Create PMULDQ/PMULUDQ as long as the number of elements is a power of 2.
This seems to give some improvements in our ability to use SimplifyDemandedBits.
llvm-svn: 350084
This is an alternative to what I attempted in D56057.
GetDemandedBits is a special version of SimplifyDemandedBits that allows simplifications even when the operand has other uses. GetDemandedBits will only do simplifications that allow a node to be bypassed. It won't create new nodes or alter any of the other users.
I had to add support for bypassing SIGN_EXTEND_INREG to GetDemandedBits.
Based on a patch that Simon Pilgrim sent me in email.
Fixes PR40142.
llvm-svn: 350059
It's dangerous to knowingly create an illegal vector type
no matter what stage of combining we're in.
This prevents the missed folding/scalarization seen in:
https://bugs.llvm.org/show_bug.cgi?id=40146
llvm-svn: 350034
trunc (add X, C ) --> add (trunc X), C'
If we're throwing away the top bits of an 'add' instruction, do it in the narrow destination type.
This makes the truncate-able opcode list identical to the sibling transform done in IR (in instcombine).
This change used to show regressions for x86, but those are gone after D55494.
This gets us closer to deleting the x86 custom function (combineTruncatedArithmetic)
that does almost the same thing.
Differential Revision: https://reviews.llvm.org/D55866
llvm-svn: 350006
The missed load folding noticed in D55898 is visible independent of that change
either with an adjusted IR pattern to start or with AVX2/AVX512 (where the build
vector becomes a broadcast first; movddup is not produced until we get into isel
via tablegen patterns).
Differential Revision: https://reviews.llvm.org/D55936
llvm-svn: 350005
@bextr64_32_b1 is extracted from hotpath of real-world code
(RawSpeed BitStream<>::peekBitsNoFill()) after `clang -O3`.
@bextr64_32_b2/@bextr64_32_b0 is the same pattern,
but with trunc done last, showing how i think it can be handled:
https://rise4fun.com/Alive/K4Bhttps://rise4fun.com/Alive/qC9
It is possible that middle-end should do some of this, too.
https://bugs.llvm.org/show_bug.cgi?id=36419
llvm-svn: 349998
This fixes the patterns that have or/and as a root. 'and' is handled differently since thy usually have a CMP wrapped around them.
I had to look for uses of the CF flag because all these nodes have non-standard CF flag behavior. A real or/xor would always clear CF. In practice we shouldn't be using the CF flag from these nodes as far as I know.
Differential Revision: https://reviews.llvm.org/D55813
llvm-svn: 349962
The BEXTR instruction documents the SF bit as undefined.
The TBM BEXTR instruction has the same issue, but I'm not sure how to test it. With the control being an immediate we can determine the sign bit is 0 or the BEXTR would have been removed.
Fixes PR40060
Differential Revision: https://reviews.llvm.org/D55807
llvm-svn: 349956
This is admittedly a narrow fix for the problem:
https://bugs.llvm.org/show_bug.cgi?id=37502
...but as the XOP restriction shows, it's a maze to get this right.
In the motivating example, note that we have movddup before SSE4.1 and
again with AVX2. That's because insertps isn't available pre-SSE41 and
vbroadcast is (more generally) available with AVX2 (and the splat is
reduced to movddup via isel pattern).
Differential Revision: https://reviews.llvm.org/D55898
llvm-svn: 349937
This adds an AVX512 run as suggested in D55936.
The test didn't really belong with other build vector tests
because that's not the pattern here. I don't see much value
in adding 64-bit RUNs because they wouldn't exercise the
isel patterns that we're aiming to expose.
llvm-svn: 349920
This patch enables funnel shift -> rotate building for all ROTL/ROTR custom/legal operations.
AFAICT X86 was the last target that was missing modulo support (PR38243), but I've tried to CC stakeholders for every target that has ROTL/ROTR custom handling for their final OK.
Differential Revision: https://reviews.llvm.org/D55747
llvm-svn: 349765
Summary:
This allows expanding {7,11,13,14,15,21,22,23,25,26,27,28,29,30,31}-byte memcmp
in just two loads on X86. These were previously calling memcmp.
Reviewers: spatel, gchatelet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D55263
llvm-svn: 349731
The (cmp (and X, Y) 0) pattern is greedy and ends up forming a TESTrr and consuming the and when it might be better to use one of the BMI/TBM like BLSR or BLSI.
