AttributeList::hasAttribute() is confusing, use clearer methods like
hasParamAttr()/hasRetAttr().
Add hasRetAttr() since it was missing from AttributeList.
This is recommit of the patch 16ff91ebcc,
reverted in 0c28a7c990 because it had
an error in call of getFastMathFlags (base type should be FPMathOperator
but not Instruction). The original commit message is duplicated below:
Clang has builtin function '__builtin_isnan', which implements C
library function 'isnan'. This function now is implemented entirely in
clang codegen, which expands the function into set of IR operations.
There are three mechanisms by which the expansion can be made.
* The most common mechanism is using an unordered comparison made by
instruction 'fcmp uno'. This simple solution is target-independent
and works well in most cases. It however is not suitable if floating
point exceptions are tracked. Corresponding IEEE 754 operation and C
function must never raise FP exception, even if the argument is a
signaling NaN. Compare instructions usually does not have such
property, they raise 'invalid' exception in such case. So this
mechanism is unsuitable when exception behavior is strict. In
particular it could result in unexpected trapping if argument is SNaN.
* Another solution was implemented in https://reviews.llvm.org/D95948.
It is used in the cases when raising FP exceptions by 'isnan' is not
allowed. This solution implements 'isnan' using integer operations.
It solves the problem of exceptions, but offers one solution for all
targets, however some can do the check in more efficient way.
* Solution implemented by https://reviews.llvm.org/D96568 introduced a
hook 'clang::TargetCodeGenInfo::testFPKind', which injects target
specific code into IR. Now only SystemZ implements this hook and it
generates a call to target specific intrinsic function.
Although these mechanisms allow to implement 'isnan' with enough
efficiency, expanding 'isnan' in clang has drawbacks:
* The operation 'isnan' is hidden behind generic integer operations or
target-specific intrinsics. It complicates analysis and can prevent
some optimizations.
* IR can be created by tools other than clang, in this case treatment
of 'isnan' has to be duplicated in that tool.
Another issue with the current implementation of 'isnan' comes from the
use of options '-ffast-math' or '-fno-honor-nans'. If such option is
specified, 'fcmp uno' may be optimized to 'false'. It is valid
optimization in general, but it results in 'isnan' always returning
'false'. For example, in some libc++ implementations the following code
returns 'false':
std::isnan(std::numeric_limits<float>::quiet_NaN())
The options '-ffast-math' and '-fno-honor-nans' imply that FP operation
operands are never NaNs. This assumption however should not be applied
to the functions that check FP number properties, including 'isnan'. If
such function returns expected result instead of actually making
checks, it becomes useless in many cases. The option '-ffast-math' is
often used for performance critical code, as it can speed up execution
by the expense of manual treatment of corner cases. If 'isnan' returns
assumed result, a user cannot use it in the manual treatment of NaNs
and has to invent replacements, like making the check using integer
operations. There is a discussion in https://reviews.llvm.org/D18513#387418,
which also expresses the opinion, that limitations imposed by
'-ffast-math' should be applied only to 'math' functions but not to
'tests'.
To overcome these drawbacks, this change introduces a new IR intrinsic
function 'llvm.isnan', which realizes the check as specified by IEEE-754
and C standards in target-agnostic way. During IR transformations it
does not undergo undesirable optimizations. It reaches instruction
selection, where is lowered in target-dependent way. The lowering can
vary depending on options like '-ffast-math' or '-ffp-model' so the
resulting code satisfies requested semantics.
Differential Revision: https://reviews.llvm.org/D104854
to `lib/CodeGen/CommandFlags.cpp`. It can replace
-x86-experimental-pref-loop-alignment=.
The loop alignment is only used by MachineBlockPlacement.
The implementation uses a new `llvm::TargetOptions` for now, as
an IR function attribute/module flags metadata may be overkill.
This is the llvm part of D106701.
Clang has builtin function '__builtin_isnan', which implements C
library function 'isnan'. This function now is implemented entirely in
clang codegen, which expands the function into set of IR operations.
There are three mechanisms by which the expansion can be made.
* The most common mechanism is using an unordered comparison made by
instruction 'fcmp uno'. This simple solution is target-independent
and works well in most cases. It however is not suitable if floating
point exceptions are tracked. Corresponding IEEE 754 operation and C
function must never raise FP exception, even if the argument is a
signaling NaN. Compare instructions usually does not have such
property, they raise 'invalid' exception in such case. So this
mechanism is unsuitable when exception behavior is strict. In
particular it could result in unexpected trapping if argument is SNaN.
