This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.
This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.
This doesn't actually modify StringRef yet, I'll do that in a follow-up.
Summary:
This is a follow up on D61634. It adds an LLVM IR intrinsic to allow better implementation of memcpy from C++.
A follow up CL will add the intrinsics in Clang.
Reviewers: courbet, theraven, t.p.northover, jdoerfert, tejohnson
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71710
This allows SimplifyDemandedBits to call SimplifyMultipleUseDemandedBits to create a simpler ISD::EXTRACT_SUBVECTOR, which is particularly useful for cases where we're splitting into subvectors anyhow.
Differential Revision: This allows SimplifyDemandedBits to call SimplifyMultipleUseDemandedBits to create a simpler ISD::EXTRACT_SUBVECTOR, which is particularly useful for cases where we're splitting into subvectors anyhow.
and macro FUNCTION likewise. NFCI.
Some functions like fmuladd don't really have a node, we should divide
the declaration form those have node to avoid introducing fake nodes.
Differential Revision: https://reviews.llvm.org/D72871
Updated FoldConstantArithmetic method signature to match that of
FoldConstantVectorArithmetic in preparation for merging the two
functions together
https://bugs.llvm.org/show_bug.cgi?id=36544
This is the first step in combining the various
FoldConstantVectorArithmetic and FoldConstantVectorArithmetic
functions into one FoldConstantArithmetic function.
Differential Revision: https://reviews.llvm.org/D72870
Unlike the existing code that I modified here, I only handle the
case where the strict_fsetcc has a single use. Not sure exactly
how to handle multiples uses.
Testing this on X86 is hard because we already have a other
combines that get rid of lowered version of the integer setcc that
this xor will eventually become. So this combine really just
saves a bunch of extra nodes being created. Not sure about other
targets.
Differential Revision: https://reviews.llvm.org/D71816
Summary:
This is a follow up on https://reviews.llvm.org/D71473#inline-647262.
There's a caveat here that `Align(1)` relies on the compiler understanding of `Log2_64` implementation to produce good code. One could use `Align()` as a replacement but I believe it is less clear that the alignment is one in that case.
Reviewers: xbolva00, courbet, bollu
Subscribers: arsenm, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, jrtc27, atanasyan, jsji, Jim, kerbowa, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D73099
Match the approach in SimplifyDemandedBits where we calculate the demanded elts and then have a common path for the ComputeKnownBits/ComputeNumSignBits call.
Match the approach in SimplifyDemandedBits/ComputeNumSignBits where we calculate the demanded elts and then have a common path for the ComputeKnownBits call.
Match the approach in SimplifyDemandedBits where we calculate the demanded elts and then have a common path for the ComputeKnownBits/ComputeNumSignBits call, additionally we only ever need original demanded elts of the base vector even if the index is unknown.
This patch also fixes up a number of cases in DAGCombine and
SelectionDAGBuilder where the size of a scalable vector is used in a
fixed-width context (thus triggering an assertion failure).
Reviewers: efriedma, c-rhodes, rovka, cameron.mcinally
Reviewed By: efriedma
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71215
In LLVM IR, vscale can be represented with an intrinsic. For some targets,
this is equivalent to the constexpr:
getelementptr <vscale x 1 x i8>, <vscale x 1 x i8>* null, i32 1
This can be used to propagate the value in CodeGenPrepare.
In ISel we add a node that can be legalized to one or more
instructions to materialize the runtime vector length.
This patch also adds SVE CodeGen support for VSCALE, which maps this
node to RDVL instructions (for scaled multiples of 16bytes) or CNT[HSD]
instructions (scaled multiples of 2, 4, or 8 bytes, respectively).
Reviewers: rengolin, cameron.mcinally, hfinkel, sebpop, SjoerdMeijer, efriedma, lattner
Reviewed by: efriedma
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68203
Summary:
WebAssembly is unique among upstream targets in that it does not at
any point use physical registers to store values. Instead, it uses
virtual registers to model positions in its value stack. This means
that some target-independent lowering activities that would use
physical registers need to use virtual registers instead for
WebAssembly and similar downstream targets. This CL generalizes the
existing `usesPhysRegsForPEI` lowering hook to
`usesPhysRegsForValues` in preparation for using it in more places.
One such place is in InstrEmitter for instructions that have variadic
defs. On register machines, it only makes sense for these defs to be
physical registers, but for WebAssembly they must be virtual registers
like any other values. This CL changes InstrEmitter to check the new
target lowering hook to determine whether variadic defs should be
physical or virtual registers.
These changes are necessary to support a generalized CALL instruction
for WebAssembly that is capable of returning an arbitrary number of
arguments. Fully implementing that instruction will require additional
changes that are described in comments here but left for a follow up
commit.
