Commit Graph

837 Commits

Author SHA1 Message Date
Cullen Rhodes 2ddf795e8c Reland "[CodeGen][AArch64] Support arm_sve_vector_bits attribute"
This relands D85743 with a fix for test
CodeGen/attr-arm-sve-vector-bits-call.c that disables the new pass
manager with '-fno-experimental-new-pass-manager'. Test was failing due
to IR differences with the new pass manager which broke the Fuchsia
builder [1]. Reverted in 2e7041f.

[1] http://lab.llvm.org:8011/builders/fuchsia-x86_64-linux/builds/10375

Original summary:

This patch implements codegen for the 'arm_sve_vector_bits' type
attribute, defined by the Arm C Language Extensions (ACLE) for SVE [1].
The purpose of this attribute is to define vector-length-specific (VLS)
versions of existing vector-length-agnostic (VLA) types.

VLSTs are represented as VectorType in the AST and fixed-length vectors
in the IR everywhere except in function args/return. Implemented in this
patch is codegen support for the following:

  * Implicit casting between VLA <-> VLS types.
  * Coercion of VLS types in function args/return.
  * Mangling of VLS types.

Casting is handled by the CK_BitCast operation, which has been extended
to support the two new vector kinds for fixed-length SVE predicate and
data vectors, where the cast is implemented through memory rather than a
bitcast which is unsupported. Implementing this as a normal bitcast
would require relaxing checks in LLVM to allow bitcasting between
scalable and fixed types. Another option was adding target-specific
intrinsics, although codegen support would need to be added for these
intrinsics. Given this, casting through memory seemed like the best
approach as it's supported today and existing optimisations may remove
unnecessary loads/stores, although there is room for improvement here.

Coercion of VLSTs in function args/return from fixed to scalable is
implemented through the AArch64 ABI in TargetInfo.

The VLA and VLS types are defined by the ACLE to map to the same
machine-level SVE vectors. VLS types are mangled in the same way as:

  __SVE_VLS<typename, unsigned>

where the first argument is the underlying variable-length type and the
second argument is the SVE vector length in bits. For example:

  #if __ARM_FEATURE_SVE_BITS==512
  // Mangled as 9__SVE_VLSIu11__SVInt32_tLj512EE
  typedef svint32_t vec __attribute__((arm_sve_vector_bits(512)));
  // Mangled as 9__SVE_VLSIu10__SVBool_tLj512EE
  typedef svbool_t pred __attribute__((arm_sve_vector_bits(512)));
  #endif

The latest ACLE specification (00bet5) does not contain details of this
mangling scheme, it will be specified in the next revision.  The
mangling scheme is otherwise defined in the appendices to the Procedure
Call Standard for the Arm Architecture, see [2] for more information.

[1] https://developer.arm.com/documentation/100987/latest
[2] https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst#appendix-c-mangling

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D85743
2020-08-28 15:57:09 +00:00
JF Bastien 82d29b397b Add an unsigned shift base sanitizer
It's not undefined behavior for an unsigned left shift to overflow (i.e. to
shift bits out), but it has been the source of bugs and exploits in certain
codebases in the past. As we do in other parts of UBSan, this patch adds a
dynamic checker which acts beyond UBSan and checks other sources of errors. The
option is enabled as part of -fsanitize=integer.

The flag is named: -fsanitize=unsigned-shift-base
This matches shift-base and shift-exponent flags.

<rdar://problem/46129047>

Differential Revision: https://reviews.llvm.org/D86000
2020-08-27 19:50:10 -07:00
Cullen Rhodes 2e7041fdc2 Revert "[CodeGen][AArch64] Support arm_sve_vector_bits attribute"
Test CodeGen/attr-arm-sve-vector-bits-call.c is failing on some builders
[1][2]. Reverting whilst I investigate.

[1] http://lab.llvm.org:8011/builders/fuchsia-x86_64-linux/builds/10375
[2] https://luci-milo.appspot.com/p/fuchsia/builders/ci/clang-linux-x64/b8870800848452818112

This reverts commit 42587345a3.
2020-08-27 21:31:05 +00:00
Cullen Rhodes 42587345a3 [CodeGen][AArch64] Support arm_sve_vector_bits attribute
This patch implements codegen for the 'arm_sve_vector_bits' type
attribute, defined by the Arm C Language Extensions (ACLE) for SVE [1].
The purpose of this attribute is to define vector-length-specific (VLS)
versions of existing vector-length-agnostic (VLA) types.