* Another solution was implemented in https://reviews.llvm.org/D95948.
It is used in the cases when raising FP exceptions by 'isnan' is not
allowed. This solution implements 'isnan' using integer operations.
It solves the problem of exceptions, but offers one solution for all
targets, however some can do the check in more efficient way.
* Solution implemented by https://reviews.llvm.org/D96568 introduced a
hook 'clang::TargetCodeGenInfo::testFPKind', which injects target
specific code into IR. Now only SystemZ implements this hook and it
generates a call to target specific intrinsic function.
Although these mechanisms allow to implement 'isnan' with enough
efficiency, expanding 'isnan' in clang has drawbacks:
* The operation 'isnan' is hidden behind generic integer operations or
target-specific intrinsics. It complicates analysis and can prevent
some optimizations.
* IR can be created by tools other than clang, in this case treatment
of 'isnan' has to be duplicated in that tool.
Another issue with the current implementation of 'isnan' comes from the
use of options '-ffast-math' or '-fno-honor-nans'. If such option is
specified, 'fcmp uno' may be optimized to 'false'. It is valid
optimization in general, but it results in 'isnan' always returning
'false'. For example, in some libc++ implementations the following code
returns 'false':
std::isnan(std::numeric_limits<float>::quiet_NaN())
The options '-ffast-math' and '-fno-honor-nans' imply that FP operation
operands are never NaNs. This assumption however should not be applied
to the functions that check FP number properties, including 'isnan'. If
such function returns expected result instead of actually making
checks, it becomes useless in many cases. The option '-ffast-math' is
often used for performance critical code, as it can speed up execution
by the expense of manual treatment of corner cases. If 'isnan' returns
assumed result, a user cannot use it in the manual treatment of NaNs
and has to invent replacements, like making the check using integer
operations. There is a discussion in https://reviews.llvm.org/D18513#387418,
which also expresses the opinion, that limitations imposed by
'-ffast-math' should be applied only to 'math' functions but not to
'tests'.
To overcome these drawbacks, this change introduces a new IR intrinsic
function 'llvm.isnan', which realizes the check as specified by IEEE-754
and C standards in target-agnostic way. During IR transformations it
does not undergo undesirable optimizations. It reaches instruction
selection, where is lowered in target-dependent way. The lowering can
vary depending on options like '-ffast-math' or '-ffp-model' so the
resulting code satisfies requested semantics.
Differential Revision: https://reviews.llvm.org/D104854
This adds handling for two cases:
1. A scalable vector where the element type is promoted.
2. A scalable vector where the element count is odd (or more generally,
not divisble by the element count of the part type).
(Some element types still don't work; for example, <vscale x 2 x i128>,
or <vscale x 2 x fp128>.)
Differential Revision: https://reviews.llvm.org/D105591
Reland of 31859f896.
This change implements new DAG notes GLOBAL_GET/GLOBAL_SET, and
lowering methods for load and stores of reference types from IR
globals. Once the lowering creates the new nodes, tablegen pattern
matches those and converts them to Wasm global.get/set.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D104797
Reland of 31859f896.
This change implements new DAG notes GLOBAL_GET/GLOBAL_SET, and
lowering methods for load and stores of reference types from IR
globals. Once the lowering creates the new nodes, tablegen pattern
matches those and converts them to Wasm global.get/set.
Differential Revision: https://reviews.llvm.org/D104797
This ports the AArch64 SABD and USBD over to DAG Combine, where they can be
used by more backends (notably MVE in a follow-up patch). The matching code
has changed very little, just to handle legal operations and types
differently. It selects from (ABS (SUB (EXTEND a), (EXTEND b))), producing
a ubds/abdu which is zexted to the original type.
Differential Revision: https://reviews.llvm.org/D91937
This change implements new DAG notes GLOBAL_GET/GLOBAL_SET, and
lowering methods for load and stores of reference types from IR
globals. Once the lowering creates the new nodes, tablegen pattern
matches those and converts them to Wasm global.get/set.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D95425
Fixes getTypeConversion to return `TypeScalarizeScalableVector` when a scalable vector
type cannot be legalized by widening/splitting. When this is the method of legalization
found, getTypeLegalizationCost will return an Invalid cost.
The getMemoryOpCost, getMaskedMemoryOpCost & getGatherScatterOpCost functions already call
getTypeLegalizationCost and will now also return an Invalid cost for unsupported types.
Reviewed By: sdesmalen, david-arm
Differential Revision: https://reviews.llvm.org/D102515
Don't require a specific kind of IRBuilder for TargetLowering hooks.
