Commit Graph

1715 Commits

Author SHA1 Message Date
John Brawn 150addb45c [DAGCombiner] Fix infinite loop in vector mul/shl combining
We have the following DAGCombiner transformations:
 (mul (shl X, c1), c2) -> (mul X, c2 << c1)
 (mul (shl X, C), Y) -> (shl (mul X, Y), C)
 (shl (mul x, c1), c2) -> (mul x, c1 << c2)
Usually the constant shift is optimised by SelectionDAG::getNode when it is
constructed, by SelectionDAG::FoldConstantArithmetic, but when we're dealing
with vectors and one of those vector constants contains an undef element
FoldConstantArithmetic does not fold and we enter an infinite loop.

Fix this by making FoldConstantArithmetic use getNode to decide how to fold each
vector element, the same as FoldConstantVectorArithmetic does, and rather than
adding the constant shift to the work list instead only apply the transformation
if it's already been folded into a constant, as if it's not we're going to loop
endlessly. Additionally add missing NoOpaques to one of those transformations,
which I noticed when writing the tests for this.

Differential Revision: https://reviews.llvm.org/D26605

llvm-svn: 287766
2016-11-23 16:05:51 +00:00
Elena Demikhovsky 09375d98b8 Type legalization for compressstore and expandload intrinsics.
Implemented widening (v2f32) and splitting (v16f64).
On splitting, I use "popcnt" to calculate memory increment. 
More type legalization work will come in the next patches.

llvm-svn: 287761
2016-11-23 13:58:24 +00:00
Simon Pilgrim 7a6b6d5656 Fix spelling mistakes in SelectionDAG comments. NFC.
Identified by Pedro Giffuni in PR27636.

llvm-svn: 287487
2016-11-20 13:14:57 +00:00
Asaf Badouh b573553424 DAGCombiner: fix combine of trunc and select
bugzilla:
https://llvm.org/bugs/show_bug.cgi?id=29002
pr29002

Differential Revision: https://reviews.llvm.org/D26449


 

llvm-svn: 286938
2016-11-15 07:55:22 +00:00
Evandro Menezes 21f9ce1a0d [DAG Combiner] Fix the native computation of the Newton series for reciprocals
The generic infrastructure to compute the Newton series for reciprocal and
reciprocal square root was conceived to allow a target to compute the series
itself.  However, the original code did not properly consider this condition
if returned by a target.  This patch addresses the issues to allow a target
to compute the series on its own.

Differential revision: https://reviews.llvm.org/D22975

llvm-svn: 286523
2016-11-10 23:31:06 +00:00
Simon Pilgrim 33fef8e865 Use common SDLoc. NFCI.
llvm-svn: 286473
2016-11-10 16:47:09 +00:00
Simon Pilgrim 37c9034bd6 [DAGCombiner] Correctly extract the ConstOrConstSplat shift value for SHL nodes
We were failing to extract a constant splat shift value if the shifted value was being masked.

The (shl (and (setcc) N01CV) N1CV) -> (and (setcc) N01CV<<N1CV) combine was unnecessarily preventing this.

llvm-svn: 286454
2016-11-10 14:35:09 +00:00
Nicolai Haehnle bea772c6dc DAGCombiner: fix use-after-free when merging consecutive stores
Summary:
Have MergeConsecutiveStores explicitly return information about the stores
that were merged, so that we can safely determine whether the starting
node has been freed.

Reviewers: chandlerc, bogner, niravd

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25601

llvm-svn: 285916
2016-11-03 14:25:04 +00:00
Elena Demikhovsky caaceef4b3 Expandload and Compressstore intrinsics
2 new intrinsics covering AVX-512 compress/expand functionality.
This implementation includes syntax, DAG builder, operation lowering and tests.
Does not include: handling of illegal data types, codegen prepare pass and the cost model.

llvm-svn: 285876
2016-11-03 03:23:55 +00:00
Sanjay Patel 339a51ac13 [DAG] x | x --> x
llvm-svn: 285522
2016-10-30 18:19:35 +00:00
Sanjay Patel 13aee345ca [DAG] x & x --> x
llvm-svn: 285521
2016-10-30 18:13:30 +00:00
Davide Italiano 86168b23cf [DAGCombiner] Fix a crash visiting `AND` nodes.
Instead of asserting that the shift count is != 0 we just bail out
as it's not profitable trying to optimize a node which will be
removed anyway.