Reviewers: aheejin, dschuff, qcolombet
Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71484
This was unconditionally folding this to the source operand, even if the access was out of bounds. Use undef instead of the extract is not the first element.
This helps with some cases where 3-vectors are legalized and avoids processing the 4th component.
Original Patch by: arsenm (Matt Arsenault)
Differential Revision: https://reviews.llvm.org/D51589
Add DemandedElts handling to ISD::ANY_EXTEND and add missing ISD::ANY_EXTEND_VECTOR_INREG handling. Despite the lack of test changes this code IS being used - its just that the ANY_EXTEND ops are legalized later on (typically to ZERO_EXTEND equivalents) so we typically manage to combine later on.
The algorithm here only works if the sint_to_fp doesn't do any
rounding. Otherwise it can round before the offset fixup is
applied. Add an assert to protect this.
To avoid breaking the one test in tree that tested this code
with a set of types that fail the assert, I've enabled i32->f32
to use the i64->f32 algorithm. This only occurs when f64 isn't
a legal type. If f64 is legal then we do i32->f64->f32 instead.
Differential Revision: https://reviews.llvm.org/D72794
This was dropping the invariant metadata on dead argument loads, so
they weren't deleted.
Atomics still need to be fixed the same way. Also, apparently store
was never preserving dereferencable which should also be fixed.
Testing compiler-rt, a new assertion failure occurs when building
the GwpAsanTestObjects object. I'm uploading a reproducer to D70597.
This reverts commit 75188b01e9.
If there are DBG_VALUEs between phi and label (after phi and before label),
DBG_VALUE will block PHI lowering after the LABEL. Moving all DBG_VALUEs
after Labels in the function ScheduleDAGSDNodes::EmitSchedule to avoid
impacting PHI lowering.
before:
PHI
DBG_VALUE
LABEL
after: (move DBG_VALUE after label)
PHI
LABEL
DBG_VALUE
then: (phi lowering after label)
LABEL
COPY
DBG_VALUE
Fixes the issue: https://bugs.llvm.org/show_bug.cgi?id=43859
Differential Revision: https://reviews.llvm.org/D70597
This was moved in October 2018, but we don't appear to be using
this for vectors on any in tree target.
Moving it back simplifies D72794 so we can share the code for i32->f32.
This code is untested in tree because the "APFloat::semanticsPrecision(sem) >= SrcVT.getSizeInBits() - 1" check is false for most combinations for int and fp types except maybe i32 and f64. For that you would need i32 to be an illegal type, but f64 to be legal and have custom handling for legalizing the split sint_to_fp. The precision check itself was added in 2010 to fix a double rounding issue in the algorithm that would occur if the sint_to_fp was not able to do the conversion without rounding.
Differential Revision: https://reviews.llvm.org/D72728
Code in getRoot made the assumption that every node in PendingLoads
must always itself have a dependency on the current DAG root node.
After the changes in 04a8696, it turns out that this assumption no
longer holds true, causing wrong codegen in some cases (e.g. stores
after constrained FP intrinsics might get deleted).
To fix this, we now need to make sure that the TokenFactor created
by getRoot always includes the previous root, if there is no implicit
dependency already present.
The original getControlRoot code already has exactly this check,
so this patch simply reuses that code now for getRoot as well.
This fixes the regression.
NFC if no constrained FP intrinsic is present.
As mentioned by @nikic on rGef5debac4302, we can merge the guaranteed bottom zero bits from the shifted value, and then, if a min shift amount is known, zero out the bottom bits as well.
As mentioned by @nikic on rGef5debac4302 (although that was just about SHL), we can merge the guaranteed top zero bits from the shifted value, and then, if a min shift amount is known, zero out the top bits as well.
SHL tests / handling will be added in a follow up patch.
Summary:
be15dfa88f broke GlobalISel's usage of getSetCCInverse() which currently
appears to be limited to our out-of-tree backend. GlobalISel doesn't use
EVT's and isn't able to derive them from the information it has as it
doesn't distinguish between integer and floating point types (that
distinction is made by operations rather than values). Bring back the
bool version of getSetCCInverse() in a way that doesn't break the intent
of be15dfa88f but also allows GlobalISel to continue using it.
Reviewers: spatel, bogner, arichardson
Reviewed By: arichardson
Subscribers: rovka, hiraditya, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72309
Some target like arm/riscv with soft-float will have compiling crash when using -fno-unsafe-math-optimization option.
This patch will add the missing strict FP support to SoftenFloatRes_XINT_TO_FP.