VLSTs are represented as VectorType in the AST and fixed-length vectors
in the IR everywhere except in function args/return. Implemented in this
patch is codegen support for the following:

  * Implicit casting between VLA <-> VLS types.
  * Coercion of VLS types in function args/return.
  * Mangling of VLS types.

Casting is handled by the CK_BitCast operation, which has been extended
to support the two new vector kinds for fixed-length SVE predicate and
data vectors, where the cast is implemented through memory rather than a
bitcast which is unsupported. Implementing this as a normal bitcast
would require relaxing checks in LLVM to allow bitcasting between
scalable and fixed types. Another option was adding target-specific
intrinsics, although codegen support would need to be added for these
intrinsics. Given this, casting through memory seemed like the best
approach as it's supported today and existing optimisations may remove
unnecessary loads/stores, although there is room for improvement here.

Coercion of VLSTs in function args/return from fixed to scalable is
implemented through the AArch64 ABI in TargetInfo.

The VLA and VLS types are defined by the ACLE to map to the same
machine-level SVE vectors. VLS types are mangled in the same way as:

  __SVE_VLS<typename, unsigned>

where the first argument is the underlying variable-length type and the
second argument is the SVE vector length in bits. For example:

  #if __ARM_FEATURE_SVE_BITS==512
  // Mangled as 9__SVE_VLSIu11__SVInt32_tLj512EE
  typedef svint32_t vec __attribute__((arm_sve_vector_bits(512)));
  // Mangled as 9__SVE_VLSIu10__SVBool_tLj512EE
  typedef svbool_t pred __attribute__((arm_sve_vector_bits(512)));
  #endif

The latest ACLE specification (00bet5) does not contain details of this
mangling scheme, it will be specified in the next revision.  The
mangling scheme is otherwise defined in the appendices to the Procedure
Call Standard for the Arm Architecture, see [2] for more information.

[1] https://developer.arm.com/documentation/100987/latest
[2] https://github.com/ARM-software/abi-aa/blob/master/aapcs64/aapcs64.rst#appendix-c-mangling

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D85743
2020-08-27 15:11:58 +00:00
Christopher Tetreault 19e883fc59 [SVE] Remove calls to VectorType::getNumElements from clang
Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D82582
2020-08-26 11:12:26 -07:00
Bevin Hansson 577f8b157a [Fixed Point] Add codegen for fixed-point shifts.
This patch adds codegen to Clang for fixed-point shift
operations.

Reviewed By: leonardchan

Differential Revision: https://reviews.llvm.org/D83294
2020-08-24 14:37:16 +02:00
Bevin Hansson 808ac54645 [Fixed Point] Use FixedPointBuilder to codegen fixed-point IR.
This changes the methods in CGExprScalar to use
FixedPointBuilder to generate IR for fixed-point
conversions and operations.

Since FixedPointBuilder emits padded operations slightly
differently than the original code, some tests change.

Reviewed By: leonardchan

Differential Revision: https://reviews.llvm.org/D86282
2020-08-24 14:37:07 +02:00
Bevin Hansson 1a995a0af3 [ADT] Move FixedPoint.h from Clang to LLVM.
This patch moves FixedPointSemantics and APFixedPoint
from Clang to LLVM ADT.

This will make it easier to use the fixed-point
classes in LLVM for constructing an IR builder for
fixed-point and for reusing the APFixedPoint class
for constant evaluation purposes.

RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-August/144025.html

Reviewed By: leonardchan, rjmccall

Differential Revision: https://reviews.llvm.org/D85312
2020-08-20 10:29:45 +02:00
Bruno Ricci 473fbc90d1
[clang][NFC] Store a pointer to the ASTContext in ASTDumper and TextNodeDumper
In general there is no way to get to the ASTContext from most AST nodes
(Decls are one of the exception). This will be a problem when implementing
the rest of APValue::dump since we need the ASTContext to dump some kinds of
APValues.

The ASTContext* in ASTDumper and TextNodeDumper is not always non-null.
This is because we still want to be able to use the various dump() functions
in a debugger.

No functional changes intended.