Differential Revision:  https://reviews.llvm.org/D26098

llvm-svn: 285480
2016-10-28 23:55:32 +00:00
Simon Pilgrim de86241a09 [DAGCombiner] Enable (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1)) combine for splatted vectors
llvm-svn: 285129
2016-10-25 22:01:09 +00:00
Simon Pilgrim f534573e8c [DAGCombiner] Enable srem(x.y) -> urem(x,y) combine for vectors
SelectionDAG::SignBitIsZero (via SelectionDAG::computeKnownBits) has supported vectors since rL280927

llvm-svn: 285123
2016-10-25 21:20:18 +00:00
Simon Pilgrim 4ebb04510a [DAGCombiner] Enable sdiv(x.y) -> udiv(x,y) combine for vectors
SelectionDAG::SignBitIsZero (via SelectionDAG::computeKnownBits) has supported vectors since rL280927

llvm-svn: 285118
2016-10-25 20:56:42 +00:00
Zvi Rackover 124470a202 [DAGCombine] Preserve shuffles when one of the vector operands is constant
Summary:
Do *not* perform combines such as:

    vector_shuffle<4,1,2,3>(build_vector(Ud, C0, C1 C2), scalar_to_vector(X))
    ->
    build_vector(X, C0, C1, C2)

Keeping the shuffle allows lowering the constant build_vector to a materialized
constant vector (such as a vector-load from the constant-pool or some other idiom).

Reviewers: delena, igorb, spatel, mkuper, andreadb, RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D25524

llvm-svn: 285063
2016-10-25 12:14:19 +00:00
Simon Pilgrim d06641d3dc Use SDValue::getConstantOperandVal() helper. NFCI.
llvm-svn: 284949
2016-10-23 20:17:21 +00:00
Sanjay Patel 81029f6a76 [DAG] fold negation of sign-bit
0 - X --> 0, if the sub is NUW
0 - X --> 0, if X is 0 or the minimum signed value and the sub is NSW
0 - X --> X, if X is 0 or the minimum signed value

This is the DAG equivalent of:
https://reviews.llvm.org/rL284649

plus the fold for the NUW case which already existed in InstSimplify.

Note that we miss a vector fold because of a deficiency in the DAG version of
computeKnownBits().

llvm-svn: 284844
2016-10-21 17:24:26 +00:00
Sanjay Patel cbaba93ce8 [DAG] use SDNode flags 'nsz' to enable fadd/fsub with zero folds
As discussed in D24815, let's start the process of killing off the broken fast-math global
state housed in TargetOptions and eliminate the need for function-level fast-math attributes.

Here we enable two similar folds that are possible when we don't care about signed-zero:
fadd nsz x, 0 --> x
fsub nsz 0, x --> -x

Note that although the test cases include a 'sin' function call, I'm side-stepping the 
FMF-on-calls question (and lack of support in the DAG) for now. It's not needed for these
tests - isNegatibleForFree/GetNegatedExpression just look through a ISD::FSIN node.

Also, when we create an FNEG node and propagate the Flags of the FSUB to it, this doesn't
actually do anything today because Flags are silently dropped for any node that is not a
binary operator.

Differential Revision: https://reviews.llvm.org/D25297

llvm-svn: 284824
2016-10-21 14:36:58 +00:00
Sanjay Patel 0051efcf97 [Target] remove TargetRecip class; 2nd try
This is a retry of r284495 which was reverted at r284513 due to use-after-scope bugs
caused by faulty usage of StringRef.

This version also renames a pair of functions:
getRecipEstimateDivEnabled()
getRecipEstimateSqrtEnabled()
as suggested by Eric Christopher.

original commit msg:

[Target] remove TargetRecip class; move reciprocal estimate isel functionality to TargetLowering

This is a follow-up to https://reviews.llvm.org/D24816 - where we changed reciprocal estimates to be function attributes
rather than TargetOptions.

This patch is intended to be a structural, but not functional change. By moving all of the
TargetRecip functionality into TargetLowering, we can remove all of the reciprocal estimate
state, shield the callers from the string format implementation, and simplify/localize the
logic needed for a target to enable this.

If a function has a "reciprocal-estimates" attribute, those settings may override the target's
default reciprocal preferences for whatever operation and data type we're trying to optimize.
If there's no attribute string or specific setting for the op/type pair, just use the target
default settings.

As noted earlier, a better solution would be to move the reciprocal estimate settings to IR
instructions and SDNodes rather than function attributes, but that's a multi-step job that
requires infrastructure improvements. I intend to work on that, but it's not clear how long
it will take to get all the pieces in place.