Differential Revision: https://reviews.llvm.org/D72277
We need to ensure that fpexcept.strict nodes are not optimized away even if
the result is unused. To do that, we need to chain them into the block's
terminator nodes, like already done for PendingExcepts.
This patch adds two new lists of pending chains, PendingConstrainedFP and
PendingConstrainedFPStrict to hold constrained FP intrinsic nodes without
and with fpexcept.strict markers. This allows not only to solve the above
problem, but also to relax chains a bit further by no longer flushing all
FP nodes before a store or other memory access. (They are still flushed
before nodes with other side effects.)
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D72341
As detailed in https://blog.regehr.org/archives/1709 we don't make use of the known leading/trailing zeros for shifted values in cases where we don't know the shift amount value.
This patch adds support to SelectionDAG::ComputeKnownBits to use KnownBits::countMinTrailingZeros and countMinLeadingZeros to set the minimum guaranteed leading/trailing known zero bits.
Differential Revision: https://reviews.llvm.org/D72573
Custom legalization can produce MERGE_VALUES to return multiple
results. We can expand them immediately instead of leaving them
around for DAG combine to clean up.
Some of the simplest handlers just call TLI and if that fails,
they fall back to unrolling. For those just inline the TLI call
and share the unrolling call with the default case of Expand.
For ExpandFSUB and ExpandBITREVERSE so that its obvious they
don't return results sometimes and want to defer to LegalizeDAG.
Summary:
This always just used the same libcall as unordered, but the comparison predicate was different. This change appears to have been made when targets were given the ability to override the predicates. Before that they were hardcoded into the type legalizer. At that time we never inverted predicates and we handled ugt/ult/uge/ule compares by emitting an unordered check ORed with a ogt/olt/oge/ole checks. So only ordered needed an inverted predicate. Later ugt/ult/uge/ule were optimized to only call a single libcall and invert the compare.
This patch removes the ordered entries and just uses the inverting logic that is now present. This removes some odd things in both the Mips and WebAssembly code.
Reviewers: efriedma, ABataev, uweigand, cameron.mcinally, kpn
Reviewed By: efriedma
Subscribers: dschuff, sdardis, sbc100, arichardson, jgravelle-google, kristof.beyls, hiraditya, aheejin, sunfish, atanasyan, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72536
ONE is currently softened to OGT | OLT. But the libcalls for OGT and OLT libcalls will trigger an exception for QNAN. At least for X86 with libgcc. UEQ on the other hand uses UO | OEQ. The UO and OEQ libcalls will not trigger an exception for QNAN.
This patch changes ONE to use the inverse of the UEQ lowering. So we now produce O & UNE. Technically the existing behavior was correct for a signalling ONE, but since I don't know how to generate one of those from clang that seemed like something we can deal with later as we would need to fix other predicates as well. Also removing spurious exceptions seemed better than missing an exception.
There are also problems with quiet OGT/OLT/OLE/OGE, but those are harder to fix.
Differential Revision: https://reviews.llvm.org/D72477
This system wasn't very well designed for multi-result nodes. As
a consequence they weren't consistently registered in the
LegalizedNodes map leading to nodes being revisited for different
results.
I've removed the "Result" variable from the main LegalizeOp method
and used a SDNode* instead. The result number from the incoming
Op SDValue is only used for deciding which result to return to the
caller. When LegalizeOp is called it should always register a
legalized result for all of its results. Future calls for any other
result should be pulled for the LegalizedNodes map.
Legal nodes will now register all of their results in the map
instead of just the one we were called for.
The Expand and Promote handling to use a vector of results similar
to LegalizeDAG. Each of the new results is then re-legalized and
logged in the LegalizedNodes map for all of the Results for the
node being legalized. None of the handles register their own
results now. And none call ReplaceAllUsesOfValueWith now.
Custom handling now always passes result number 0 to LowerOperation.
This matches what LegalizeDAG does. Since the introduction of
STRICT nodes, I've encountered several issues with X86's custom
handling being called with an SDValue pointing at the chain and
our custom handlers using that to get a VT instead of result 0.
This should prevent us from having any more of those issues. On
return we will update the LegalizedNodes map for all results so
we shouldn't call the custom handler again for each result number.
I want to push SDNode* further into the Expand and Promote
handlers, but I've left that for a follow to keep this patch size
down. I've created a dummy SDValue(Node, 0) to keep the handlers
working.
Differential Revision: https://reviews.llvm.org/D72224
In D71841 we inverted the sense of the SDNode-level flag to ensure all nodes
default to potentially raising FP exceptions unless otherwise specified --
i.e. if we forget to propagate the flag somewhere, the effect is now only
lost performance, not incorrect code.