This patch moves removes the pattern from isel and adds a post processing check to combine TESTrr+ANDrr into just a TESTrr. With this patch we are able to select the BMI/TBM instructions, but we'll also emit a TESTrr when the result is compared to 0. In many cases the peephole pass will be able to use optimizeCompareInstr to remove the TEST, but its probably not perfect.
Differential Revision: https://reviews.llvm.org/D55870
llvm-svn: 349661
Fixes https://bugs.llvm.org/show_bug.cgi?id=38743
The function removeRedundantBlockingStores is supposed to remove any blocking stores contained in each other in lockingStoresDispSizeMap.
But it currently looks only at the previous one, which will miss some cases that result in assert.
This patch refine the function to check all previous layouts until find the uncontained one. So all redundant stores will be removed.
Patch by Pengfei Wang
Differential Revision: https://reviews.llvm.org/D55642
llvm-svn: 349660
Now that we use the generic ISD opcodes, we can use the generic intrinsics directly as well. This fixes the poor fast-isel codegen by not expanding to an easily broken IR code sequence.
I'm intending to deal with the signed saturation equivalents as well.
Clang counterpart: https://reviews.llvm.org/D55879
Differential Revision: https://reviews.llvm.org/D55855
llvm-svn: 349630
Now that SimplifyDemandedBits/SimplifyDemandedVectorElts is simplifying vector elements, we're seeing more constant BUILD_VECTOR containing undefs.
This patch provides opt-in support for UNDEF elements in matchBinaryPredicate, passing NULL instead of the result ConstantSDNode* argument.
I've updated the (or (and X, c1), c2) -> (and (or X, c2), c1|c2) fold to demonstrate its use, which I believe is safe for undef cases.
Differential Revision: https://reviews.llvm.org/D55822
llvm-svn: 349629
As described on PR40091, we have several places where zext (and zext_vector_inreg) fold an undef input into an undef output. For zero extensions this is incorrect as the output should guarantee to least have the new upper bits set to zero.
SimplifyDemandedVectorElts is the worst offender (and its the most likely to cause new undefs to appear) but DAGCombiner's tryToFoldExtendOfConstant has a similar issue.
Thanks to @dmgreen for catching this.
Differential Revision: https://reviews.llvm.org/D55883
llvm-svn: 349625
These are due to be upgraded soon, but good to replace them with generic llvm sadd_sat/ssub_sat intrinsics now.
The avx512 masked cases need doing as well but require a bit of tidyup first.
llvm-svn: 349621
Now that SimplifyDemandedBits/SimplifyDemandedVectorElts are simplifying vector elements, we're seeing more constant BUILD_VECTOR containing UNDEFs.
This patch provides opt-in handling of UNDEF elements in matchUnaryPredicate, passing NULL instead of the ConstantSDNode* argument.
I've updated SelectionDAG::simplifyShift to demonstrate its use.
Differential Revision: https://reviews.llvm.org/D55819
llvm-svn: 349616
These are already being autoupgraded, currently to an IR sequence, but best to replace them with generic llvm uadd_sat/usub_sat intrinsics (which D55855 will be doing shortly anyhow).
The avx512 masked cases need doing as well but require a bit of tidyup first.
llvm-svn: 349615
SelectionDAG currently changes these intrinsics to function calls, but that won't work
for other ISel's. Also we want to eventually support nonlazybind and weak linkage coming
from the front-end which we can't do in SelectionDAG.
llvm-svn: 349552
We already had BSF here as part of __builtin_ffs improvements and I was just wondering yesterday whether we should have BSR there.
This addresses one issue from PR40090.
llvm-svn: 349531
Migrate the X86 backend from X86ISD opcodes ADDS and SUBS to generic
ISD opcodes SADDSAT and SSUBSAT. This also improves scodegen for
@llvm.sadd.sat() and @llvm.ssub.sat() intrinsics.
This is a followup to D55787 and part of PR40056.
Differential Revision: https://reviews.llvm.org/D55833
llvm-svn: 349520
InstCombine seems to canonicalize or PSUB patter into a max with the cosntant and an add with an inverse of the constant.
This patch recognizes this pattern and turns it into PSUBUS. Future work could improve undef element handling.
