The llvm.cond.loop intrinsic is semantically equivalent to a conditional
branch conditioned on ``pred`` to a basic block consisting only of an
unconditional branch to itself. Unlike such a branch, it is guaranteed
to use specific instructions. This allows an interrupt handler or
other introspection mechanism to straightforwardly detect whether
the program is currently spinning in the infinite loop and possibly
terminate the program if so. The intent is that this intrinsic may
be used as a more efficient alternative to a conditional branch to
a call to ``llvm.trap`` in circumstances where the loop detection
is guaranteed to be present. This construct has been experimentally
determined to be executed more efficiently (when the branch is not taken)
than a conditional branch to a trap instruction on AMD and older Intel
microarchitectures, and is also more code size efficient by avoiding the
need to emit a trap instruction and possibly a long branch instruction.
On i386 and x86_64, the infinite loop is guaranteed to consist of a short
conditional branch instruction that branches to itself. Specifically,
the first byte of the instruction will be between 0x70 and 0x7F, and
the second byte will be 0xFE.
Part of this RFC:
https://discourse.llvm.org/t/rfc-optimizing-conditional-traps/89456
Reviewers: arsenm, RKSimon, fmayer, vitalybuka
Pull Request: https://github.com/llvm/llvm-project/pull/177686
There are target intrinsics that logically require two MMOs, such as
llvm.amdgcn.global.load.lds, which is a copy from global memory to LDS,
so there's both a load and a store to different addresses.
Add an overload of getTgtMemIntrinsic that produces intrinsic info in a
vector, and implement it in terms of the existing (now protected)
overload.
GlobalISel and SelectionDAG paths are updated to support multiple MMOs.
The main part of this change is supporting multiple MMOs in
MemIntrinsicNodes.
Converting the backends to using the new overload is a fairly mechanical step
that is done in a separate change in the hope that that allows reducing merging
pains during review and for downstreams. A later change will then enable
using multiple MMOs in AMDGPU.
Add support for `__builtin_stack_address` builtin. The semantics match
those of GCC's builtin with the same name.
`__builtin_stack_address` returns the starting address of the stack
region that may be used by called functions. It may or may not include
the space used for on-stack arguments passed to a callee (See [GCC
Bug/121013](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121013)).
Fixes#82632.
This PR implements the first change outlined in
https://discourse.llvm.org/t/rfc-allow-non-constant-offsets-in-llvm-vector-splice/88974?u=lukel
In order to allow non-immediate offsets in the llvm.vector.splice
intrinsic, we need to separate out the "shift left" and "shift right"
modes into two separate intrinsics, which were previously determined by
whether or not the offset is positive or negative.
The description in the LangRef has also been reworded in terms of
sliding elements left or right and extracting either the upper or lower
half as opposed to extracting from a certain index, which brings it
inline with the definition of `llvm.fshr.*`/`llvm.fshl.*`.
This patch teaches AutoUpgrade.cpp to upgrade the old intrinsics into
their new equivalent one based on their offset, so existing uses of
vector.splice should still work.
Uses of llvm.vector.splice in `llvm/test/CodeGen` haven't been replaced
in this PR to keep the diff small and kick the tyres on the AutoUpgrader
a bit. I planned to do this in a follow up NFC but can include it in
this PR if reviewers prefer.
Similarly the shuffle costing kind `SK_Splice` has just been kept the
same for now, to be split into `SK_SpliceLeft` and `SK_SpliceRight`
later.
In line with a std proposal to introduce the llvm.clmul family of
intrinsics corresponding to carry-less multiply operations. This work
builds upon 727ee7e ([APInt] Introduce carry-less multiply primitives),
and follow-up patches will introduce custom-lowering on supported
targets, replacing target-specific clmul intrinsics.
Testing is done on the RISC-V target, which should be sufficient to
prove that the intrinsics work, since no RISC-V specific lowering has
been added.
Ref: https://isocpp.org/files/papers/P3642R3.html
Co-authored-by: Craig Topper <craig.topper@sifive.com>
The RISC-V P extension adds an instruction equivalent to
__builtin_clrsb. AArch64 has a similar instruction that we currently fail to
select when using the builtin.