Differential Revision: https://reviews.llvm.org/D25440

llvm-svn: 284746
2016-10-20 16:55:45 +00:00
Simon Pilgrim 618d3aedaf [DAGCombiner] Add general constant vector support to (srl (shl x, c), c) -> (and x, cst2)
We already supported scalar constant / splatted constant vector - now accepts any (non opaque) constant scalar / vector

llvm-svn: 284717
2016-10-20 11:10:21 +00:00
Simon Pilgrim e32d0f8413 Merged nested ifs. NFCI.
llvm-svn: 284616
2016-10-19 17:30:24 +00:00
Simon Pilgrim a20aeea998 [DAGCombiner] Add general constant vector support to (shl (add x, c1), c2) -> (add (shl x, c2), c1 << c2)
We already supported scalar constant / splatted constant vector - now accepts any (non opaque) constant scalar / vector

llvm-svn: 284613
2016-10-19 17:12:22 +00:00
Simon Pilgrim 4554e161be [DAGCombiner] Add general constant vector support to (shl (sra x, c1), c1) -> (and x, (shl -1, c1))
We already supported scalar constant / splatted constant vector - now accepts any (non opaque) constant scalar / vector

llvm-svn: 284608
2016-10-19 16:15:30 +00:00
Simon Pilgrim c2e9724909 [DAGCombiner] Add general constant vector support to (shl (mul x, c1), c2) -> (mul x, c1 << c2)
We already supported scalar constant / splatted constant vector - now accepts any (non opaque) constant scalar / vector

llvm-svn: 284607
2016-10-19 15:59:28 +00:00
Simon Pilgrim 7dcb6e572e [DAGCombiner] Just call isConstOrConstSplat directly. NFCI.
This will get the same ConstantSDNode scalar or vector splat value as the current separate dyn_cast<ConstantSDNode> / isVector() approach.

llvm-svn: 284578
2016-10-19 11:28:15 +00:00
Simon Pilgrim b2ca2505cc [DAGCombine] Generalize distributeTruncateThroughAnd to work with any non-opaque constant or constant vector
llvm-svn: 284574
2016-10-19 08:57:37 +00:00
Sanjay Patel 19601fa587 revert r284495: [Target] remove TargetRecip class
There's something wrong with the StringRef usage while parsing the attribute string.

llvm-svn: 284513
2016-10-18 18:36:49 +00:00
Sanjay Patel 08fff9ca81 [Target] remove TargetRecip class; move reciprocal estimate isel functionality to TargetLowering
This is a follow-up to D24816 - where we changed reciprocal estimates to be function attributes
rather than TargetOptions.

This patch is intended to be a structural, but not functional change. By moving all of the
TargetRecip functionality into TargetLowering, we can remove all of the reciprocal estimate
state, shield the callers from the string format implementation, and simplify/localize the
logic needed for a target to enable this.

If a function has a "reciprocal-estimates" attribute, those settings may override the target's
default reciprocal preferences for whatever operation and data type we're trying to optimize.
If there's no attribute string or specific setting for the op/type pair, just use the target
default settings.

As noted earlier, a better solution would be to move the reciprocal estimate settings to IR
instructions and SDNodes rather than function attributes, but that's a multi-step job that
requires infrastructure improvements. I intend to work on that, but it's not clear how long
it will take to get all the pieces in place.

Differential Revision: https://reviews.llvm.org/D25440

llvm-svn: 284495
2016-10-18 17:05:05 +00:00
Simon Pilgrim 25e9628978 [DAGCombiner] Add splatted vector support to (udiv x, (shl pow2, y)) -> x >>u (log2(pow2)+y)
llvm-svn: 284491
2016-10-18 16:36:00 +00:00
Simon Pilgrim 65e0c73875 Strip trailing whitespace (NFCI)
llvm-svn: 284478
2016-10-18 13:44:00 +00:00
Sanjay Patel a7cab58055 [DAG] make isConstOrConstSplat and isConstOrConstSplatFP more accessible; NFC
As noted in:
https://reviews.llvm.org/D25685

This is the next-to-smallest step needed to enable the ComputeNumSignBits fix in that patch. 
In a minor attempt to keep some structure, we're pulling the FP helper over along with its
integer sibling, but clearly we can and should do more refactoring of the similar helper
functions in DAGCombiner and SelectionDAG to simplify and not duplicate functionality.

llvm-svn: 284421
2016-10-17 20:26:46 +00:00
Sanjay Patel 2cf6bfaf73 [DAG] optimize away an arithmetic-right-shift of a 0 or -1 value
This came up as part of:
https://reviews.llvm.org/D25485

Note that the vector case is missed because ComputeNumSignBits() is deficient for vectors.

llvm-svn: 284395
2016-10-17 15:58:28 +00:00
Sanjay Patel 72b5ff646d [DAG] avoid creating illegal node when transforming negated shifted sign bit
Eli noted this potential bug in the post-commit thread for:
https://reviews.llvm.org/rL284239
...but I'm not sure how to trigger it, so there's no test case yet.

llvm-svn: 284268
2016-10-14 19:46:31 +00:00
Sanjay Patel 00fc7a6159 [DAG] add folds for negated shifted sign bit
The same folds exist in InstCombine already.