Fixes some of PR40053
Differential Revision: https://reviews.llvm.org/D55780
llvm-svn: 349519
Replace the X86ISD opcodes ADDUS and SUBUS with generic ISD opcodes
UADDSAT and USUBSAT. As a side-effect, this also makes codegen for
the @llvm.uadd.sat and @llvm.usub.sat intrinsics reasonable.
This only replaces use in the X86 backend, and does not move any of
the ADDUS/SUBUS X86 specific combines into generic codegen.
Differential Revision: https://reviews.llvm.org/D55787
llvm-svn: 349481
For opcodes not covered by SimplifyDemandedVectorElts, SimplifyDemandedBits might be able to help now that it supports demanded elts as well.
llvm-svn: 349466
This fold was incredibly specific - replace with a SimplifyDemandedBits fold to remove a VSRAI if only the original sign bit is demanded (its guaranteed to stay the same).
Test change is merely a rescheduling.
llvm-svn: 349459
Convert VSRAI to VSRLI is the sign bit is known zero and improve KnownBits output for all shift instruction.
Fixes the poor codegen comments in D55768.
llvm-svn: 349407
This allows a TEST to be used and can be combined with any AND that may already exist as an input to the shift.
This was already done in EmitTest, but was easily tricked by multiple uses because the setcc might be used by multiple instructions. Once the SETCC and users are legalized then we can look for the shift to be used by a single CMP, but the CMP itself can have multiple users.
This appears to fix the case in PR39968.
llvm-svn: 349385
This is an initial patch to add the necessary support for a DemandedElts argument to SimplifyDemandedBits, more closely matching computeKnownBits and to help improve vector codegen.
I've added only a small amount of the changes necessary to get at least one test to update - a lot more can be done but I'd like to add these methodically with proper test coverage, at the same time the hope is to slowly move some/all of SimplifyDemandedVectorElts into SimplifyDemandedBits as well.
Differential Revision: https://reviews.llvm.org/D55768
llvm-svn: 349374
I'd like to try to move a lot of the flag matching out of EmitTest and push it to isel or isel preprocessing. This is a step towards that.
The test-shrink-bug.ll changie is an improvement because we are no longer interfering with test shrink handling in isel.
The pr34137.ll change is a regression, but the IR came from -O0 and was not reduced by InstCombine. So it contains a lot of redundancies like duplicate loads that made it combine poorly.
llvm-svn: 349315
The transform performs a bitwise logic op in a wider type followed by
truncate when both inputs are truncated from the same source type:
logic_op (truncate x), (truncate y) --> truncate (logic_op x, y)
There are a bunch of other checks that should prevent doing this when
it might be harmful.
We already do this transform for scalars in this spot. The vector
limitation was shared with a check for the case when the operands are
extended. I'm not sure if that limit is needed either, but that would
be a separate patch.
Differential Revision: https://reviews.llvm.org/D55448
llvm-svn: 349303
Also exposes an issue in DAGCombiner::visitFunnelShift where we were assuming the shift amount had the result type (after legalization it'll have the targets shift amount type).
llvm-svn: 349298
Use consistent rules for when to lower to SHLD/SHRD for slow machines - fixes a weird issue where funnel shift gets expanded but then X86ISelLowering's combineOr sees the optsize and combines to SHLD/SHRD, but now with the modulo amount guard......
llvm-svn: 349285
Summary:
Make machine PHIs optimization to work for single value register taken from
several different copies. This is the first step to fix PR38917. This change
allows to get rid of redundant PHIs (see opt_phis2.mir test) to make
the subsequent optimizations (like CSE) possible and simpler.
For instance, before this patch the code like this:
%b = COPY %z
...
%a = PHI %bb1, %a; %bb2, %b
could be optimized to:
%a = %b
but the code like this:
%c = COPY %z
...
%b = COPY %z
...
%a = PHI %bb1, %a; %bb2, %b; %bb3, %c
would remain unchanged.
With this patch the latter case will be optimized:
%a = %z```.
Committed on behalf of: Anton Afanasyev anton.a.afanasyev@gmail.com
Reviewers: RKSimon, MatzeB
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D54839
llvm-svn: 349271
Implement options in clang to enable recording the driver command-line
in an ELF section.
Implement a new special named metadata, llvm.commandline, to support
frontends embedding their command-line options in IR/ASM/ELF.