Reverted in fcf4d5e449 since a few dump()
functions in lldb where missed.
2020-07-03 13:59:22 +01:00
Bruno Ricci fcf4d5e449
Revert "[clang][NFC] Store a pointer to the ASTContext in ASTDumper and TextNodeDumper"
This reverts commit aa7fd905e4.

I missed some dump() functions.
2020-07-02 19:40:09 +01:00
Bruno Ricci aa7fd905e4
[clang][NFC] Store a pointer to the ASTContext in ASTDumper and TextNodeDumper
In general there is no way to get to the ASTContext from most AST nodes
(Decls are one of the exception). This will be a problem when implementing
the rest of APValue::dump since we need the ASTContext to dump some kinds of
APValues.

The ASTContext* in ASTDumper and TextNodeDumper is not always
non-null. This is because we still want to be able to use the various
dump() functions in a debugger.

No functional changes intended.
2020-07-02 19:29:02 +01:00
Bevin Hansson fefa34faf5 [CodeGen] Use the common semantic for fixed-point codegen, not the result semantic.
Summary:
Using the result semantic is wrong in some cases, such as
unsigned fixed-point + signed integer. In this case, the
result semantic is unsigned and the common semantic is
signed.

Reviewers: leonardchan

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D82662
2020-06-29 16:22:29 +02:00
Melanie Blower f4aaed3bf1 Reland D81869 "Modify FPFeatures to use delta not absolute settings"
This reverts commit defd43a5b3.
with correction to solve msan report

To solve https://bugs.llvm.org/show_bug.cgi?id=46166 where the
floating point settings in PCH files aren't compatible, rewrite
FPFeatures to use a delta in the settings rather than absolute settings.
With this patch, these floating point options can be benign.

Reviewers: rjmccall

Differential Revision: https://reviews.llvm.org/D81869
2020-06-27 01:34:57 -07:00
Melanie Blower defd43a5b3 Revert "Revert "Revert "Modify FPFeatures to use delta not absolute settings"""
This reverts commit 9518763d71.
Memory sanitizer fails in CGFPOptionsRAII::CGFPOptionsRAII dtor
2020-06-26 08:47:04 -07:00
Melanie Blower 9518763d71 Revert "Revert "Modify FPFeatures to use delta not absolute settings""
This reverts commit b55d723ed6.
Reapply Modify FPFeatures to use delta not absolute settings

To solve https://bugs.llvm.org/show_bug.cgi?id=46166 where the
floating point settings in PCH files aren't compatible, rewrite
FPFeatures to use a delta in the settings rather than absolute settings.
With this patch, these floating point options can be benign.

Reviewers: rjmccall

Differential Revision: https://reviews.llvm.org/D81869
2020-06-26 08:00:08 -07:00
Melanie Blower b55d723ed6 Revert "Modify FPFeatures to use delta not absolute settings"
This reverts commit 3a748cbf86.
I'm reverting this commit because I forgot to format the commit message
propertly. Sorry for the thrash.
2020-06-26 07:52:57 -07:00
Melanie Blower 3a748cbf86 Modify FPFeatures to use delta not absolute settings 2020-06-26 07:41:09 -07:00
Tyker 51e4aa87e0 attempt to fix failing buildbots after 3bab88b7ba
Prevent IR-gen from emitting consteval declarations

Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.
2020-06-15 12:58:37 +02:00
Kirill Bobyrev 550c4562d1 Revert "Prevent IR-gen from emitting consteval declarations"
This reverts commit 3bab88b7ba.

This patch causes test failures:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-quick/builds/17260
2020-06-15 12:14:15 +02:00
Tyker 3bab88b7ba Prevent IR-gen from emitting consteval declarations
Summary: with this patch instead of emitting calls to consteval function. the IR-gen will emit a store of the already computed result.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D76420
2020-06-15 10:47:14 +02:00
Akira Hatanaka c9a52de002 [CodeGen] Simplify the way lifetime of block captures is extended
Rather than pushing inactive cleanups for the block captures at the
entry of a full expression and activating them during the creation of
the block literal, just call pushLifetimeExtendedDestroy to ensure the
cleanups are popped at the end of the scope enclosing the block
expression.

rdar://problem/63996471

Differential Revision: https://reviews.llvm.org/D81624
2020-06-11 16:06:22 -07:00
John McCall 7fac1acc61 Set the LLVM FP optimization flags conservatively.
Functions can have local pragmas that override the global settings.
We set the flags eagerly based on global settings, but if we emit
an expression under the influence of a pragma, we clear the
appropriate flags from the function.