However, the related flag at the MI level still defaults to nodes not raising
FP exceptions unless otherwise specified. To be fully on the (conservatively)
safe side, we should invert that flag as well.
This patch does so by replacing MIFlag::FPExcept with MIFlag::NoFPExcept.
(Note that this does also introduce an incompatible change in the MIR format.)
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D72466
Only PPC seems to be using it, and only checks some simple cases and
doesn't distinguish between FP. Just switch to using LLT to simplify
use from GlobalISel.
If we're doing a compare that only tests the sign bit and only the sign bit is demanded, we can just bypass the node. This removes one of the blend dependencies in our v2i64->v2f32 uint_to_fp codegen on pre-sse4.2 targets.
Differential Revision: https://reviews.llvm.org/D72356
If we are extracting a chunk of a vector that's a fraction of an
operand of the concatenated vector operand, we can extract directly
from one of those original operands.
This is another suggestion from PR42024:
https://bugs.llvm.org/show_bug.cgi?id=42024#c2
But I'm not sure yet if it will make any difference on those patterns.
It seems to help a few existing AVX512 tests though.
Differential Revision: https://reviews.llvm.org/D72361
This is a positive combination as long as the NEG is NOT free,
as we are reducing the number of NEG from two to one.
Differential Revision: https://reviews.llvm.org/D72312
Summary:
Added MIRFormatter for target specific MIR formating and parsing with
immediate and custom pseudo source values. Target machine can subclass
MIRFormatter and implement custom logic for printing and parsing
immediate and custom pseudo source values for better readability.
* Target specific immediate mnemonic need to start with "." follows by
identifier string. When MIR parser sees immediate it will call target
specific parsing function.
* Custom pseudo source value need to start with custom follows by
double-quoted string. MIR parser will pass the quoted string to target
specific PSV parsing function.
* MIRFormatter have 2 helper functions to facilitate LLVM value printing
and parsing for custom PSV if they refers LLVM values.
Patch by Peng Guo
Reviewers: dsanders, arsenm
Reviewed By: dsanders
Subscribers: wdng, jvesely, nhaehnle, hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69836
Summary:
Added MIRFormatter for target specific MIR formating and parsing with
immediate and custom pseudo source values. Target machine can subclass
MIRFormatter and implement custom logic for printing and parsing
immediate and custom pseudo source values for better readability.
* Target specific immediate mnemonic need to start with "." follows by
identifier string. When MIR parser sees immediate it will call target
specific parsing function.
* Custom pseudo source value need to start with custom follows by
double-quoted string. MIR parser will pass the quoted string to target
specific PSV parsing function.
* MIRFormatter have 2 helper functions to facilitate LLVM value printing
and parsing for custom PSV if they refers LLVM values.
Reviewers: dsanders, arsenm
Reviewed By: dsanders
Subscribers: wdng, jvesely, nhaehnle, hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69836
Summary:
This patch adds intrinsics and ISelDAG nodes for
signed and unsigned fixed-point division:
llvm.sdiv.fix.*
llvm.udiv.fix.*
These intrinsics perform scaled division on two
integers or vectors of integers. They are required
for the implementation of the Embedded-C fixed-point
arithmetic in Clang.
Patch by: ebevhan
Reviewers: bjope, leonardchan, efriedma, craig.topper
Reviewed By: craig.topper
Subscribers: Ka-Ka, ilya, hiraditya, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70007
Summary:
Remove the restrictions that preventing "asm goto" from returning non-void
values. The values returned by "asm goto" are only valid on the "fallthrough"
path.
Reviewers: jyknight, nickdesaulniers, hfinkel
Reviewed By: jyknight, nickdesaulniers
Subscribers: rsmith, hiraditya, llvm-commits, cfe-commits, craig.topper, rnk
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D69876
This is possibly a small part towards solving PR42024:
https://bugs.llvm.org/show_bug.cgi?id=42024
The vectorizer is creating shuffles of concat like this:
%63 = shufflevector <4 x i64> %x, <4 x i64> undef, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 0, i32 1, i32 2, i32 3>
%64 = shufflevector <8 x i64> %63, <8 x i64> undef, <8 x i32> <i32 0, i32 4, i32 1, i32 5, i32 2, i32 6, i32 3, i32 7>
That might be fixable in the vectorizers, but we're not allowed to fold that into a single shuffle in instcombine,
so we should have a backend backstop to convert that into the likely simpler form:
%64 = shufflevector <4 x i64> %x, <4 x i64> undef, <8 x i32> <i32 0, i32 0, i32 1, i32 1, i32 2, i32 2, i32 3, i32 3>
Differential Revision: https://reviews.llvm.org/D72300
This patch adds widening which really just scalarizes because we don't have a strategy for the extra elements we would need to pad with.