This came up as part of:
https://reviews.llvm.org/D25485

llvm-svn: 284239
2016-10-14 14:26:47 +00:00
Nicolai Haehnle 86e72d98dd Fix use-after-frees
Extracted from D25313, as suggested by Justin Bogner.

llvm-svn: 284220
2016-10-14 09:49:51 +00:00
Craig Topper 40feb7f157 [DAGCombiner] Teach createBuildVecShuffle to handle cases where input vectors are less than half of the output vector size.
This will be needed by a future commit to support sign/zero extending from v8i8 to v8i64 which requires a sign/zero_extend_vector_inreg to be created which requires v8i8 to be concatenated upto v64i8 and goes through this code.

llvm-svn: 284204
2016-10-14 06:00:42 +00:00
Sanjay Patel 98d0ea64ca [DAG] hoist DL(N) and fix formatting; NFC
llvm-svn: 284170
2016-10-13 22:27:10 +00:00
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
Simon Pilgrim cb59b5257c [DAGCombiner] Add vector support to (mul (shl X, Y), Z) -> (shl (mul X, Z), Y) style combines
llvm-svn: 284122
2016-10-13 14:04:35 +00:00
Simon Pilgrim fa8fadc0e5 [DAGCombiner] Add vector support to C2-(A+C1) -> (C2-C1)-A folding
llvm-svn: 284117
2016-10-13 12:49:31 +00:00
Simon Pilgrim 833b8a2071 [DAGCombiner] Add vector support to (sub -1, x) -> (xor x, -1) canonicalization
Improves commutation potential

llvm-svn: 284113
2016-10-13 12:05:20 +00:00
Simon Pilgrim 08190943cb [DAGCombiner] Update most ADD combines to support general vector combines
Add a number of helper functions to match scalar or vector equivalent constant/splat values to allow most of the combine patterns to be used by vectors.

Differential Revision: https://reviews.llvm.org/D25374

llvm-svn: 284015
2016-10-12 13:48:10 +00:00
Konstantin Zhuravlyov 081385a74e [DAGCombiner] Do not remove the load of stored values when optimizations are disabled
This combiner breaks debug experience and should not be run when optimizations are disabled.

For example:
  int main() {
    int j = 0;
    j += 2;
    if (j == 2)
      return 0;
    return 5;
  }
When debugging this code compiled in /O0, it should be valid to break at line "j+=2;" and edit the value of j. It should change the return value of the function.

Differential Revision: https://reviews.llvm.org/D19268

llvm-svn: 284014
2016-10-12 13:44:24 +00:00
Michael Kuperstein 7adbf6b042 [DAG] Fix crash in build_vector -> vector_shuffle combine
Fixes a crash in the build_vector -> vector_shuffle combine
when the first vector input is twice as wide as the output,
and the second input vector is even wider.

llvm-svn: 283953
2016-10-11 22:44:31 +00:00
Sanjay Patel 8253e15ef3 [DAG] add fold for masked negated sign-extended bool
This enhances the fold added with:
https://reviews.llvm.org/rL283900

llvm-svn: 283905
2016-10-11 17:05:52 +00:00
Sanjay Patel 8384703d9b [DAG] add fold for masked negated extended bool
The non-obvious motivation for adding this fold (which already happens in InstCombine)
is that we want to canonicalize IR towards select instructions and canonicalize DAG 
nodes towards boolean math. So we need to recreate some folds in the DAG to handle that
change in direction. 

An interesting implementation difference for cases like this is that InstCombine
generally works top-down while the DAG goes bottom-up. That means we need to detect 
different patterns. In this case, the SimplifyDemandedBits fold prevents us from 
performing a zext to sext fold that would then be recognized as a negation of a sext. 

llvm-svn: 283900
2016-10-11 16:26:36 +00:00
Sanjay Patel 38a42e4bfa [DAG] simplify logic; NFC
llvm-svn: 283885
2016-10-11 14:14:30 +00:00
Sanjay Patel 907ae69125 [DAG] hoist DL(N) and fix formatting; NFC
llvm-svn: 283884
2016-10-11 14:04:24 +00:00
Sanjay Patel 9609f3d6c7 [DAG] fix formatting; NFC
llvm-svn: 283878
2016-10-11 13:47:43 +00:00
Sanjay Patel 14c02052d6 [DAG] clean up foldSelectOfConstants(); NFCI
Rename variables, simplify logic. 
Not clear yet why we don't handle a target with ZeroOrNegativeOneBooleanContent too.

llvm-svn: 283613
2016-10-07 21:55:42 +00:00
Sanjay Patel ecaf343fe7 [DAG] move fold (select C, 0, 1 -> xor C, 1) to a helper function; NFC
We're missing at least 3 other similar folds based on what we have in InstCombine. 

llvm-svn: 283596
2016-10-07 20:47:51 +00:00
Vedant Kumar 7beb423765 Delete some dead code in SelectionDAG (NFC)
Differential Revision: https://reviews.llvm.org/D24435

llvm-svn: 283505
2016-10-06 22:53:43 +00:00
Michael Kuperstein 7cc2123847 [DAG] Generalize build_vector -> vector_shuffle combine for more than 2 inputs
This generalizes the build_vector -> vector_shuffle combine to support any
number of inputs. The idea is to create a binary tree of shuffles, where
the first layer performs pairwise shuffles of the input vectors placing each
input element into the correct lane, and the rest of the tree blends these
shuffles together.