In order to avoid doing a ton of redundant work whenever we emit
an FP expression, configure the IRBuilder to default to global
settings, and only reconfigure it when we see an FP expression
that's not using the global settings.

Patch by Michele Scandale!

https://reviews.llvm.org/D80462
2020-06-11 18:16:41 -04:00
Arthur Eubanks ce7d3e1c55 Reland (again) D80966 [codeview] Put !heapallocsite on calls to operator new
Check that getDebugInfo() is not null, as in the first revision, before
calling getDebugInfo()->addHeapAllocSiteMetadata().
Else would cause a crash with a new expression in a default arg.

---

Clang marks calls to operator new as heap allocation sites, but the
operator declared at global scope returns a void pointer. There is no
explicit cast in the code, so the compiler has to write down the
allocated type itself.

Also generalize a cast to use CallBase, so that we mark heap alloc sites
when exceptions are enabled.

Differential Revision: https://reviews.llvm.org/D80966
2020-06-09 09:27:32 -07:00
Arthur Eubanks a92ce3b706 Revert "Reland D80966 [codeview] Put !heapallocsite on calls to operator new"
This reverts commit b6e143aa54.

Causes https://bugs.chromium.org/p/chromium/issues/detail?id=1092370#c5.
Will investigate and reland (again).
2020-06-08 12:49:41 -07:00
Fangrui Song fc935fc35b Reland D80979 [clang] Implement VectorType logic not operator
With a fix to use -triple %itanium_abi_triple

Differential Revision: https://reviews.llvm.org/D80979
2020-06-08 09:32:30 -07:00
Nico Weber abca3b7b2c Revert "[clang] Implement VectorType logic not operator."
This reverts commit a0de3335ed.
Breaks check-clang on Windows, see e.g.
https://reviews.llvm.org/D80979#2078750 (but fails on all
other Windows bots too).
2020-06-08 06:45:21 -04:00
Jun Ma a0de3335ed [clang] Implement VectorType logic not operator.
Differential Revision: https://reviews.llvm.org/D80979
2020-06-08 08:41:01 +08:00
Fangrui Song b6e143aa54 Reland D80966 [codeview] Put !heapallocsite on calls to operator new
With a change to use `CGM.getCodeGenOpts().getDebugInfo() != codegenoptions::NoDebugInfo`
instead of `getDebugInfo()`,
to fix `Profile-<arch> :: instrprof-gcov-multithread_fork.test`

See CodeGenModule::CodeGenModule, `EmitGcovArcs || EmitGcovNotes` can
set `clang::CodeGen::CodeGenModule::DebugInfo`.

---

Clang marks calls to operator new as heap allocation sites, but the
operator declared at global scope returns a void pointer. There is no
explicit cast in the code, so the compiler has to write down the
allocated type itself.

Also generalize a cast to use CallBase, so that we mark heap alloc sites
when exceptions are enabled.

Differential Revision: https://reviews.llvm.org/D80966
2020-06-07 13:35:20 -07:00
Florian Hahn 4affc444b4 [Matrix] Implement * binary operator for MatrixType.
This patch implements the * binary operator for values of
MatrixType. It adds support for matrix * matrix, scalar * matrix and
matrix * scalar.

For the matrix, matrix case, the number of columns of the first operand
must match the number of rows of the second. For the scalar,matrix variants,
the element type of the matrix must match the scalar type.

Reviewers: rjmccall, anemet, Bigcheese, rsmith, martong

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D76794
2020-06-07 11:11:27 +01:00
Douglas Yung 059ba74bb6 Revert "[codeview] Put !heapallocsite on calls to operator new"
This reverts commit 672ed53860.

This commit is hitting an assertion failure across multiple bots in the test:
Profile-<arch> :: instrprof-gcov-multithread_fork.test

Failing bots include:
http://lab.llvm.org:8011/builders/llvm-avr-linux/builds/2205
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-lld/builds/8967
http://lab.llvm.org:8011/builders/clang-cmake-armv7-full/builds/10789
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/27750
http://lab.llvm.org:8011/builders/sanitizer-ppc64be-linux/builds/16751
2020-06-06 23:30:46 +00:00
Reid Kleckner 672ed53860 [codeview] Put !heapallocsite on calls to operator new
Clang marks calls to operator new as heap allocation sites, but the
operator declared at global scope returns a void pointer. There is no
explicit cast in the code, so the compiler has to write down the
allocated type itself.