Differential Revision: https://reviews.llvm.org/D72193
This isn't a functonal change since we also check the bit width is the
same and the input type is integer. This guarantees the input and
output type are the same. But passing the input type makes the code
more readable.
This is the DAG node for SIGN_EXTEND_INREG :
t21: v4i32 = sign_extend_inreg t18, ValueType:ch:v4i16
It has two operands. The first one is the value it want to extend, and the second
one is the type to specify how to extend the value. For this example, it means
that, it is signed extend the t18(v4i32) from v4i16 to v4i32. That is
the semantics of c code:
vector int foo(vector int m) {
return m << 16 >> 16;
}
And it could be any vector type that hardware support the operation, though
the type 'v4i16' is NOT legal for the target. When we are trying to combine
the srl + sra, what we did now is calling the TLI.isOperationLegal(), which
will also check the legality of the type. That doesn't make sense.
Differential Revision: https://reviews.llvm.org/D70230
The code here isn't great in all caess. Particularly v4f64->v4i32
on 64-bit AVX targets. But there is some improvement in some
configurations.
There's definitely some issues with computeNumSignBits with
X86ISD::STRICT_FCMP. As well as not being able to propagate sign
bits through merge_values nodes that get created during custom
legalization.
Previously, for vectors we created a vselect with a condition that
didn't match what the target wanted according to getSetCCResultType.
To make up for this, X86 had a special DAG combine to detect if
the condition was all sign bits and then insert its own truncate
or extend. By adding the extend/truncate here explicitly we can
avoid that.
ExpandStrictFPOp calls ExpandUINT_TO_FLOAT. Previously, ExpandUINT_TO_FLOAT
returned SDValue() if it wasn't able to handle and needed to unroll.
Then ExpandStrictFPOp would detect his SDValue() and do the unroll.
After this change, ExpandUINT_TO_FLOAT will directly call
UnrollStrictFPOp and return the unrolled result.
This patch attempts to peek through vectors based on the demanded bits/elt of a particular ISD::EXTRACT_VECTOR_ELT node, allowing us to avoid dependencies on ops that have no impact on the extract.
In particular this helps remove some unnecessary scalar->vector->scalar patterns.
The wasm shift patterns are annoying - @tlively has indicated that the wasm vector shift codegen are to be refactored in the near-term and isn't considered a major issue.
Reapplied after reversion at rL368660 due to PR42982 which was fixed at rGca7fdd41bda0.
Differential Revision: https://reviews.llvm.org/D65887
UpdateNodeOperands might CSE to another existing node. So we should make sure we're legalizing that node otherwise we might fail to hook up the operands properly. I've moved the result registration up to the caller to avoid having to pass both Result and Op into the functions where it might be confusing which is which.
This address 2 other issues pointed out in D71861.
Differential Revision: https://reviews.llvm.org/D72021
When the "disable-tail-calls" attribute was added, checks were added for
it in various backends. Now this code has proliferated, and it is
something the target is responsible for checking. Move that
responsibility back to the ISels (fast, global, and SD).
There's no major functionality change, except for targets that never
implemented this check.
This LLVM attribute was originally added in
d9699bc7bd (2015).
Reviewers: echristo, MaskRay
Differential Revision: https://reviews.llvm.org/D72118
The fold 'A - (A & (B - 1))' -> 'A & (0 - B)'
added in 8dab0a4a7d
is too specific. It should/can just be 'A - (A & B)' -> 'A & (~B)'
Even if we don't manage to fold `~` into B,
we have likely formed `ANDN` node.
Also, this way there's less similar-but-duplicate folds.
Name: X - (X & Y) -> X & (~Y)
%o = and i32 %X, %Y
%r = sub i32 %X, %o
=>
%n = xor i32 %Y, -1
%r = and i32 %X, %n
https://rise4fun.com/Alive/kOUl
See
https://bugs.llvm.org/show_bug.cgi?id=44448https://reviews.llvm.org/D71499
The fold 'A - (A & (B - 1))' -> 'A & (0 - B)'
added in 8dab0a4a7d
is too specific. It should just be 'A - (A & B)' -> 'A & (~B)',
but we currently fail to sink that '~' into `(B - 1)`.
Name: ~(X - 1) -> (0 - X)
%o = add i32 %X, -1
%r = xor i32 %o, -1
=>
%r = sub i32 0, %X
https://rise4fun.com/Alive/rjU
While we do manage to fold integer-typed IR in middle-end,
we can't do that for the main motivational case of pointers.
There is @llvm.ptrmask() intrinsic which may or may not be helpful,
but i'm not sure it is fully considered canonical yet,
not everything is fully aware of it likely.