This doesn't try to be smart and create any sort of "optimal" shuffles.
The assumption is that even a "poor" shuffle sequence is better than extracting
and inserting the elements one by one.

Differential Revision: https://reviews.llvm.org/D24683

llvm-svn: 283480
2016-10-06 18:58:24 +00:00
Sanjay Patel f7df85af87 fix formatting; NFC
llvm-svn: 283115
2016-10-03 15:18:36 +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
Michael Kuperstein 3e06eafc20 [DAG] Remove isVectorClearMaskLegal() check from vector_build dagcombine
This check currently doesn't seem to do anything useful on any in-tree target:
On non-x86, it always evaluates to false, so we never hit the code path that
creates the shuffle with zero.
On x86, it just forwards to isShuffleMaskLegal(), which is a reasonable thing to
query in general, but doesn't make sense if only restricted to zero blends.

Differential Revision: https://reviews.llvm.org/D24625

llvm-svn: 282567
2016-09-28 06:13:58 +00:00
Wei Mi ab24cd189f Change the order of the splitted store from high - low to low - high.
It is a trivial change which could make the testcase easier to be reused
for the store splitting in CodeGenPrepare.

llvm-svn: 281846
2016-09-18 06:10:32 +00:00
Sanjay Patel b1f0a0f4a8 getValueType().getSizeInBits() -> getValueSizeInBits() ; NFCI
llvm-svn: 281493
2016-09-14 16:05:51 +00:00
Sanjay Patel 5f6bb6cd24 getValueType().getScalarSizeInBits() -> getScalarValueSizeInBits() ; NFCI
llvm-svn: 281490
2016-09-14 15:43:44 +00:00
Sanjay Patel bd6fca1419 getScalarType().getSizeInBits() -> getScalarSizeInBits() ; NFCI
llvm-svn: 281489
2016-09-14 15:21:00 +00:00
Michael Kuperstein 59f8305305 [DAG] Allow build-to-shuffle combine to combine builds from two wide vectors.
This allows us to, in some cases, create a vector_shuffle out of a build_vector, when
the inputs to the build are extract_elements from two different vectors, at least one
of which is wider than the output. (E.g. a <8 x i16> being constructed out of
elements from a <16 x i16> and a <8 x i16>).

Differential Revision: https://reviews.llvm.org/D24491

llvm-svn: 281402
2016-09-13 21:53:32 +00:00
Simon Pilgrim 4a8eba3e96 [DAGCombiner] Use APInt directly in (shl (zext (srl x, C)), C) combine range test
To avoid assertion, we must ensure that the inner shift constant is within range before calling ConstantSDNode::getZExtValue(). We already know that the outer shift constant is in range.

Followup to D23007

llvm-svn: 281362
2016-09-13 18:33:29 +00:00
Simon Pilgrim bd28a85d14 [DAGCombiner] Use APInt directly in (shl (ext (shl x, c1)), c2) combine
Fix failure to detect out of range shift constants leading to assert in ConstantSDNode::getZExtValue()

Followup to D23007

llvm-svn: 281354
2016-09-13 17:15:28 +00:00
Ayman Musa 0c2da88f82 Remove MVT:i1 xor instruction before SELECT. (Performance improvement).
Differential Revision: https://reviews.llvm.org/D23764

llvm-svn: 281308
2016-09-13 09:12:45 +00:00
Michael Kuperstein efc0667583 [DAG] Refactor BUILD_VECTOR combine to make it easier to extend. NFCI.
This should make it easier to add cases that we currently don't cover,
like supporting more kinds of type mismatches and more than 2 input vectors.

llvm-svn: 281283
2016-09-13 00:57:43 +00:00
Justin Lebar adbf09e8cf [CodeGen] Split out the notions of MI invariance and MI dereferenceability.
Summary:
An IR load can be invariant, dereferenceable, neither, or both.  But
currently, MI's notion of invariance is IR-invariant &&
IR-dereferenceable.

This patch splits up the notions of invariance and dereferenceability at
the MI level.  It's NFC, so adds some probably-unnecessary
"is-dereferenceable" checks, which we can remove later if desired.

Reviewers: chandlerc, tstellarAMD

Subscribers: jholewinski, arsenm, nemanjai, llvm-commits

Differential Revision: https://reviews.llvm.org/D23371

llvm-svn: 281151
2016-09-11 01:38:58 +00:00
Simon Pilgrim 153b408433 [SelectionDAG] Ensure DAG::getZeroExtendInReg is called with a scalar type
Fixes issue with rL280927 identified by Mikael Holmén

llvm-svn: 281042
2016-09-09 13:31:52 +00:00
Simon Pilgrim a01ee07a19 [DAGCombiner] Enable AND combines of splatted constant vectors
Allow AND combines to use a vector splatted constant as well as a constant scalar.

