therefore we can assume this doesn't happen!

which is totally true and good, because fptoui is documented clearly to
have undefined behavior when overflow/underflow happens. We should take
the advantage of this behavior so that we can save unnecessary mask
instructions.

Reviewers: jmolloy, nadav, echristo, kbarton

Subscribers: mehdi_amini, nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D28284

llvm-svn: 291015
2017-01-04 22:11:42 +00:00
Chad Rosier 63687e40bc [AArch64] Update the feature set for Qualcomm's Falkor CPU.
llvm-svn: 291010
2017-01-04 21:26:23 +00:00
Nirav Dave 0f9d111f97 [AArch64] Fix over-eager early-exit in load-store combiner
Fix early-exit analysis for memory operation pairing when operations are
not emitted in ascending order.

Reviewers: mcrosier, t.p.northover

Subscribers: aemerson, rengolin, llvm-commits

Differential Revision: https://reviews.llvm.org/D28251

llvm-svn: 291008
2017-01-04 21:21:46 +00:00
Ahmed Bougacha 1277833aa6 [AArch64] Simplify indexed-memory testcase. NFC.
We're only testing the addressing mode on the stores; we don't
need to load/store pointers we can simply pass/return.

llvm-svn: 290385
2016-12-22 22:27:05 +00:00
Quentin Colombet f372150f73 [AArch64] Change a test to use a generic instr instead of a target specific one.
Target specific instructions have requirements that are not compatible
with what we want to test here. Namely, target specific instructions
must have their operands properly mapped on register classes.

llvm-svn: 290379
2016-12-22 21:56:37 +00:00
Quentin Colombet f38015e5fe [AArch64][CallLowering] Constraint registers on target specific instruction
The InstructionSelect pass will not look at target specific instructions
since they are already selected. As a result, the operands of target
specific instructions must be properly constrained, because it is not
going to fix them.

This fixes invalid register classes on call instruction.

llvm-svn: 290377
2016-12-22 21:56:31 +00:00
Haicheng Wu 9ac20a1e10 [AArch64] Correct the check of signed 9-bit imm in getIndexedAddressParts().
-256 is a legal indexed address part.

Differential Revision: https://reviews.llvm.org/D27537

llvm-svn: 290296
2016-12-22 01:39:24 +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
Sebastian Pop 1857800cb5 remove pretty-print test that requires debug
There is no need to test the pretty printer. Remove the boggus test to make the
build bots happy.

llvm-svn: 290234
2016-12-21 03:37:39 +00:00
Sebastian Pop 7779484313 machine combiner: fix pretty printer
we used to print UNKNOWN instructions when the instruction to be printer was not
yet inserted in any BB: in that case the pretty printer would not be able to
compute a TII as the instruction does not belong to any BB or function yet.
This patch explicitly passes the TII to the pretty-printer.

Differential Revision: https://reviews.llvm.org/D27645

llvm-svn: 290228
2016-12-21 01:41:12 +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
Matthias Braun 15b56e6973 Revert "AArch64CollectLOH: Rewrite as block-local analysis."
It is still breaking Chrome. http://llvm.org/PR31361

This reverts commit r290026.

llvm-svn: 290047
2016-12-17 18:53:11 +00:00
Matthias Braun e813cf457a AArch64CollectLOH: Rewrite as block-local analysis.
Re-apply r288561: Liveness tracking should be correct now after r290014.

Previously this pass was using up to 5% compile time in some cases which
is a bit much for what it is doing. The pass featured a full blown
data-flow analysis which in the default configuration was restricted to a
single block.

This rewrites the pass under the assumption that we only ever work on a
single block. This is done in a single pass maintaining a state machine
per general purpose register to catch LOH patterns.

Differential Revision: https://reviews.llvm.org/D27329

llvm-svn: 290026
2016-12-17 01:15:59 +00:00
Matthias Braun 76bb4139dc AArch64: Enable post-ra liveness updates
Differential Revision: https://reviews.llvm.org/D27559

llvm-svn: 290014
2016-12-16 23:55:43 +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
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
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
Quentin Colombet 327f942876 [IRTranslator] Merge the entry and ABI lowering blocks.
The IRTranslator uses an additional block before the LLVM-IR entry block
to perform all the ABI lowering and the constant hoisting. Thus, this
block is the actual entry block and it falls through the LLVM-IR entry
block. However, with such representation, we end up with two basic
blocks that are not maximal.

Therefore, this patch adds a bit of canonicalization by merging both the
LLVM-IR entry block and the ABI lowering/constants hoisting into one
block, making the resulting block more likely to be maximal (indeed the
LLVM-IR entry block might not have been maximal).

llvm-svn: 289891
2016-12-15 23:32:25 +00:00
Sanjay Patel afee21a5b2 [DAG] allow more select folding for targets that have 'and not' (PR31175)
The original motivation for this patch comes from wanting to canonicalize 
more IR to selects and also canonicalizing min/max.