This patch adds a combine based on the canonical version of the pattern
emitted by clang for the builtin, (add (ctlz (xor x, (sra x, bw-1)))),
-1). I'm starting the combine at the ctlz because the outer add can
easily be combined into other nodes obscuring the full pattern. So we
generate (add (ctls x), 1) and hope the add will be combined away.
I've also added a combine for the pattern AArch64 recognizes
(ctlz_zero_undef (or (shl (xor x, (sra x, bw-1)), 1), 1)).
I've only enabled the combines when the target has a Legal or Custom
action for the operation, taking into account type promotion. We
can relax this in the future by adding a default expansion to
LegalizeDAG and adding more type legalization rules.
This intrinsic emits a BFD_RELOC_NONE relocation at the point of call,
which allows optimizations and languages to explicitly pull in symbols
from static libraries without there being any code or data that has an
effectual relocation against such a symbol.
See issue #146159 for context.
This patch introduces SDNodeFlags::InBounds, to show that an ISD::PTRADD SDNode
implements an inbounds getelementptr operation (i.e., the pointer operand is in
bounds wrt. an allocated object it is based on, and the arithmetic does not
change that). The flag is set in the DAG construction when lowering inbounds
GEPs.
Inbounds information is useful in the ISel when selecting memory instructions
that perform address computations whose intermediate steps must be in the same
memory region as the final result. Follow-up patches to propagate the flag in
DAGCombines and to use it when lowering AMDGPU's flat memory instructions,
where the immediate offset must not affect the memory aperture of the address
(similar to this GISel patch: #153001), are planned.
This mirrors #150900, which has introduced a similar flag in GlobalISel.
This patch supersedes #131862, which previously attempted to introduce an
SDNodeFlags::InBounds flag. The difference between this PR and #131862 is that
there is now an ISD::PTRADD opcode (PR #140017) and the InBounds flag is only
defined to apply to ISD::PTRADD DAG nodes. It is therefore unambiguous that
in-bounds-ness refers to a memory object into which the left operand of the
PTRADD node points (in contrast to #131862, where InBounds would have applied
to commutative ISD::ADD nodes, so that the semantics would be more difficult to
reason about).
For SWDEV-516125.
Reland #161355, after fixing up the cross-projects-tests for the wasm
simd intrinsics.
Original commit message:
Lower v4f32 and v2f64 fmuladd calls to relaxed_madd instructions.
If we have FP16, then lower v8f16 fmuladds to FMA.
I've introduced an ISD node for fmuladd to maintain the rounding
ambiguity through legalization / combine / isel.
Lower v4f32 and v2f64 fmuladd calls to relaxed_madd instructions.
If we have FP16, then lower v8f16 fmuladds to FMA.
I've introduced an ISD node for fmuladd to maintain the rounding
ambiguity through legalization / combine / isel.
An alternative approach to #149732 , which sorts the DAG before dumping
it. That approach runs a risk of altering the codegen result as we don't
know if any of the downstream DAG users relies on the node ID, which was
updated as part of the sorting.
The new method proposed by this PR does not update the node ID or any of
the DAG's internal states: the newly added
`SelectionDAG::getTopologicallyOrderedNodes` is a const member function
that returns a list of all nodes in their topological order.
It can be unsafe to load a vector from an address and write a vector to
an address if those two addresses have overlapping lanes within a
vectorised loop iteration.
This PR adds intrinsics designed to create a mask with lanes disabled if
they overlap between the two pointer arguments, so that only safe lanes
are loaded, operated on and stored. The `loop.dependence.war.mask`
intrinsic represents cases where the store occurs after the load, and
the opposite for `loop.dependence.raw.mask`. The distinction between
write-after-read and read-after-write is important, since the ordering
of the read and write operations affects if the chain of those
instructions can be done safely.
Along with the two pointer parameters, the intrinsics also take an
immediate that represents the size in bytes of the vector element types.
This will be used by #100579.
Split out from https://github.com/llvm/llvm-project/pull/150248:
Specify that the argument of lifetime.start/lifetime.end is ignored and
will be removed in the future.
Remove lifetime size handling from SDAG. The size was previously
discarded during isel, so was always ignored for stack coloring anyway.
Where necessary, obtain the size of the full frame index.