Preliminary part of D24253.

llvm-svn: 280926
2016-09-08 12:36:39 +00:00
Hal Finkel 8ca2ed22b2 [DAGCombine] More fixups to SETCC legality checking (visitANDLike/visitORLike)
I might have called this "r246507, the sequel". It fixes the same issue, as the
issue has cropped up in a few more places. The underlying problem is that
isSetCCEquivalent can pick up select_cc nodes with a result type that is not
legal for a setcc node to have, and if we use that type to create new setcc
nodes, nothing fixes that (and so we've violated the contract that the
infrastructure has with the backend regarding setcc node types).

Fixes PR30276.

For convenience, here's the commit message from r246507, which explains the
problem is greater detail:

[DAGCombine] Fixup SETCC legality checking

SETCC is one of those special node types for which operation actions (legality,
etc.) is keyed off of an operand type, not the node's value type. This makes
sense because the value type of a legal SETCC node is determined by its
operands' value type (via the TLI function getSetCCResultType). When the
SDAGBuilder creates SETCC nodes, it either creates them with an MVT::i1 value
type, or directly with the value type provided by TLI.getSetCCResultType.

The first problem being fixed here is that DAGCombine had several places
querying TLI.isOperationLegal on SETCC, but providing the return of
getSetCCResultType, instead of the operand type directly. This does not mean
what the author thought, and "luckily", most in-tree targets have SETCC with
Custom lowering, instead of marking them Legal, so these checks return false
anyway.

The second problem being fixed here is that two of the DAGCombines could create
SETCC nodes with arbitrary (integer) value types; specifically, those that
would simplify:

  (setcc a, b, op1) and|or (setcc a, b, op2) -> setcc a, b, op3
     (which is possible for some combinations of (op1, op2))

If the operands of the and|or node are actual setcc nodes, then this is not an
issue (because the and|or must share the same type), but, the relevant code in
DAGCombiner::visitANDLike and DAGCombiner::visitORLike actually calls
DAGCombiner::isSetCCEquivalent on each operand, and that function will
recognise setcc-like select_cc nodes with other return types. And, thus, when
creating new SETCC nodes, we need to be careful to respect the value-type
constraint. This is even true before type legalization, because it is quite
possible for the SELECT_CC node to have a legal type that does not happen to
match the corresponding TLI.getSetCCResultType type.

To be explicit, there is nothing that later fixes the value types of SETCC
nodes (if the type is legal, but does not happen to match
TLI.getSetCCResultType). Creating SETCCs with an MVT::i1 value type seems to
work only because, either MVT::i1 is not legal, or it is what
TLI.getSetCCResultType returns if it is legal. Fixing that is a larger change,
however. For the time being, restrict the relevant transformations to produce
only SETCC nodes with a value type matching TLI.getSetCCResultType (or MVT::i1
prior to type legalization).

Fixes PR24636.

llvm-svn: 280767
2016-09-06 23:02:23 +00:00
Wei Mi c54d1298f5 Split the store of a wide value merged from an int-fp pair into multiple stores.
For the store of a wide value merged from a pair of values, especially int-fp pair,
sometimes it is more efficent to split it into separate narrow stores, which can
remove the bitwise instructions or sink them to colder places.

Now the feature is only enabled on x86 target, and only store of int-fp pair is
splitted. It is possible that the application scope gets extended with perf evidence
support in the future.

Differential Revision: https://reviews.llvm.org/D22840

llvm-svn: 280505
2016-09-02 17:17:04 +00:00
Andrea Di Biagio fd503e5af3 [DAGcombiner] Fix incorrect sinking of a truncate into the operand of a shift.
This fixes a regression introduced by revision 268094.
Revision 268094 added the following dag combine rule:
// trunc (shl x, K) -> shl (trunc x), K => K < vt.size / 2

That rule converts a truncate of a shift-by-constant into a shift of a truncated
value. We do this only if the shift count is less than half the size in bits of
the truncated value (K < vt.size / 2).

The problem is that the constraint on the shift count is incorrect, so the rule
doesn't work well in some cases involving vector types. The combine rule should
have been written instead like this:
// trunc (shl x, K) -> shl (trunc x), K => K < vt.getScalarSizeInBits()

Basically, if K is smaller than the "scalar size in bits" of the truncated value
then we know that by "sinking" the truncate into the operand of the shift we
would never accidentally make the shift undefined.

This patch fixes the check on the shift count, and adds test cases to make sure
that we don't regress the behavior.