If we're going to do that, we need more backend fixups to undo select codegen 
when simpler ops will do. I chose AArch64 for the tests because that shows the
difference in the simplest way. This should fix:
https://llvm.org/bugs/show_bug.cgi?id=31175

Differential Revision: https://reviews.llvm.org/D27489

llvm-svn: 289738
2016-12-14 22:59:14 +00:00
Nirav Dave f5bf03c7ef Revert "In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled."
Reverting due to ARM MCJIT and MIPS LLD error.

This reverts commit r289659.

llvm-svn: 289667
2016-12-14 16:43:44 +00:00
Nirav Dave 8527ab0ad2 In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled.
Retrying after fixing after removing load-store factoring through
token factors in favor of improved token factor operand pruning

Simplify Consecutive Merge Store Candidate Search

Now that address aliasing is much less conservative, push through
simplified store merging search 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.

Whem 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 generally the output CodeGen (with some
exceptions).

Additional Minor Changes:

   1. Finishes removing unused AliasLoad code
   2. Unifies the 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 seemed sufficient to not cause regressions in
      tests.

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. Some tests relying on the order were changed to use
volatile memory operations

Noteworthy tests:

    CodeGen/AArch64/argument-blocks.ll -
      It's not entirely clear what the test_varargs_stackalign test is
      supposed to be asserting, but the new code looks right.

    CodeGen/AArch64/arm64-memset-inline.lli -
    CodeGen/AArch64/arm64-stur.ll -
    CodeGen/ARM/memset-inline.ll -

      The backend now generates *worse* code due to store merging
      succeeding, as we do do a 16-byte constant-zero store efficiently.

    CodeGen/AArch64/merge-store.ll -
      Improved, but there still seems to be an extraneous vector insert
      from an element to itself?

    CodeGen/PowerPC/ppc64-align-long-double.ll -
      Worse code emitted in this case, due to the improved store->load
      forwarding.

    CodeGen/X86/dag-merge-fast-accesses.ll -
    CodeGen/X86/MergeConsecutiveStores.ll -
    CodeGen/X86/stores-merging.ll -
    CodeGen/Mips/load-store-left-right.ll -
      Restored correct merging of non-aligned stores

    CodeGen/AMDGPU/promote-alloca-stored-pointer-value.ll -
      Improved. Correctly merges buffer_store_dword calls

    CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll -
      Improved. Sidesteps loading a stored value and
      merges two stores

    CodeGen/X86/pr18023.ll -
      This test has been removed, as it was asserting incorrect
      behavior. Non-volatile stores *CAN* be moved past volatile loads,
      and now are.

    CodeGen/X86/vector-idiv.ll -
    CodeGen/X86/vector-lzcnt-128.ll -
      It's basically impossible to tell what these tests are actually
      testing. But, looks like the code got better due to the memory
      operations being recognized as non-aliasing.

    CodeGen/X86/win32-eh.ll -
      Both loads of the securitycookie are now merged.

Reviewers: arsenm, hfinkel, tstellarAMD, jyknight, nhaehnle

Subscribers: wdng, nhaehnle, nemanjai, arsenm, weimingz, niravd, RKSimon, aemerson, qcolombet, dsanders, resistor, tstellarAMD, t.p.northover, spatel

Differential Revision: https://reviews.llvm.org/D14834

llvm-svn: 289659
2016-12-14 15:44:26 +00:00
Evandro Menezes aeec780e42 Add support for Samsung Exynos M3 (NFC)
llvm-svn: 289613
2016-12-13 23:31:41 +00:00
Alina Sbirlea 77c5eaaeda Generalize strided store pattern in interleave access pass
Summary:
This patch aims to generalize matching of the strided store accesses to more general masks.
The more general rule is to have consecutive accesses based on the stride:
[x, y, ... z, x+1, y+1, ...z+1, x+2, y+2, ...z+2, ...]
All elements in the masks need not form a contiguous space, there may be gaps.
As before, undefs are allowed and filled in with adjacent element loads.

Reviewers: HaoLiu, mssimpso

Subscribers: mkuper, delena, llvm-commits

Differential Revision: https://reviews.llvm.org/D23646

llvm-svn: 289573
2016-12-13 19:32:36 +00:00
Matthias Braun fde00fc252 Revert "AArch64CollectLOH: Rewrite as block-local analysis."
This is not always behaving as expected as it turns out block live-in
lists are only correct most of the time. Still waiting for reviews on
https://reviews.llvm.org/D27559 to have them correct all of the time.