This allows us to drop the IRBuilder.h include from TargetLowering.h.
Differential Revision: https://reviews.llvm.org/D103759
Use RuntimeLibcalls to get a common way to pick correct RTLIB::POWI_*
libcall for a given value type.
This includes a small refactoring of ExpandFPLibCall and
ExpandArgFPLibCall in SelectionDAGLegalize to share a bit of code,
plus adding an ExpandFPLibCall version that can be called directly
when expanding FPOWI/STRICT_FPOWI to ensure that we actually use
the same RTLIB::Libcall when expanding the libcall as we used when
checking the legality of such a call by doing a getLibcallName check.
Differential Revision: https://reviews.llvm.org/D103050
This patch extends the vector type-conversion and legalization capabilities of
scalable vector types.
Firstly, `vscale x 1` types now behave more like the corresponding `vscale x
2+` types. This enables the integer promotion legalization of extended scalable
types, such as the promotion of `<vscale x 1 x i5>` to `<vscale x 1 x i8>`.
These `vscale x 1` types are also now better handled by
`getVectorTypeBreakdown`, where what looks like older handling for 1-element
fixed-length vector types was spuriously updated to include scalable types.
Widening of scalable types is now better supported, by using `INSERT_SUBVECTOR`
to insert the smaller scalable vector "value" type into the wider scalable
vector "part" type. This allows AArch64 to pass and return `vscale x 1` types
by value by widening.
There are still cases where we are unable to legalize `vscale x 1` types, such
as where expansion would require splitting the vector in two.
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D102073
This is no-functional-change intended (NFC), but needed to allow
optimizer passes to use the API. See D98898 for a proposed usage
by SimplifyCFG.
I'm simplifying the code by removing the cl::opt. That was added
back with the original commit in D19488, but I don't see any
evidence in regression tests that it was used. Target-specific
overrides can use the usual patterns to adjust as necessary.
We could also restore that cl::opt, but it was not clear to me
exactly how to do it in the convoluted TTI class structure.
This patch introduces a new intrinsic @llvm.experimental.vector.splice
that constructs a vector of the same type as the two input vectors,
based on a immediate where the sign of the immediate distinguishes two
variants. A positive immediate specifies an index into the first vector
and a negative immediate specifies the number of trailing elements to
extract from the first vector.
For example:
@llvm.experimental.vector.splice(<A,B,C,D>, <E,F,G,H>, 1) ==> <B, C, D, E> ; index
@llvm.experimental.vector.splice(<A,B,C,D>, <E,F,G,H>, -3) ==> <B, C, D, E> ; trailing element count
These intrinsics support both fixed and scalable vectors, where the
former is lowered to a shufflevector to maintain existing behaviour,
although while marked as experimental the recommended way to express
this operation for fixed-width vectors is to use shufflevector. For
scalable vectors where it is not possible to express a shufflevector
mask for this operation, a new ISD node has been implemented.
This is one of the named shufflevector intrinsics proposed on the
mailing-list in the RFC at [1].
Patch by Paul Walker and Cullen Rhodes.
[1] https://lists.llvm.org/pipermail/llvm-dev/2020-November/146864.html
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D94708
This is a restricted version of the combine in `DAGCombiner::MatchLoadCombine`.
(See D27861)
This tries to recognize patterns like below (assuming a little-endian target):
```
s8* x = ...
s32 val = a[0] | (a[1] << 8) | (a[2] << 16) | (a[3] << 24)
->
s32 val = *((i32)a)
s8* x = ...
s32 val = a[3] | (a[2] << 8) | (a[1] << 16) | (a[0] << 24)
->
s32 val = BSWAP(*((s32)a))
```
(This patch also handles the big-endian target case as well, in which the first
example above has a BSWAP, and the second example above does not.)
To recognize the pattern, this searches from the last G_OR in the expression
tree.
E.g.
```
Reg Reg
\ /
OR_1 Reg
\ /
OR_2
\ Reg
.. /
Root
```
Each non-OR register in the tree is put in a list. Each register in the list is
then checked to see if it's an appropriate load + shift logic.
If every register is a load + potentially a shift, the combine checks if those
loads + shifts, when OR'd together, are equivalent to a wide load (possibly with
a BSWAP.)