Differential Revision: https://reviews.llvm.org/D24154

llvm-svn: 280482
2016-09-02 11:29:09 +00:00
Michael Kuperstein 65bc3c89ff [DAGCombine] Don't fold a trunc if it feeds an anyext
Legalization tends to create anyext(trunc) patterns. This should always be
combined - into either a single trunc, a single ext, or nothing if the
types match exactly. But if we happen to combine the trunc first, we may pull
the trunc away from the anyext or make it implicit (e.g. the truncate(extract)
-> extract(bitcast) fold).

To prevent this, we can avoid doing the fold, similarly to how we already handle
fpround(fpextend).

Differential Revision: https://reviews.llvm.org/D23893

llvm-svn: 280386
2016-09-01 17:59:24 +00:00
Simon Pilgrim 02b13d4d3c Use SDValue::getOpcode() helper instead of via SDValue::getNode()
llvm-svn: 279381
2016-08-20 20:04:18 +00:00
Justin Bogner cd1d5aaf2e Replace a few more "fall through" comments with LLVM_FALLTHROUGH
Follow up to r278902. I had missed "fall through", with a space.

llvm-svn: 278970
2016-08-17 20:30:52 +00:00
David Majnemer 0d955d0bf5 Use the range variant of find instead of unpacking begin/end
If the result of the find is only used to compare against end(), just
use is_contained instead.

No functionality change is intended.

llvm-svn: 278433
2016-08-11 22:21:41 +00:00
David Majnemer 0a16c22846 Use range algorithms instead of unpacking begin/end
No functionality change is intended.

llvm-svn: 278417
2016-08-11 21:15:00 +00:00
Simon Pilgrim 85c7ea86ae [DAGCombine] Avoid INSERT_SUBVECTOR reinsertions (PR28678)
If the input vector to INSERT_SUBVECTOR is another INSERT_SUBVECTOR, and this inserted subvector replaces the last insertion, then insert into the common source vector.

i.e. 
INSERT_SUBVECTOR( INSERT_SUBVECTOR( Vec, SubOld, Idx ), SubNew, Idx ) --> INSERT_SUBVECTOR( Vec, SubNew, Idx )

Differential Revision: https://reviews.llvm.org/D23330

llvm-svn: 278211
2016-08-10 10:50:53 +00:00
Simon Pilgrim 76964e3140 [DAGCombiner] Better support for shifting large value type by constants
As detailed on D22726, much of the shift combining code assume constant values will fit into a uint64_t value and calls ConstantSDNode::getZExtValue where it probably shouldn't (leading to asserts). Using APInt directly avoids this problem but we encounter other assertions if we attempt to compare/operate on 2 APInt of different bitwidths.

This patch adds a helper function to ensure that 2 APInt values are zero extended as required so that they can be safely used together. I've only added an initial example use for this to the '(SHIFT (SHIFT x, c1), c2) --> (SHIFT x, (ADD c1, c2))' combines. Further cases can easily be added as required.

Differential Revision: https://reviews.llvm.org/D23007

llvm-svn: 278141
2016-08-09 17:39:11 +00:00
Nikolai Bozhenov f679530ba1 [X86] Heuristic to selectively build Newton-Raphson SQRT estimation
On modern Intel processors hardware SQRT in many cases is faster than RSQRT
followed by Newton-Raphson refinement. The patch introduces a simple heuristic
to choose between hardware SQRT instruction and Newton-Raphson software
estimation.

The patch treats scalars and vectors differently. The heuristic is that for
scalars the compiler should optimize for latency while for vectors it should
optimize for throughput. It is based on the assumption that throughput bound
code is likely to be vectorized.

Basically, the patch disables scalar NR for big cores and disables NR completely
for Skylake. Firstly, scalar SQRT has shorter latency than NR code in big cores.
Secondly, vector SQRT has been greatly improved in Skylake and has better
throughput compared to NR.

Differential Revision: https://reviews.llvm.org/D21379

llvm-svn: 277725
2016-08-04 12:47:28 +00:00
Diana Picus ddddbc2440 Typo fix in comment. NFC
llvm-svn: 277704
2016-08-04 08:25:08 +00:00
Michael Kuperstein c97da7f3a4 [DAGCombine] Make sext(setcc) combine respect getBooleanContents
We used to combine "sext(setcc x, y, cc) -> (select (setcc x, y, cc), -1, 0)"
Instead, we should combine to (select (setcc x, y, cc), T, 0) where the value
of T is 1 or -1, depending on the type of the setcc, and getBooleanContents()
for the type if it is not i1.

This fixes PR28504.

llvm-svn: 277371
2016-08-01 19:39:49 +00:00
Matthias Braun 941a705b7b MachineFunction: Return reference for getFrameInfo(); NFC
getFrameInfo() never returns nullptr so we should use a reference
instead of a pointer.

llvm-svn: 277017
2016-07-28 18:40:00 +00:00
Simon Pilgrim 10bf0ff879 [DAGCombiner] Use APInt directly to detect out of range shift constants
Using getZExtValue() will assert if the value doesn't fit into uint64_t - SHL was already doing this, I've just updated ASHR/LSHR to match

As mentioned on D22726

llvm-svn: 276855
2016-07-27 10:30:55 +00:00
Justin Lebar 9c375817ac [SelectionDAG] Get rid of bool parameters in SelectionDAG::getLoad, getStore, and friends.
Summary:
Instead, we take a single flags arg (a bitset).