This differs from the GCC implementation in some key ways:
* In GCC there is only one command-line possible per compilation-unit,
in LLVM it mirrors llvm.ident and multiple are allowed.
* In GCC individual options are separated by NULL bytes, in LLVM entire
command-lines are separated by NULL bytes. The advantage of the GCC
approach is to clearly delineate options in the face of embedded
spaces. The advantage of the LLVM approach is to support merging
multiple command-lines unambiguously, while handling embedded spaces
with escaping.
Differential Revision: https://reviews.llvm.org/D54487
Clang Differential Revision: https://reviews.llvm.org/D54489
llvm-svn: 349155
It costs nothing to spill an IMPLICIT_DEF value (the only spill code that's
generated is a KILL of the value), so when creating split constraints if the
live-out value is IMPLICIT_DEF the exit constraint should be DontCare instead
of PrefReg.
Differential Revision: https://reviews.llvm.org/D55652
llvm-svn: 349151
This is a retry of rL349051 (reverted at rL349056). I changed the check for dead-ness from
number of uses to an opcode test for DELETED_NODE based on existing similar code.
Differential Revision: https://reviews.llvm.org/D55655
llvm-svn: 349058
There's still a couple of minor SimplifyDemandedElts regressions in some of the shift amount splats that will be fixed in future patches.
llvm-svn: 349052
Summary:
All targets either just return false here or properly model `Fast`, so I
don't think there is any reason to prevent CodeGen from doing the right
thing here.
Subscribers: nemanjai, javed.absar, eraman, jsji, llvm-commits
Differential Revision: https://reviews.llvm.org/D55365
llvm-svn: 349016
MULX has somewhat improved register allocation constraints compared to the legacy MUL instruction. Both output registers are encoded instead of fixed to EAX/EDX, but EDX is used as input. It also doesn't touch flags. Unfortunately, the encoding is longer.
Prefering it whenever BMI2 is enabled is probably not optimal. Choosing it should somehow be a function of register allocation constraints like converting adds to three address. gcc and icc definitely don't pick MULX by default. Not sure what if any rules they have for using it.
Differential Revision: https://reviews.llvm.org/D55565
llvm-svn: 348975
A future patch may stop using MULX by default so use MIR to ensure we're always testing MULX.
Add the 32-bit case that we couldn't do in the 64-bit mode IR test due to it being promoted to a 64-bit mul.
llvm-svn: 348972
I'm hoping we can just replace SETCC_CARRY with SBB. This is another step towards that.
I've explicitly used zero as the input to the setcc to avoid a false dependency that we've had with the SETCC_CARRY. I changed one of the patterns that used NEG to instead use an explicit compare with 0 on the LHS. We needed the zero anyway to avoid the false dependency. The negate would clobber its input register. By using a CMP we can avoid that which could be useful.
Differential Revision: https://reviews.llvm.org/D55414
llvm-svn: 348959
This extends the code that handles 16-bit add promotion to form LEA to also allow 8-bit adds.
That allows us to combine add ops with register moves and save some instructions. This is
another step towards allowing add truncation in generic DAGCombiner (see D54640).
Differential Revision: https://reviews.llvm.org/D55494
llvm-svn: 348946
If either of the operand elements are zero then we know the result element is going to be zero (even if the other element is undef).
Differential Revision: https://reviews.llvm.org/D55558
llvm-svn: 348926
Add an intrinsic that takes 2 signed integers with the scale of them provided
as the third argument and performs fixed point multiplication on them.
This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.
Differential Revision: https://reviews.llvm.org/D54719
llvm-svn: 348912
Summary:
When doing X86CondBrFolding::analyzeCompare, it will meet the SUB32ri instruction as below to use the global address for its operand,
%733:gr32 = SUB32ri %62:gr32(tied-def 0), @img2buf_normal, implicit-def $eflags
JNE_1 %bb.41, implicit $eflags
so the assertion "assert(MI.getOperand(ValueIndex).isImm() && "Expecting Imm operand")" is not correct and change the assert to if make X86CondBrFolding::analyzeCompare return false as not finding the compare for this
Patch by Jianping Chen
Reviewers: smaslov, LuoYuanke, liutianle, Jianping
Reviewed By: Jianping
Subscribers: lebedev.ri, llvm-commits
Differential Revision: https://reviews.llvm.org/D54250
llvm-svn: 348853
Summary:
All targets either just return false here or properly model `Fast`, so I
don't think there is any reason to prevent CodeGen from doing the right
thing here.