Also generalize a cast to use CallBase, so that we mark heap alloc sites
when exceptions are enabled.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D80966
2020-06-05 12:52:38 -07:00
Min-Yih Hsu 4431d64c10 Support ExtVectorType conditional operator
Extension vectors now can be used in element-wise conditional selector.
For example:
```
R[i] = C[i]? A[i] : B[i]
```
This feature was previously only enabled in OpenCL C. Now it's also
available in C. Not that it has different behaviors than GNU vectors
(i.e. __vector_size__). Extension vectors selects on signdness of the
vector. GNU vectors on the other hand do normal bool conversions. Also,
this feature is not available in C++.

Differential Revision: https://reviews.llvm.org/D80574
2020-06-02 16:35:42 +00:00
John McCall 8a8d703be0 Fix how cc1 command line options are mapped into FP options.
Canonicalize on storing FP options in LangOptions instead of
redundantly in CodeGenOptions.  Incorporate -ffast-math directly
into the values of those LangOptions rather than considering it
separately when building FPOptions.  Build IR attributes from
those options rather than a mix of sources.

We should really simplify the driver/cc1 interaction here and have
the driver pass down options that cc1 directly honors.  That can
happen in a follow-up, though.

Patch by Michele Scandale!
https://reviews.llvm.org/D80315
2020-06-01 22:00:30 -04:00
Florian Hahn 8f3f88d2f5 [Matrix] Implement matrix index expressions ([][]).
This patch implements matrix index expressions
(matrix[RowIdx][ColumnIdx]).

It does so by introducing a new MatrixSubscriptExpr(Base, RowIdx, ColumnIdx).
MatrixSubscriptExprs are built in 2 steps in ActOnMatrixSubscriptExpr. First,
if the base of a subscript is of matrix type, we create a incomplete
MatrixSubscriptExpr(base, idx, nullptr). Second, if the base is an incomplete
MatrixSubscriptExpr, we create a complete
MatrixSubscriptExpr(base->getBase(), base->getRowIdx(), idx)

Similar to vector elements, it is not possible to take the address of
a MatrixSubscriptExpr.
For CodeGen, a new MatrixElt type is added to LValue, which is very
similar to VectorElt. The only difference is that we may need to cast
the type of the base from an array to a vector type when accessing it.

Reviewers: rjmccall, anemet, Bigcheese, rsmith, martong

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D76791
2020-06-01 20:08:49 +01:00
Christopher Tetreault 796898172c [SVE] Eliminate calls to default-false VectorType::get() from Clang
Reviewers: efriedma, david-arm, fpetrogalli, ddunbar, rjmccall

Reviewed By: fpetrogalli, rjmccall

Subscribers: tschuett, rkruppe, psnobl, dmgreen, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80323
2020-06-01 10:02:14 -07:00
Florian Hahn 6f6e91d193 [Matrix] Implement + and - operators for MatrixType.
This patch implements the + and - binary operators for values of
MatrixType. It adds support for matrix +/- matrix, scalar +/- matrix and
matrix +/- scalar.

For the matrix, matrix case, the types must initially be structurally
equivalent. For the scalar,matrix variants, the element type of the
matrix must match the scalar type.

Reviewers: rjmccall, anemet, Bigcheese, rsmith, martong

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D76793
2020-05-29 20:42:22 +01:00
Melanie Blower 827be690dc [clang] FastMathFlags.allowContract should be initialized only from FPFeatures.allowFPContractAcrossStatement
Summary: Fix bug introduced in D72841 adding support for pragma float_control

Reviewers: rjmccall, Anastasia

Differential Revision: https://reviews.llvm.org/D79903
2020-05-20 06:19:10 -07:00
Melanie Blower f5360d4bb3 Reapply "Add support for #pragma float_control" with buildbot fixes
Add support for #pragma float_control

Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D72841

This reverts commit fce82c0ed3.
2020-05-04 05:51:25 -07:00
Melanie Blower fce82c0ed3 Revert "Reapply "Add support for #pragma float_control" with improvements to"
This reverts commit 69aacaf699.
2020-05-01 10:31:09 -07:00
Melanie Blower 69aacaf699 Reapply "Add support for #pragma float_control" with improvements to
test cases
Add support for #pragma float_control

Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D72841

This reverts commit 85dc033cac, and makes
corrections to the test cases that failed on buildbots.
2020-05-01 10:03:30 -07:00
Melanie Blower 85dc033cac Revert "Add support for #pragma float_control"
This reverts commit 4f1e9a17e9.
due to fail on buildbot, sorry for the noise
2020-05-01 06:36:58 -07:00
Melanie Blower 4f1e9a17e9 Add support for #pragma float_control
Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D72841
2020-05-01 06:14:24 -07:00
Aaron Ballman 6a30894391 C++2a -> C++20 in some identifiers; NFC. 2020-04-21 15:37:19 -04:00
Erich Keane 5f0903e9be Reland Implement _ExtInt as an extended int type specifier.
I fixed the LLDB issue, so re-applying the patch.

This reverts commit a4b88c0449.
2020-04-17 10:45:48 -07:00
Sterling Augustine a4b88c0449 Revert "Implement _ExtInt as an extended int type specifier."
This reverts commit 61ba1481e2.

I'm reverting this because it breaks the lldb build with
incomplete switch coverage warnings. I would fix it forward,
but am not familiar enough with lldb to determine the correct
fix.

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:3958:11: error: enumeration values 'DependentExtInt' and 'ExtInt' not handled in switch [-Werror,-Wswitch]
  switch (qual_type->getTypeClass()) {
          ^
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:4633:11: error: enumeration values 'DependentExtInt' and 'ExtInt' not handled in switch [-Werror,-Wswitch]
  switch (qual_type->getTypeClass()) {
          ^
lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp:4889:11: error: enumeration values 'DependentExtInt' and 'ExtInt' not handled in switch [-Werror,-Wswitch]
  switch (qual_type->getTypeClass()) {
2020-04-17 10:29:40 -07:00
Benjamin Kramer b639091c02 Change users of CreateShuffleVector to pass the masks as int instead of Constants
No functionality change intended.
2020-04-17 16:34:29 +02:00
Erich Keane 61ba1481e2 Implement _ExtInt as an extended int type specifier.
Introduction/Motivation:
LLVM-IR supports integers of non-power-of-2 bitwidth, in the iN syntax.
Integers of non-power-of-two aren't particularly interesting or useful
on most hardware, so much so that no language in Clang has been
motivated to expose it before.

However, in the case of FPGA hardware normal integer types where the
full bitwidth isn't used, is extremely wasteful and has severe
performance/space concerns.  Because of this, Intel has introduced this
functionality in the High Level Synthesis compiler[0]
under the name "Arbitrary Precision Integer" (ap_int for short). This
has been extremely useful and effective for our users, permitting them
to optimize their storage and operation space on an architecture where
both can be extremely expensive.

We are proposing upstreaming a more palatable version of this to the
community, in the form of this proposal and accompanying patch.  We are
proposing the syntax _ExtInt(N).  We intend to propose this to the WG14
committee[1], and the underscore-capital seems like the active direction
for a WG14 paper's acceptance.  An alternative that Richard Smith
suggested on the initial review was __int(N), however we believe that
is much less acceptable by WG14.  We considered _Int, however _Int is
used as an identifier in libstdc++ and there is no good way to fall
back to an identifier (since _Int(5) is indistinguishable from an
unnamed initializer of a template type named _Int).

[0]https://www.intel.com/content/www/us/en/software/programmable/quartus-prime/hls-compiler.html)
[1]http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2472.pdf

Differential Revision: https://reviews.llvm.org/D73967
2020-04-17 07:10:57 -07:00
Benjamin Kramer 3ee1ec0b9d LangOptions cannot depend on ASTContext, make it not use ASTContext directly
Fixes a layering violation introduced in 2ba4e3a459.
2020-04-16 11:46:35 +02:00
Melanie Blower 2ba4e3a459 Move BinaryOperators.FPOptions to trailing storage
Reviewers: rjmccall

Differential Revision: https://reviews.llvm.org/D76384
2020-04-15 12:57:31 -07:00
Benjamin Kramer 6f64daca8f Upgrade calls to CreateShuffleVector to use the preferred form of passing an array of ints
No functionality change intended.
2020-04-15 12:51:38 +02:00