After https://github.com/llvm/llvm-project/pull/149310 we are guaranteed
that the argument is an alloca, so we don't need to look at underlying
objects (which was not a correct thing to do anyway).
This also drops the offset argument for lifetime nodes in SDAG. The
offset is fixed to zero now. (Peculiarly, while SDAG pretended to have
an offset, it just gets silently dropped during selection.)
We have recently added the partial_reduce_smla and partial_reduce_umla
nodes to represent Acc += ext(b) * ext(b) where the two extends have to
have the same source type, and have the same extend kind.
For riscv64 w/zvqdotq, we have the vqdot and vqdotu instructions which
correspond to the existing nodes, but we also have vqdotsu which
represents the case where the two extends are sign and zero respective
(i.e. not the same type of extend).
This patch adds a partial_reduce_sumla node which has sign extension for
A, and zero extension for B. The addition is somewhat mechanical.
This opcode represents the addition of a pointer value (first operand)
and an integer offset (second operand). PTRADD nodes are only generated
if the TargetMachine opts in by overriding
TargetMachine::shouldPreservePtrArith().
The PTRADD node and respective visitPTRADD() function were adapted by
@rgwott from the CHERI/Morello LLVM tree.
Original authors: @davidchisnall, @jrtc27, @arichardson.
The changes in this PR were extracted from PR #105669.
---------
Co-authored-by: David Chisnall <github@theravensnest.org>
Co-authored-by: Jessica Clarke <jrtc27@jrtc27.com>
Co-authored-by: Alexander Richardson <alexrichardson@google.com>
Co-authored-by: Rodolfo Wottrich <rodolfo.wottrich@arm.com>
For now expansion still happens in SelectionDAGBuilder when
GET_ACTIVE_LANE_MASK is not legal on the target.
This patch also includes changes in AArch64ISelLowering to replace
handling of the get.active.lane.mask intrinsic to use the ISD node.
Tablegen patterns are added which match to whilelo for scalable types.
A follow up change will add support for more types to be lowered to
GET_ACTIVE_LANE_MASK by allowing splitting of the node.
It is used to mark a value that we are sure that it is not some fcType.
The examples include:
* An arguments of a function is marked with nofpclass
* Output value of an intrinsic can be sure to not be some type
So that the following operation can make some assumptions.
This patch adds support for LLVM IR atomicrmw `fmaximum` and `fminimum`
instructions.
These mirror the `llvm.maximum.*` and `llvm.minimum.*` instructions, but
are atomic and use IEEE754 2019 handling for NaNs, which is different to
`fmax` and `fmin`. See:
https://llvm.org/docs/LangRef.html#llvm-minimum-intrinsic
for more details.
Future changes will allow this LLVM IR to be lowered to specialised
assembler instructions on suitable targets, such as AArch64.
This patch adds support for LLVM IR atomicrmw `fmaximum` and `fminimum`
instructions.
These mirror the `llvm.maximum.*` and `llvm.minimum.*` instructions, but
are atomic and use IEEE754 2019 handling for NaNs, which is different to
`fmax` and `fmin`. See:
https://llvm.org/docs/LangRef.html#llvm-minimum-intrinsic
for more details.
Future changes will allow this LLVM IR to be lowered to specialised
assembler instructions on suitable targets, such as AArch64.
It is used to mark a value that we are sure that it is not some fcType.
The examples include:
* An arguments of a function is marked with nofpclass
* Output value of an intrinsic can be sure to not be some type
So that the following operation can make some assumptions.
---------
Co-authored-by: Your Name <you@example.com>
Add signed and unsigned PARTIAL_REDUCE_MLA ISD nodes. Add command line
argument (aarch64-enable-partial-reduce-nodes) that indicates whether the
intrinsic experimental_vector_partial_ reduce_add will be transformed
into the new ISD node. Lowering with the new ISD nodes will, for now,
always be done as an expand.
This adds the `llvm.sincospi` intrinsic, legalization, and lowering
(mostly reusing the lowering for sincos and frexp).
The `llvm.sincospi` intrinsic takes a floating-point value and returns
both the sine and cosine of the value multiplied by pi. It computes the
result more accurately than the naive approach of doing the
multiplication ahead of time, especially for large input values.