Name: PR44448 ptr - (ptr & C) -> ptr & (~C)
%bias = and i32 %ptr, C
%r = sub i32 %ptr, %bias
=>
%r = and i32 %ptr, ~C
See
https://bugs.llvm.org/show_bug.cgi?id=44448https://reviews.llvm.org/D71499
While we do manage to fold integer-typed IR in middle-end,
we can't do that for the main motivational case of pointers.
There is @llvm.ptrmask() intrinsic which may or may not be helpful,
but i'm not sure it is fully considered canonical yet,
not everything is fully aware of it likely.
https://rise4fun.com/Alive/ZVdp
Name: ptr - (ptr & (alignment-1)) -> ptr & (0 - alignment)
%mask = add i64 %alignment, -1
%bias = and i64 %ptr, %mask
%r = sub i64 %ptr, %bias
=>
%highbitmask = sub i64 0, %alignment
%r = and i64 %ptr, %highbitmask
See
https://bugs.llvm.org/show_bug.cgi?id=44448https://reviews.llvm.org/D71499
The NoFPExcept bit in SDNodeFlags currently defaults to true, unlike all
other such flags. This is a problem, because it implies that all code that
transforms SDNodes without copying flags can introduce a correctness bug,
not just a missed optimization.
This patch changes the default to false. This makes it necessary to move
setting the (No)FPExcept flag for constrained intrinsics from the
visitConstrainedIntrinsic routine to the generic visit routine at the
place where the other flags are set, or else the intersectFlagsWith
call would erase the NoFPExcept flag again.
In order to avoid making non-strict FP code worse, whenever
SelectionDAGISel::SelectCodeCommon matches on a set of orignal nodes
none of which can raise FP exceptions, it will preserve this property
on all results nodes generated, by setting the NoFPExcept flag on
those result nodes that would otherwise be considered as raising
an FP exception.
To check whether or not an SD node should be considered as raising
an FP exception, the following logic applies:
- For machine nodes, check the mayRaiseFPException property of
the underlying MI instruction
- For regular nodes, check isStrictFPOpcode
- For target nodes, check a newly introduced isTargetStrictFPOpcode
The latter is implemented by reserving a range of target opcodes,
similarly to how memory opcodes are identified. (Note that there a
bit of a quirk in identifying target nodes that are both memory nodes
and strict FP nodes. To simplify the logic, right now all target memory
nodes are automatically also considered strict FP nodes -- this could
be fixed by adding one more range.)
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D71841
This was increasing the number of instructions when fsub was legalized
on AMDGPU with no signed zeros enabled. This fold should be guarded by
hasOneUse, and I don't think getNode should be doing that. The same
fold is already done as a regular combine through isNegatibleForFree.
This does require duplicating, even though isNegatibleForFree does
this combine already (and properly checks hasOneUse) to avoid one PPC
regression. In the regression, the outer fneg has nsz but the fsub
operand does not. isNegatibleForFree only sees the operand, and
doesn't see it's used from a nsz context. A nsz parameter needs to be
added and threaded through isNegatibleForFree to avoid this.
These operations are needed as building blocks for promoting so they
can't be promoted themselves.
This appeared to work because the fp_extend query type for operation
actions is the result type, not the input type so it never triggered
in the legalizer.
For fp_round, the vector op legalizer just ended up creating a
nop fp_extend that was elided by getNode, followed by a nop
fp_round that was also elided by getNode. This was followed by
a final fp_round from v4f32 back to vf416 which was CSEd to the
original node. Then legalize vector ops just believed that node
legalized to itself. LegalizeDAG took another crack at promoting
it, but didn't have a handler so just skipped it with a debug
message saying it wasn't promoted.
This patch just removes the operation actions to avoid this
non-sense. Found while trying to refactor LegalizeVectorOps to
handle multiple result nodes better.
This allows us to clean up some places that were peeking through
the MERGE_VALUES node after the call. By returning the SDValues
directly, we can clean that up.
Unfortunately, there are several call sites in AMDGPU that wanted
the MERGE_VALUES and now need to create their own.
This allows us to delete InlineAsm::Constraint_i workarounds in
SelectionDAGISel::SelectInlineAsmMemoryOperand overrides and
TargetLowering::getInlineAsmMemConstraint overrides.
They were introduced to X86 in r237517 to prevent crashes for
constraints like "=*imr". They were later copied to other targets.
SelectionDAG::transferDbgValues() can 'reattach' SDDbgValue from one to
another node, but doesn't change its source order. If the destination node has
the order greater than the SDDbgValue, there are two possible issues
revealed later:
* If debug info is attached to an instruction that is the first definition
of a register, this ends up with a def-after-use and the debug info
gets 'undef' later.