Also add a default 0 alignment, and change the order of arguments so the
alignment comes before the flags.

This greatly simplifies many callsites, and fixes a bug in
AMDGPUISelLowering, wherein the order of the args to getLoad was
inverted.  It also greatly simplifies the process of adding another flag
to getLoad.

Reviewers: chandlerc, tstellarAMD

Subscribers: jholewinski, arsenm, jyknight, dsanders, nemanjai, llvm-commits

Differential Revision: http://reviews.llvm.org/D22249

llvm-svn: 275592
2016-07-15 18:27:10 +00:00
Sanjay Patel fedc01ad76 [DAG] make isConstantSplatVector() available to the rest of lowering
llvm-svn: 275025
2016-07-10 21:27:06 +00:00
Sanjay Patel 303326541b reformat, fix comments/names; NFCI
llvm-svn: 275015
2016-07-10 13:05:57 +00:00
Matt Arsenault 3fb8f9eabf Reapply r274829 with fix for FP vectors
llvm-svn: 274937
2016-07-08 21:25:33 +00:00
Nico Weber 28410c6846 Revert r274829, it caused PR28472.
llvm-svn: 274916
2016-07-08 19:52:19 +00:00
Sjoerd Meijer 1ee119f897 Do not expand SDIV when compiling for minimum code size
Differential Revision: http://reviews.llvm.org/D22139

llvm-svn: 274855
2016-07-08 15:32:01 +00:00
Sjoerd Meijer 46c4c3d31c Addressing post-commit comments regarding not expanding UDIV;
we don't expand only when compiling for minimum code size.

llvm-svn: 274847
2016-07-08 14:17:09 +00:00
Sjoerd Meijer a625af3feb Code size optimisation: don't expand a div to a mul and and a shift sequence.
As a result, the urem instruction will not be expanded to a sequence of umull,
lsrs, muls and sub instructions, but just a call to __aeabi_uidivmod.

Differential Revision: http://reviews.llvm.org/D22131

llvm-svn: 274843
2016-07-08 12:54:43 +00:00
Matt Arsenault c3a6fe6ecd Bug 28444: Fix assertion when extract_vector_elt has mismatched type
For some reason extract_vector_elt is sometimes allowed to have
a different result type than the vector element type.

llvm-svn: 274829
2016-07-08 07:05:00 +00:00
Tim Shen 1c3c0afc53 [DAGCombiner] Fix visitSTORE to continue processing current SDNode, if findBetterNeighborChains doesn't actually CombineTo it.
Summary:
findBetterNeighborChains may or may not find a better chain for each node it finds, which include the node ("St") that visitSTORE is currently processing. If no better chain is found for St, visitSTORE should continue instead of return SDValue(St, 0), as if it's CombinedTo'ed.

This fixes bug 28130. There might be other ways to make the test pass (see D21409). I think both of the patches are fixing actual bugs revealed by the same testcase.

Reviewers: echristo, wschmidt, hfinkel, kbarton, amehsan, arsenm, nemanjai, bogner

Subscribers: mehdi_amini, nemanjai, llvm-commits

Differential Revision: http://reviews.llvm.org/D21692

llvm-svn: 274644
2016-07-06 17:44:03 +00:00
Balaram Makam d4acd7ed10 Revert r259387: "AArch64: Implement missed conditional compare sequences."
This reverts commit r259387 because it inserts illegal code after legalization
    in some backends where i64 OR type is illegal for example.

llvm-svn: 274573
2016-07-05 20:24:05 +00:00
Matt Arsenault 2d79389508 DAGCombiner: Fold away vector extract of insert with the same index
This only really matters when the index is non-constant since the
constant case already gets taken care of by other combines.

llvm-svn: 274569
2016-07-05 18:25:02 +00:00
Craig Topper d1eca0f32c [CodeGen] Teach OR combine of shuffles involving zero vectors to better handle undef indices.
Undef indices can now be treated as zeros. Or if its undef ORed with zero, we will keep the undef.

llvm-svn: 274472
2016-07-03 19:37:12 +00:00
Craig Topper 2bd8b4b180 [CodeGen,Target] Remove the version of DAG.getVectorShuffle that takes a pointer to a mask array. Convert all callers to use the ArrayRef version. No functional change intended.
For the most part this simplifies all callers. There were two places in X86 that needed an explicit makeArrayRef to shorten a statically sized array.

llvm-svn: 274337
2016-07-01 06:54:47 +00:00