```
declare { float, float } @llvm.sincospi.f32(float %Val)
declare { double, double } @llvm.sincospi.f64(double %Val)
declare { x86_fp80, x86_fp80 } @llvm.sincospi.f80(x86_fp80 %Val)
declare { fp128, fp128 } @llvm.sincospi.f128(fp128 %Val)
declare { ppc_fp128, ppc_fp128 } @llvm.sincospi.ppcf128(ppc_fp128 %Val)
declare { <4 x float>, <4 x float> } @llvm.sincospi.v4f32(<4 x float> %Val)
```
Currently, the default lowering of this intrinsic relies on the
`sincospi[f|l]` functions being available in the target's runtime (e.g.
libc).
This adds the `llvm.modf` intrinsic, legalization, and lowering (mostly
reusing the lowering for sincos and frexp).
The `llvm.modf` intrinsic takes a floating-point value and returns both
the integral and fractional parts (as a struct).
```
declare { float, float } @llvm.modf.f32(float %Val)
declare { double, double } @llvm.modf.f64(double %Val)
declare { x86_fp80, x86_fp80 } @llvm.modf.f80(x86_fp80 %Val)
declare { fp128, fp128 } @llvm.modf.f128(fp128 %Val)
declare { ppc_fp128, ppc_fp128 } @llvm.modf.ppcf128(ppc_fp128 %Val)
declare { <4 x float>, <4 x float> } @llvm.modf.v4f32(<4 x float> %Val)
```
This corresponds to the libm `modf` function but returns multiple values
in a struct (rather than take output pointers), which makes it easier to
vectorize.
Based on feedback from the clastb codegen PR, I'm refactoring basic codegen for the vector.extract.last.active intrinsic to lower to an ISD node in SelectionDAGBuilder then expand in LegalizeVectorOps, instead of doing everything in the builder.
The new ISD node (vector_find_last_active) only covers finding the index of the last active element of the mask, and extracting the element + handling passthru is left to existing ISD nodes.
Original commit: 19c8475871faee5ebb06281034872a85a2552675
Multiple 2-stage sanitizer buildbots were reporting failures, the issue
has been addressed separately in 29246a92aee87e86cbc2bb64ee520d7385644f34.
Crashes on ARM builds
https://lab.llvm.org/buildbot/#/builders/85/builds/2548
```
DAGCombiner.cpp:16157: SDValue (anonymous
namespace)::DAGCombiner::visitFREEZE(SDNode *):
Assertion `DAG.isGuaranteedNotToBeUndefOrPoison(R,
false) && "Can't create node that may be
undef/poison!"' failed.
```
Issue #114648
This reverts commit 19c8475871faee5ebb06281034872a85a2552675.
This change is part of this proposal:
https://discourse.llvm.org/t/rfc-all-the-math-intrinsics/78294
Based on example PR #96222 and fix PR #101268, with some differences due
to 2-arg intrinsic and intermediate refactor (RuntimeLibCalls.cpp).
- Add llvm.experimental.constrained.atan2 - Intrinsics.td,
ConstrainedOps.def, LangRef.rst
- Add to ISDOpcodes.h and TargetSelectionDAG.td, connect to intrinsic in
BasicTTIImpl.h, and LibFunc_ in SelectionDAGBuilder.cpp
- Update LegalizeDAG.cpp, LegalizeFloatTypes.cpp, LegalizeVectorOps.cpp,
and LegalizeVectorTypes.cpp
- Update isKnownNeverNaN in SelectionDAG.cpp
- Update SelectionDAGDumper.cpp
- Update libcalls - RuntimeLibcalls.def, RuntimeLibcalls.cpp
- TargetLoweringBase.cpp - Expand for vectors, promote f16
- X86ISelLowering.cpp - Expand f80, promote f32 to f64 for MSVC
Part 4 for Implement the atan2 HLSL Function #70096.