To simplify things, this patch
(1) Only handles G_ZEXTLOADs (which appear to be the common case)
(2) Only works in a single MachineBasicBlock
(3) Only handles G_SHL as the bit twiddling to stick the small load into a
specific location
An IR example of this is here: https://godbolt.org/z/4sP9Pj (lifted from
test/CodeGen/AArch64/load-combine.ll)
At -Os on AArch64, this is a 0.5% code size improvement for CTMark/sqlite3,
and a 0.4% improvement for CTMark/7zip-benchmark.
Also fix a bug in `isPredecessor` which caused it to fail whenever `DefMI` was
the first instruction in the block.
Differential Revision: https://reviews.llvm.org/D94350
Add a triple for powerpcle-*-*.
This is a little-endian encoding of the 32-bit PowerPC ABI, useful in certain niche situations:
1) A loader such as the FreeBSD loader which will be loading a little endian kernel. This is required for PowerPC64LE to load properly in pseries VMs.
Such a loader is implemented as a freestanding ELF32 LSB binary.
2) Userspace emulation of a 32-bit LE architecture such as x86 on 64-bit hosts such as PowerPC64LE with tools like box86 requires having a 32-bit LE toolchain and library set, as they operate by translating only the main binary and switching to native code when making library calls.
3) The Void Linux for PowerPC project is experimenting with running an entire powerpcle userland.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D93918
This patch adds support for the fptoui.sat and fptosi.sat intrinsics,
which provide basically the same functionality as the existing fptoui
and fptosi instructions, but will saturate (or return 0 for NaN) on
values unrepresentable in the target type, instead of returning
poison. Related mailing list discussion can be found at:
https://groups.google.com/d/msg/llvm-dev/cgDFaBmCnDQ/CZAIMj4IBAAJ
The intrinsics have overloaded source and result type and support
vector operands:
i32 @llvm.fptoui.sat.i32.f32(float %f)
i100 @llvm.fptoui.sat.i100.f64(double %f)
<4 x i32> @llvm.fptoui.sat.v4i32.v4f16(half %f)
// etc
On the SelectionDAG layer two new ISD opcodes are added,
FP_TO_UINT_SAT and FP_TO_SINT_SAT. These opcodes have two operands
and one result. The second operand is an integer constant specifying
the scalar saturation width. The idea here is that initially the
second operand and the scalar width of the result type are the same,
but they may change during type legalization. For example:
i19 @llvm.fptsi.sat.i19.f32(float %f)
// builds
i19 fp_to_sint_sat f, 19
// type legalizes (through integer result promotion)
i32 fp_to_sint_sat f, 19
I went for this approach, because saturated conversion does not
compose well. There is no good way of "adjusting" a saturating
conversion to i32 into one to i19 short of saturating twice.
Specifying the saturation width separately allows directly saturating
to the correct width.
There are two baseline expansions for the fp_to_xint_sat opcodes. If
the integer bounds can be exactly represented in the float type and
fminnum/fmaxnum are legal, we can expand to something like:
f = fmaxnum f, FP(MIN)
f = fminnum f, FP(MAX)
i = fptoxi f
i = select f uo f, 0, i # unnecessary if unsigned as 0 = MIN
If the bounds cannot be exactly represented, we expand to something
like this instead:
i = fptoxi f
i = select f ult FP(MIN), MIN, i
i = select f ogt FP(MAX), MAX, i
i = select f uo f, 0, i # unnecessary if unsigned as 0 = MIN
It should be noted that this expansion assumes a non-trapping fptoxi.
Initial tests are for AArch64, x86_64 and ARM. This exercises all of
the scalar and vector legalization. ARM is included to test float
softening.
Original patch by @nikic and @ebevhan (based on D54696).
Differential Revision: https://reviews.llvm.org/D54749
The runtime library has two family library implementation for ppc_fp128 and fp128.
For IBM Long double(ppc_fp128), it is suffixed with 'l', i.e(sqrtl). For
IEEE Long double(fp128), it is suffixed with "ieee128" or "f128".
We miss to map several libcall for IEEE Long double.
Reviewed By: qiucf
Differential Revision: https://reviews.llvm.org/D91675
Sometimes people get minimal crash reports after a UBSAN incident. This change
tags each trap with an integer representing the kind of failure encountered,
which can aid in tracking down the root cause of the problem.
Add tests for this particular detail for x86 and arm (similar tests
already existed for x86_64 and aarch64).
The libssp implementation may be located in a separate DLL, and in
those cases, the references need to be in a .refptr stub, to avoid
needing to touch up code in the text section at runtime (which is
supported but inefficient for x86, and unsupported for arm).