See also http://llvm.org/PR31361, rdar://25117107

This reverts commit r288567.
This reverts commit r288561.

llvm-svn: 289570
2016-12-13 19:08:17 +00:00
Tim Northover fe7c59adb8 GlobalISel: fix GOT accesses on AArch64.
We were using the correct pseudo-instruction, but because the operand's flags
weren't set correctly we still ended up emitting incorrect relocations during
MC lowering.

llvm-svn: 289566
2016-12-13 18:25:38 +00:00
Sebastian Pop e08d9c7c87 instr-combiner: sum up all latencies of the transformed instructions
We have found that -- when the selected subarchitecture has a scheduling model
and we are not optimizing for size -- the machine-instruction combiner uses a
too-simple algorithm to compute the cost of one of the two alternatives [before
and after running a combining pass on a section of code], and therefor it throws
away the combination results too often.

This fix has the potential to help any ISA with the potential to combine
instructions and for which at least one subarchitecture has a scheduling model.
As of now, this is only known to definitely affect AArch64 subarchitectures with
a scheduling model.

Regression tested on AMD64/GNU-Linux, new test case tested to fail on an
unpatched compiler and pass on a patched compiler.

Patch by Abe Skolnik and Sebastian Pop.

llvm-svn: 289399
2016-12-11 19:39:32 +00:00
Matthias Braun 2c7d52a540 Move .mir tests to appropriate directories
test/CodeGen/MIR should contain tests that intent to test the MIR
printing or parsing. Tests that test something else should be in
test/CodeGen/TargetName even when they are written in .mir.

As a rule of thumb, only tests using "llc -run-pass none" should be in
test/CodeGen/MIR.

llvm-svn: 289254
2016-12-09 19:08:15 +00:00
Nirav Dave bedb5d906c Revert "In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled."
This reverts commit r289221 which appears to be triggering an assertion

llvm-svn: 289226
2016-12-09 17:18:24 +00:00
Nirav Dave fd51ff4fd8 In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled.
Retrying after fixing overly aggressive load-store forwarding optimization.

Simplify Consecutive Merge Store Candidate Search

Now that address aliasing is much less conservative, push through
simplified store merging search 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.

Whem 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 generally the output CodeGen (with some
exceptions).

Additional Minor Changes:

   1. Finishes removing unused AliasLoad code
   2. Unifies the 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 seemed sufficient to not cause regressions in
      tests.

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. Some tests relying on the order were changed to use
volatile memory operations

Noteworthy tests:

    CodeGen/AArch64/argument-blocks.ll -
      It's not entirely clear what the test_varargs_stackalign test is
      supposed to be asserting, but the new code looks right.

    CodeGen/AArch64/arm64-memset-inline.lli -
    CodeGen/AArch64/arm64-stur.ll -
    CodeGen/ARM/memset-inline.ll -

      The backend now generates *worse* code due to store merging
      succeeding, as we do do a 16-byte constant-zero store efficiently.

    CodeGen/AArch64/merge-store.ll -
      Improved, but there still seems to be an extraneous vector insert
      from an element to itself?

    CodeGen/PowerPC/ppc64-align-long-double.ll -
      Worse code emitted in this case, due to the improved store->load
      forwarding.

    CodeGen/X86/dag-merge-fast-accesses.ll -
    CodeGen/X86/MergeConsecutiveStores.ll -
    CodeGen/X86/stores-merging.ll -
    CodeGen/Mips/load-store-left-right.ll -
      Restored correct merging of non-aligned stores

    CodeGen/AMDGPU/promote-alloca-stored-pointer-value.ll -
      Improved. Correctly merges buffer_store_dword calls

    CodeGen/AMDGPU/si-triv-disjoint-mem-access.ll -
      Improved. Sidesteps loading a stored value and
      merges two stores

    CodeGen/X86/pr18023.ll -
      This test has been removed, as it was asserting incorrect
      behavior. Non-volatile stores *CAN* be moved past volatile loads,
      and now are.

    CodeGen/X86/vector-idiv.ll -
    CodeGen/X86/vector-lzcnt-128.ll -
      It's basically impossible to tell what these tests are actually
      testing. But, looks like the code got better due to the memory
      operations being recognized as non-aliasing.

    CodeGen/X86/win32-eh.ll -
      Both loads of the securitycookie are now merged.

Reviewers: arsenm, hfinkel, tstellarAMD, jyknight, nhaehnle

Subscribers: wdng, nhaehnle, nemanjai, arsenm, weimingz, niravd, RKSimon, aemerson, qcolombet, dsanders, resistor, tstellarAMD, t.p.northover, spatel

Differential Revision: https://reviews.llvm.org/D14834

llvm-svn: 289221
2016-12-09 16:15:12 +00:00