Commit Graph

18 Commits

Author SHA1 Message Date
Nirav Dave a81682aad4 Revert "In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled."
This reverts commit r284151 which appears to be triggering a LTO
failures on Hexagon

llvm-svn: 284157
2016-10-13 20:23:25 +00:00
Nirav Dave 4b36957243 In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled.
Retrying after upstream changes.

   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.

    CodeGen/AMDGPU/vgpr-spill-emergency-stack-slot-compute.ll -
      This test appears to work but no longer exhibits the spill behavior.

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: 284151
2016-10-13 19:20:16 +00:00
Nirav Dave e524f50882 Revert "In visitSTORE, always use FindBetterChain, rather than only when UseAA is enabled."
This reverts commit r282600 due to test failues with MCJIT

llvm-svn: 282604
2016-09-28 16:37:50 +00:00
Nirav Dave e17e055b75 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 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.

    CodeGen/AMDGPU/vgpr-spill-emergency-stack-slot-compute.ll -
      This test appears to work but no longer exhibits the spill
      behavior.

Reviewers: arsenm, hfinkel, tstellarAMD, nhaehnle, jyknight

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

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

llvm-svn: 282600
2016-09-28 15:50:43 +00:00
Simon Pilgrim 8ae6dad49b [X86][SSE] Don't decide when to scalarize CTTZ/CTLZ for performance at lowering - this is what cost models are for
Improved CTTZ/CTLZ costings will be added shortly

llvm-svn: 277713
2016-08-04 10:14:39 +00:00
Craig Topper c48c029610 [AVX-512] Fix duplicate column in AVX512 execution dependency table that was preventing VMOVDQU32/VMOVDQA32 from being recognized. Fix a bug in the code that stops execution dependency fix from turning operations on 32-bit integer element types into operations on 64-bit integer element types.
llvm-svn: 277327
2016-08-01 07:55:33 +00:00
Matthias Braun 152e7c8b12 VirtRegMap: Replace some identity copies with KILL instructions.
An identity COPY like this:
   %AL = COPY %AL, %EAX<imp-def>
has no semantic effect, but encodes liveness information: Further users
of %EAX only depend on this instruction even though it does not define
the full register.

Replace the COPY with a KILL instruction in those cases to maintain this
liveness information. (This reverts a small part of r238588 but this
time adds a comment explaining why a KILL instruction is useful).

llvm-svn: 274952
2016-07-09 00:19:07 +00:00
Simon Pilgrim 265995ef53 [X86][SSSE3] Lower vector CTLZ with PSHUFB lookups
This patch uses PSHUFB to lower vector CTLZ and avoid (slower) scalarizations.

The leading zero count of each 4-bit nibble of the vector is determined by using a PSHUFB lookup. Pairs of results are then repeatedly combined up to the original element width.

Differential Revision: http://reviews.llvm.org/D20016

llvm-svn: 269646
2016-05-16 11:19:11 +00:00
Simon Pilgrim 872dd6c3fe [X86][SSE] Added 32-bit tests for vector lzcnt/tzcnt tests
v2i64 tests are particularly bad on 32-bit targets.

llvm-svn: 265789
2016-04-08 15:01:31 +00:00
Simon Pilgrim 0acc32a3b3 [X86][AVX512] Added support for VPMOVZX shuffle decoding.
llvm-svn: 260007
2016-02-06 19:51:21 +00:00
Simon Pilgrim 83e04913e5 [X86][AVX512] Fixed prefix ordering for lzcnt tests.
Let AVX512 targets share the same CHECKs.

llvm-svn: 260000
2016-02-06 18:07:19 +00:00
Elena Demikhovsky db738d9cc3 AVX-512: Optimized SIMD truncate operations for AVX512F set.
Optimized <8 x i32> to <8 x i16>
<4 x i64> to < 4 x i32>
<16 x i16> to <16 x i8>
All these oprtrations use now AVX512F set (KNL). Before this change it was implemented with AVX2 set.


Differential Revision: http://reviews.llvm.org/D14108

llvm-svn: 251764
2015-11-01 11:45:47 +00:00
Igor Breger cbb9550537 AVX512: Lowering i8/i16 vector CTLZ using the dword LZCNT vector instruction
Differential Revision: http://reviews.llvm.org/D13632

llvm-svn: 250649
2015-10-18 09:56:39 +00:00
Simon Pilgrim a1ceba8ab4 [X86] Updated vector lzcnt tests. Added missing vec512 tests.
llvm-svn: 246927
2015-09-05 11:56:30 +00:00
Igor Breger 0dcd8bcf24 AVX512: Implemented encoding and intrinsics for vplzcntq, vplzcntd, vpconflictq, vpconflictd
Added tests for intrinsics and encoding.

Differential Revision: http://reviews.llvm.org/D11931

llvm-svn: 246750
2015-09-03 09:05:31 +00:00
Simon Pilgrim 23a29dafda [X86][SSE] Tidied up vector CTLZ/CTTZ. NFCI.
llvm-svn: 242645
2015-07-19 17:09:43 +00:00
Simon Pilgrim 4af289d0f2 [X86][SSE] Added lzcnt vector tests.
llvm-svn: 239333
2015-06-08 19:58:43 +00:00
Simon Pilgrim 4791f6d89b [DAGCombiner] Added CTLZ vector constant folding support.
llvm-svn: 239305
2015-06-08 16:19:00 +00:00