* If MIR has another definition of a register above the debug info,
the debug info may represent a source variable incorrectly because
it appears (significantly) before an instruction corresponded
to this debug info.
So, the patch changes the order of an SDDbgValue when it is moved
to a node with greater order.
Reviewers: dblaikie, jmorse, aprantl
Reviewed By: aprantl
Subscribers: aprantl, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71175
Fix several several additional problems with the int <-> FP conversion
logic both in common code and in the X86 target. In particular:
- The STRICT_FP_TO_UINT expansion emits a floating-point compare. This
compare can raise exceptions and therefore needs to be a strict compare.
I've made it signaling (even though quiet would also be correct) as
signaling is the more usual default for an LT. This code exists both
in common code and in the X86 target.
- The STRICT_UINT_TO_FP expansion algorithm was incorrect for strict mode:
it emitted two STRICT_SINT_TO_FP nodes and then used a select to choose one
of the results. This can cause spurious exceptions by the STRICT_SINT_TO_FP
that ends up not chosen. I've fixed the algorithm to use only a single
STRICT_SINT_TO_FP instead.
- The !isStrictFPEnabled logic in DoInstructionSelection would sometimes do
the wrong thing because it calls getOperationAction using the result VT.
But for some opcodes, incuding [SU]INT_TO_FP, getOperationAction needs to
be called using the operand VT.
- Remove some (obsolete) code in X86DAGToDAGISel::Select that would mutate
STRICT_FP_TO_[SU]INT to non-strict versions unnecessarily.
Reviewed by: craig.topper
Differential Revision: https://reviews.llvm.org/D71840
This moves the X86 specific transform from rL364407
into DAGCombiner to generically handle 'little to big' cases
(for example: extract_subvector(v2i64 bitcast(v16i8))). This
allows us to remove both the x86 implementation and the aarch64
bitcast(extract_subvector(bitcast())) combine.
Earlier patches that dealt with regressions initially exposed
by this patch:
rG5e5e99c041e4
rG0b38af89e2c0
Patch by: @RKSimon (Simon Pilgrim)
Differential Revision: https://reviews.llvm.org/D63815
Summary:
Without this check unnecessary FMA instructions are generated when the FSUB terms are reused.
This also has the side-effect that the same value is computed to different levels of precision, which can create undesirable effects if the results are used together in subsequent computation.
Reviewers: arsenm, nhaehnle, foad, tpr, dstuttard, spatel
Reviewed By: arsenm
Subscribers: jvesely, wdng, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71656
Summary:
We noticed in Julia that the sequence below no longer turned into
a sequence of FMA instructions in LLVM 7+, but it did in LLVM 6.
```
%29 = fmul contract <4 x double> %wide.load, %wide.load16
%30 = fmul contract <4 x double> %wide.load13, %wide.load17
%31 = fmul contract <4 x double> %wide.load14, %wide.load18
%32 = fmul contract <4 x double> %wide.load15, %wide.load19
%33 = fadd fast <4 x double> %vec.phi, %29
%34 = fadd fast <4 x double> %vec.phi10, %30
%35 = fadd fast <4 x double> %vec.phi11, %31
%36 = fadd fast <4 x double> %vec.phi12, %32
```
Unlike Clang, Julia doesn't set the `unsafe-fp-math=true` function
attribute, but rather emits more local instruction flags.
This partially undoes https://reviews.llvm.org/D46854 and if required I can try to minimize the test further.
Reviewers: spatel, mcberg2017
Reviewed By: spatel
Subscribers: chriselrod, merge_guards_bot, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71495
Add new intrinsics
llvm.experimental.constrained.minimum
llvm.experimental.constrained.maximum
as strict versions of llvm.minimum and llvm.maximum.
Includes SystemZ back-end support.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D71624
getTargetConstant prevents any optimizations from operating on the
value and basically says its already been iseled. But since we
want the index to be in a register, this isn't true.
Prior to this we were generating a vbroadcast with an immediate
argument which is illegal and was flagged by the expensive checks
bot.
This reverts commit 1f3dd83cc1, reapplying
commit bb1b0bc4e5.
The original commit failed on some builds seemingly due to the use of a
bracketed constructor with an std::array, i.e. `std::array<> arr({...})`.
Previously, LLVM had no functional way of performing casts inside of a
DIExpression(), which made salvaging cast instructions other than Noop
casts impossible. This patch enables the salvaging of casts by using the
DW_OP_LLVM_convert operator for SExt and Trunc instructions.