Subscribers: nemanjai, javed.absar, eraman, jsji, llvm-commits
Differential Revision: https://reviews.llvm.org/D55365
llvm-svn: 348843
This patch restricts the capability of G_MERGE_VALUES, and uses the new
G_BUILD_VECTOR and G_CONCAT_VECTORS opcodes instead in the appropriate places.
This patch also includes AArch64 support for selecting G_BUILD_VECTOR of <4 x s32>
and <2 x s64> vectors.
Differential Revisions: https://reviews.llvm.org/D53629
llvm-svn: 348788
If all the demanded elements of the SimplifyDemandedVectorElts are known to be UNDEF, we can simplify to an ISD::UNDEF node.
Zero constant folding will be handled in a future patch - its a little trickier as we often have bitcasted zero values.
Differential Revision: https://reviews.llvm.org/D55511
llvm-svn: 348784
This triggers an assert when combining concat_vectors of a bitcast of
merge_values.
With asserts disabled, it fails to select:
fatal error: error in backend: Cannot select: 0x7ff19d000e90: i32 = any_extend 0x7ff19d000ae8
0x7ff19d000ae8: f64,ch = CopyFromReg 0x7ff19d000c20:1, Register:f64 %1
0x7ff19d000b50: f64 = Register %1
In function: d
Differential Revision: https://reviews.llvm.org/D55507
llvm-svn: 348759
This is a fix for PR39896, where dbg.value's of SDNodes that have been
optimised out do not lead to "DBG_VALUE undef" instructions being created.
Such undef instructions are necessary to terminate earlier variable
ranges, otherwise variable values leak past the point where they're valid.
The "invalidated" flag of SDDbgValue is currently being abused to mean two
things:
* The corresponding SDNode is now invalid
* This SDDbgValue should not be emitted
Of which there are several legitimate combinations of meaning:
* The SDNode has been invalidated and we should emit "DBG_VALUE undef"
* The SDNode has been invalidated but the debug data was salvaged, don't
emit anything for this SDDbgValue
* This SDDbgValue has been emitted
This patch introduces distinct "Emitted" and "Invalidated" fields to the
SDDbgValue class, updates users accordingly, and generates "undef"
DBG_VALUEs for invalidated records. Awkwardly, there are circumstances
where we emit SDDbgValue's twice, specifically DebugInfo/X86/dbg-addr-dse.ll
which I've preserved.
Differential Revision: https://reviews.llvm.org/D55372
llvm-svn: 348751
Fixes https://bugs.llvm.org/show_bug.cgi?id=39926.
The size of the first copy was computed as
std::abs(std::abs(LdDisp2) - std::abs(LdDisp1)), which results in
skipped bytes if the signs of LdDisp2 and LdDisp1 differ. As far as
I can see, this should just be LdDisp2 - LdDisp1. The case where
LdDisp1 > LdDisp2 is already handled in the code above, in which case
LdDisp2 is set to LdDisp1 and this subtraction will evaluate to
Size1 = 0, which is the correct value to skip an overlapping copy.
Differential Revision: https://reviews.llvm.org/D55485
llvm-svn: 348750
Both intrinsics do the exact same thing so we really only need one.
Earlier in the 8.0 cycle we changed the signature of this intrinsic without renaming it. But it looks difficult to get the autoupgrade code to allow me to merge the intrinsics and change the signature at the same time. So I've renamed the intrinsic slightly for the new merged intrinsic. I'm skipping autoupgrading from the previous new to 8.0 signature. I've also renamed the subborrow for consistency.
llvm-svn: 348737
Previously we had to take the carry in and add -1 to it to set the carry flag so we could use it with ADC/SBB. But if we know its 0 then we don't need to bother.
This should go a long way towards fixing PR24545.
llvm-svn: 348727
The existing code tries to handle an undef operand while transforming an add to an LEA,
but it's incomplete because we will crash on the i16 test with the debug output shown below.
It's better to just give up instead. Really, GlobalIsel should have folded these before we
could get into trouble.