Differential Revision: https://reviews.llvm.org/D92738
This patch implements out of line atomics for LSE deployment
mechanism. Details how it works can be found in llvm/docs/Atomics.rst
Options -moutline-atomics and -mno-outline-atomics to enable and disable it
were added to clang driver. This is clang and llvm part of out-of-line atomics
interface, library part is already supported by libgcc. Compiler-rt
support is provided in separate patch.
Differential Revision: https://reviews.llvm.org/D91157
Hook up legalizations for VECREDUCE_SEQ_FMUL. This is following up on the VECREDUCE_SEQ_FADD work from D90247.
Differential Revision: https://reviews.llvm.org/D90644
Add Legalization support for VECREDUCE_SEQ_FADD, so that we don't need to depend on ExpandReductionsPass.
Differential Revision: https://reviews.llvm.org/D90247
In certain places in llvm/lib/CodeGen we were relying upon the TypeSize
comparison operators when in fact the code was only ever expecting
either scalar values or fixed width vectors. I've changed some of these
places to use the equivalent scalar operator.
Differential Revision: https://reviews.llvm.org/D88482
This passes existing X86 test but I'm not sure if it handles all type
legalization cases it needs to.
Alternative to D89200
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D89222
I have introduced a new template PolySize class, where the template
parameter determines the type of quantity, i.e. for an element
count this is just an unsigned value. The ElementCount class is
now just a simple derivation of PolySize<unsigned>, whereas TypeSize
is more complicated because it still needs to contain the uint64_t
cast operator, since there are still many places in the code that
rely upon this implicit cast. As such the class also still needs
some of it's own operators.
I've tried to minimise the amount of code in the base PolySize
class, which led to a couple of changes:
1. In some places we were relying on '==' operator comparisons
between ElementCounts and the scalar value 1. I didn't put this
operator in the new PolySize class, and thought it was actually
clearer to use the isScalar() function instead.
2. I removed the isByteSized function and replaced it with calls
to isKnownMultipleOf(8).
I've also renamed NextPowerOf2 to be coefficientNextPowerOf2 so
that it's more consistent with coefficientDivideBy.
Differential Revision: https://reviews.llvm.org/D88409
When we know that a particular type is always going to be fixed
width we have so far been writing code like this:
getSizeInBits().getFixedSize()
Since we are doing this in quite a few places now it seems to make
sense to add a new helper function that allows us to replace
these calls with a single getFixedSizeInBits() call.
Differential Revision: https://reviews.llvm.org/D88649
After some recent upstream discussion we decided that it was best
to avoid having the / operator for both ElementCount and TypeSize,
since this could give the impression that these classes can be used
in the same way as basic integer integer types. However, division
for scalable types is a bit odd because we are only dividing the
minimum quantity by a value, as opposed to something like:
(MinSize * Vscale) / SomeValue
This is why when performing division it's important the caller
first establishes whether the operation makes sense, perhaps by
calling isKnownMultipleOf() prior to division. The caller must now
explictly call divideCoefficientBy() on the class to perform the
operation.
Differential Revision: https://reviews.llvm.org/D87700
An existing function Type::getScalarSizeInBits returns a uint64_t
instead of a TypeSize class because the caller is requesting a
scalar size, which cannot be scalable. This patch makes other
similar functions requesting a scalar size consistent with that,
thereby eliminating more than 1000 implicit TypeSize -> uint64_t
casts.
Differential revision: https://reviews.llvm.org/D87889
Clang emits (and (ctpop X), 1) for __builtin_parity. If ctpop
isn't natively supported by the target, this leads to poor codegen
due to the expansion of ctpop being more complex than what is needed
for parity.
This adds a DAG combine to convert the pattern to ISD::PARITY
before operation legalization. Type legalization is updated
to handled Expanding and Promoting this operation. If after type
legalization, CTPOP is supported for this type, LegalizeDAG will
turn it back into CTPOP+AND. Otherwise LegalizeDAG will emit a
series of shifts and xors followed by an AND with 1.
I've avoided vectors in this patch to avoid more legalization
complexity for this patch.
X86 previously had a custom DAG combiner for this. This is now
moved to Custom lowering for the new opcode. There is a minor
regression in vector-reduce-xor-bool.ll, but a follow up patch
can easily fix that.
Fixes PR47433
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D87209
This patch changes ElementCount so that the Min and Scalable
members are now private and can only be accessed via the get
functions getKnownMinValue() and isScalable(). In addition I've
added some other member functions for more commonly used operations.
Hopefully this makes the class more useful and will reduce the
need for calling getKnownMinValue().
Differential Revision: https://reviews.llvm.org/D86065
Matt Arsenault