There is another issue which is exposed by this fix, in which fragment
DIExpressions (which are preserved more readily by this patch) for
values that must be split across registers in ISel trigger an assertion,
as the 'split' fragments extend beyond the bounds of the fragment
DIExpression causing an error. This patch also fixes this issue by
checking the fragment status of DIExpressions which are to be split, and
dropping fragments that are invalid.
Summary: Add calculation for elements in structures in getting uniform
base for the Gather/Scatter intrinsic.
Reviewers: craig.topper, c-rhodes, RKSimon
Subscribers: hiraditya, llvm-commits, annita.zhang, LuoYuanke
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71442
The caller will assert for nodes with more than 2 results unless
we return a null SDValue.
I tried to test this by copying an AArch64 test for ScalarizeVecOp_FP_ROUND.
While it did hit the assert and this commited fixed that. It also
hit a later problem that couldn't be fixed without adding strict
FP support to AArch64.
This started with adding a test to support get code coverage on
ScalarizeVecOp_UnaryOp_StrictFP by copying an existing AArch64 test
and using constrained sitofp/uitofp intrinsics.
This found 3 separate issues:
-ScalarizeVecOp_UnaryOp_StrictFP needs to do its own replacement
because the caller can't handle replacing multiple results.
-Missing integer promotion support for sitofp/uitofp
-Chain result not always assigned in ExpandLegalINT_TO_FP.
Committing them together so I can add the test case.
This is an alternate fix for the bug discussed in D70595.
This also includes minimal tests for other in-tree targets to show the problem more
generally.
We check the number of uses as a predicate for whether some value is free to negate,
but that use count can change as we rewrite the expression in getNegatedExpression().
So something that was marked free to negate during the cost evaluation phase becomes
not free to negate during the rewrite phase (or the inverse - something that was not
free becomes free). This can lead to a crash/assert because we expect that everything
in an expression that is negatible to be handled in the corresponding code within
getNegatedExpression().
This patch adds a hack to work-around the case where we probably no longer detect
that either multiply operand of an FMA isNegatibleForFree which is assumed to be
true when we started rewriting the expression.
Differential Revision: https://reviews.llvm.org/D70975
This is an alternate fix for the bug discussed in D70595.
This also includes minimal tests for other in-tree targets to show the problem more
generally.
We check the number of uses as a predicate for whether some value is free to negate,
but that use count can change as we rewrite the expression in getNegatedExpression().
So something that was marked free to negate during the cost evaluation phase becomes
not free to negate during the rewrite phase (or the inverse - something that was not
free becomes free). This can lead to a crash/assert because we expect that everything
in an expression that is negatible to be handled in the corresponding code within
getNegatedExpression().
This patch adds a hack to work-around the case where we probably no longer detect
that either multiply operand of an FMA isNegatibleForFree which is assumed to be
true when we started rewriting the expression.
Differential Revision: https://reviews.llvm.org/D70975
Summary:
Right now, DAGCombiner process the nodes in an iplementation defined order. This tends to be fragile as optimisation may or may not kick in depending on the traversal order.
This is part of a larger effort to get the DAGCombiner to process its node in topological order.
Reviewers: craig.topper, efriedma, RKSimon, lebedev.ri
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70921
of integers to floating point.
This includes some of Craig Topper's changes for promotion support from
D71130.
Differential Revision: https://reviews.llvm.org/D69275
It doesn't seem to do anything that SplitVecRes_StrictFPOp can't
do. SplitVecRes_StrictFPOp already handles nodes with a variable
number of arguments and a mix of scalar and vector arguments.
Summary:
To find potential opportunities to use getMemBasePlusOffset() I looked at
all ISD::ADD uses found with the regex getNode\(ISD::ADD,.+,.+Ptr
in lib/CodeGen/SelectionDAG. If this patch is accepted I will convert
the files in the individual backends too.
The motivation for this change is our out-of-tree CHERI backend
(https://github.com/CTSRD-CHERI/llvm-project). We use a separate register
type to store pointers (128-bit capabilities, which are effectively
unforgeable and monotonic fat pointers). These capabilities permit a
reduced set of operations and therefore use a separate ValueType (iFATPTR).
to represent pointers implemented as capabilities.
Therefore, we need to avoid using ISD::ADD for our patterns that operate
on pointers and need to use a function that chooses ISD::ADD or a new
ISD::PTRADD opcode depending on the value type.
We originally added a new DAG.getPointerAdd() function, but after this
patch series we can modify the implementation of getMemBasePlusOffset()
instead. Avoiding direct uses of ISD::ADD for pointer types will
significantly reduce the amount of assertion/instruction selection
failures for us in future upstream merges.
Reviewers: spatel
Reviewed By: spatel
Subscribers: merge_guards_bot, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71207
Simon Pilgrim