This patch is part of a set of patches that add an `-fextend-lifetimes`
flag to clang, which extends the lifetimes of local variables and
parameters for improved debuggability. In addition to that flag, the
patch series adds a pragma to selectively disable `-fextend-lifetimes`,
and an `-fextend-this-ptr` flag which functions as `-fextend-lifetimes`
for this pointers only. All changes and tests in these patches were
written by Wolfgang Pieb (@wolfy1961), while Stephen Tozer (@SLTozer)
has handled review and merging. The extend lifetimes flag is intended to
eventually be set on by `-Og`, as discussed in the RFC
here:
https://discourse.llvm.org/t/rfc-redefine-og-o1-and-add-a-new-level-of-og/72850
This patch implements a new intrinsic instruction in LLVM,
`llvm.fake.use` in IR and `FAKE_USE` in MIR, that takes a single operand
and has no effect other than "using" its operand, to ensure that its
operand remains live until after the fake use. This patch does not emit
fake uses anywhere; the next patch in this sequence causes them to be
emitted from the clang frontend, such that for each variable (or this) a
fake.use operand is inserted at the end of that variable's scope, using
that variable's value. This patch covers everything post-frontend, which
is largely just the basic plumbing for a new intrinsic/instruction,
along with a few steps to preserve the fake uses through optimizations
(such as moving them ahead of a tail call or translating them through
SROA).
Co-authored-by: Stephen Tozer <stephen.tozer@sony.com>
C23 introduced new functions fminimum_num and fmaximum_num, and they
follow the minimumNumber and maximumNumber of IEEE754-2019. Let's
introduce new intrinsics to support them.
This patch introduces support only support for scalar values. The
support of
vector (vp, vp.reduce, vector.reduce),
experimental.constrained
will be added in future patches.
With this patch, MIPSr6 and LoongArch can work out of box with
fcanonical and fmax/fmin.
Aarch64/PowerPC64 can use the same login as MIPSr6 and LoongArch, while
they have no fcanonical support yet.
I will add it in future patches.
The FMIN/FMAX of RISC-V instructions follows the
minimumNumber/maximumNumber of IEEE754-2019. We can just add it in
future patch.
Background
https://discourse.llvm.org/t/rfc-fix-llvm-min-f-and-llvm-max-f-intrinsics/79735
Currently we have fminnum/fmaxnum, which have different behavior on
different platform for NUM vs sNaN:
1) Fallback to fmin(3)/fmax(3): return qNaN.
2) ARM64/ARM32+Neon: same as libc.
3) MIPSr6/LoongArch/RISC-V: return NUM.
And the fix of fminnum/fmaxnum to follow minNUM/maxNUM of IEEE754-2008
will submit as separated patches.
A truncate is considered saturated if no additional conversion is required between the target and return values. If the target is saturated when attempting to truncate from a vector, there is an opportunity to optimize it.
Previously, each architecture had its own attempt at optimization, leading to redundant code. This patch implements common logic by introducing three new ISDs:
`ISD::TRUNCATE_SSAT_S`: When the operand is a signed value and the range of values matches the range of signed values of the destination type.
`ISD::TRUNCATE_SSAT_U`: When the operand is a signed value and the range of values matches the range of unsigned values of the destination type.
`ISD::TRUNCATE_USAT_U`: When the operand is an unsigned value and the range of values matches the range of unsigned values of the destination type.
These ISDs indicate a saturated truncate.
Fixes https://github.com/llvm/llvm-project/issues/85903
This PR adds a new vector intrinsic `@llvm.experimental.vector.compress`
to "compress" data within a vector based on a selection mask, i.e., it
moves all selected values (i.e., where `mask[i] == 1`) to consecutive
lanes in the result vector. A `passthru` vector can be provided, from
which remaining lanes are filled.
The main reason for this is that the existing
`@llvm.masked.compressstore` has very strong constraints in that it can
only write values that were selected, resulting in guard branches for
all targets except AVX-512 (and even there the AMD implementation is
_very_ slow). More instruction sets support "compress" logic, but only
within registers. So to store the values, an additional store is needed.
But this combination is likely significantly faster on many target as it
avoids branches.
In follow up PRs, my plan is to add target-specific lowerings for x86,
SVE, and possibly RISCV. I also want to combine this with a store
instruction, as this is probably a common case and we can avoid some
memory writes in that case.
See [discussion in
forum](https://discourse.llvm.org/t/new-intrinsic-for-masked-vector-compress-without-store/78663)
for initial discussion on the design.