# Machine code for function add_undef_i16: NoPHIs, TracksLiveness, Legalized, RegBankSelected, Selected
bb.0 (%ir-block.0):
liveins: $edi
%1:gr32 = COPY killed $edi
%0:gr16 = COPY %1.sub_16bit:gr32
%5:gr64_nosp = IMPLICIT_DEF
%5.sub_16bit:gr64_nosp = COPY %0:gr16
%6:gr64_nosp = IMPLICIT_DEF
%6.sub_16bit:gr64_nosp = COPY %2:gr16
%4:gr32 = LEA64_32r killed %5:gr64_nosp, 1, killed %6:gr64_nosp, 0, $noreg
%3:gr16 = COPY killed %4.sub_16bit:gr32
$ax = COPY killed %3:gr16
RET 0, implicit killed $ax
# End machine code for function add_undef_i16.
*** Bad machine code: Reading virtual register without a def ***
- function: add_undef_i16
- basic block: %bb.0 (0x7fe6cd83d940)
- instruction: %6.sub_16bit:gr64_nosp = COPY %2:gr16
- operand 1: %2:gr16
LLVM ERROR: Found 1 machine code errors.
Differential Revision: https://reviews.llvm.org/D54710
llvm-svn: 348722
The test file shows a case where the avoid store forwarding block
pass misses to copy a range (-1..1) when the load displacement
changes sign.
Baseline test for D55485.
llvm-svn: 348712
This is effectively re-committing the changes from:
rL347917 (D54640)
rL348195 (D55126)
...which were effectively reverted here:
rL348604
...because the code had a bug that could induce infinite looping
or eventual out-of-memory compilation.
The bug was that this code did not guard against transforming
opaque constants. More details are in the post-commit mailing
list thread for r347917. A reduced test for that is included
in the x86 bool-math.ll file. (I wasn't able to reduce a PPC
backend test for this, but it was almost the same pattern.)
Original commit message for r347917:
The motivating case for this is shown in:
https://bugs.llvm.org/show_bug.cgi?id=32023
and the corresponding rot16.ll regression tests.
Because x86 scalar shift amounts are i8 values, we can end up with trunc-binop-trunc
sequences that don't get folded in IR.
As the TODO comments suggest, there will be regressions if we extend this (for x86,
we mostly seem to be missing LEA opportunities, but there are likely vector folds
missing too). I think those should be considered existing bugs because this is the
same transform that we do as an IR canonicalization in instcombine. We just need
more tests to make those visible independent of this patch.
llvm-svn: 348706
It seems to be unexpectedly passing on some bots probably because it requires asserts to fail, but doesn't say that. But we already have a patch in review to make it not xfail so I'd rather just focus on getting it passing rather than trying to figure out an unexpected pass.
llvm-svn: 348661
To make X86CondBrFoldingPass can be run with --run-pass option, this can test one wrong assertion on analyzeCompare function for SUB32ri when its operand is not imm
Patch by Jianping Chen
Differential Revision: https://reviews.llvm.org/D55412
llvm-svn: 348620
As discussed in the post-commit thread of r347917, this
transform is fighting with an existing transform causing
an infinite loop or out-of-memory, so this is effectively
reverting r347917 and its follow-up r348195 while we
investigate the bug.
llvm-svn: 348604
Adds fatal errors for any target that does not support the Tiny or Kernel
codemodels by rejigging the getEffectiveCodeModel calls.
Differential Revision: https://reviews.llvm.org/D50141
llvm-svn: 348585
If this is not a valid way to assign an SDLoc, then we get this
wrong all over SDAG.
I don't know enough about the SDAG to explain this. IIUC, theoretically,
debug info is not supposed to affect codegen. But here it has clearly
affected 3 different targets, and the x86 change is an actual improvement.
llvm-svn: 348552
This was probably organized as it was because bswap is a unary op.
But that's where the similarity to the other opcodes ends. We should
not limit this transform to scalars, and we should not try it if
either input has other uses. This is another step towards trying to
clean this whole function up to prevent it from causing infinite loops
and memory explosions.
Earlier commits in this series:
rL348501
rL348508
rL348518
llvm-svn: 348534
This patch introduces a new DAGCombiner rule to simplify concat_vectors nodes:
concat_vectors( bitcast (scalar_to_vector %A), UNDEF)
--> bitcast (scalar_to_vector %A)
This patch only partially addresses PR39257. In particular, it is enough to fix
one of the two problematic cases mentioned in PR39257. However, it is not enough
to fix the original test case posted by Craig; that particular case would
probably require a more complicated approach (and knowledge about used bits).
Before this patch, we used to generate the following code for function PR39257
(-mtriple=x86_64 , -mattr=+avx):
vmovsd (%rdi), %xmm0 # xmm0 = mem[0],zero
vxorps %xmm1, %xmm1, %xmm1
vblendps $3, %xmm0, %xmm1, %xmm0 # xmm0 = xmm0[0,1],xmm1[2,3]
vmovaps %ymm0, (%rsi)
vzeroupper
retq
Now we generate this:
vmovsd (%rdi), %xmm0 # xmm0 = mem[0],zero
vmovaps %ymm0, (%rsi)
vzeroupper
retq
As a side note: that VZEROUPPER is completely redundant...
I guess the vzeroupper insertion pass doesn't realize that the definition of
%xmm0 from vmovsd is already zeroing the upper half of %ymm0. Note that on
%-mcpu=btver2, we don't get that vzeroupper because pass vzeroupper insertion
%pass is disabled.
Differential Revision: https://reviews.llvm.org/D55274
llvm-svn: 348522
The PPC test with 2 extra uses seems clearly better by avoiding this transform.
With 1 extra use, we also prevent an extra register move (although that might
be an RA problem). The general rule should be to only make a change here if
it is always profitable. The x86 diffs are all neutral.
llvm-svn: 348518
The AVX512 diffs are neutral, but the bswap test shows a clear overreach in
hoistLogicOpWithSameOpcodeHands(). If we don't check for other uses, we can
increase the instruction count.
This could also fight with transforms trying to go in the opposite direction
and possibly blow up/infinite loop. This might be enough to solve the bug
noted here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20181203/608593.html
I did not add the hasOneUse() checks to all opcodes because I see a perf
regression for at least one opcode. We may decide that's irrelevant in the
face of potential compiler crashing, but I'll see if I can salvage that first.
llvm-svn: 348508
Because we're potentially peeking through a bitcast in this transform,
we need to use overall bitwidths rather than number of elements to
determine when it's safe to proceed.
Should fix:
https://bugs.llvm.org/show_bug.cgi?id=39893
llvm-svn: 348383
Whenever we effectively take the address of a basic block we need to
manually update that basic block to reflect that fact or later passes
such as tail duplication and tail merging can break the invariants of
the code. =/ Sadly, there doesn't appear to be any good way of
automating this or even writing a reasonable assert to catch it early.
The change seems trivially and obviously correct, but sadly the only
really good test case I have is 1000s of basic blocks. I've tried
directly writing a test case that happens to make tail duplication do
something that crashes later on, but this appears to require an
*amazingly* complex set of conditions that I've not yet reproduced.
The change is technically covered by the tests because we mark the
blocks as having their address taken, but that doesn't really count as
properly testing the functionality.
llvm-svn: 348374
fidelity checking of RIP-based references to basic blocks and other
labels.
These labels are super important for SLH tests so we should keep them
readable in the test cases.
llvm-svn: 348373
This is an initial patch to add a minimum level of support for funnel shifts to the SelectionDAG and to begin wiring it up to the X86 SHLD/SHRD instructions.
Some partial legalization code has been added to handle the case for 'SlowSHLD' where we want to expand instead and I've added a few DAG combines so we don't get regressions from the existing DAG builder expansion code.
Differential Revision: https://reviews.llvm.org/D54698
llvm-svn: 348353
It looks like MCRegAliasIterator can visit the same physical register twice. When this happens in this code in LICM we end up setting the PhysRegDef and then later in the same loop visit the register again. Now we see that PhysRegDef is set from the earlier iteration so now set PhysRegClobber.
This patch splits the loop so we have one that uses the previous value of PhysRegDef to update PhysRegClobber and second loop that updates PhysRegDef.
The X86 atomic test is an improvement. I had to add sideeffect to the two shrink wrapping tests to prevent hoisting from occurring. I'm not sure about the AMDGPU tests. It looks like the branch instruction changed at end the of the loops. And in the branch-relaxation test I think there is now "and vcc, exec, -1" instruction that wasn't there before.
Differential Revision: https://reviews.llvm.org/D55102
llvm-svn: 348330
Craig Topper