Generate nuw GEPs for struct member accesses, as inbounds + non-negative
implies nuw.
Regression tests are updated using update scripts where possible, and by
find + replace where not.
In the beginning, Clang only emitted atomic IR for operations it knew
the
underlying microarch had instructions for, meaning it required
significant
knowledge of the target. Later, the backend acquired the ability to
lower
IR to libcalls. To avoid duplicating logic and improve logic locality,
we'd like to move as much as possible to the backend.
There are many ways to describe this change. For example, this change
reduces the variables Clang uses to decide whether to emit libcalls or
IR, down to only the atomic's size.
Set the writable and dead_on_unwind attributes for sret arguments. These
indicate that the argument points to writable memory (and it's legal to
introduce spurious writes to it on entry to the function) and that the
argument memory will not be used if the call unwinds.
This enables additional MemCpyOpt/DSE/LICM optimizations.
This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.
The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.
Differential Revision: https://reviews.llvm.org/D123115
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
This reverts commit aacfbb953eb705af2ecfeb95a6262818fa85dd92.
Revert "Fix lit test failures in CodeGenCoroutines"
This reverts commit 63fff0f5bffe20fa2c84a45a41161afa0043cb34.
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)
This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:
(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.
(2) The remaining tests are updated manually.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108453
Resolve lit failures in clang after 8ca4b3e's land
Fix lit test failures in clang-ppc* and clang-x64-windows-msvc
Fix missing failures in clang-ppc64be* and retry fixing clang-x64-windows-msvc
Fix internal_clone(aarch64) inline assembly
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
This reverts the following commits:
37ca7a795b277c20c02a218bf44052278c03344b
9aa6c72b92b6c89cc6d23b693257df9af7de2d15
705387c5074bcca36d626882462ebbc2bcc3bed4
8ca4b3ef19fe82d7ad6a6e1515317dcc01b41515
80dba72a669b5416e97a42fd2c2a7bc5a6d3f44a
This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:
(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.
(2) The remaining tests are updated manually.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108453
The ability to specify alignment was recently added, and it's an
important property which we should ensure is set as expected by
Clang. (Especially before making further changes to Clang's code in
this area.) But, because it's on the end of the lines, the existing
tests all ignore it.
Therefore, update all the tests to also verify the expected alignment
for atomicrmw and cmpxchg. While I was in there, I also updated uses
of 'load atomic' and 'store atomic', and added the memory ordering,
where that was missing.
For a default visibility external linkage definition, dso_local is set for ELF
-fno-pic/-fpie and COFF and Mach-O. Since default clang -cc1 for ELF is similar
to -fpic ("PIC Level" is not set), this nuance causes unneeded binary format differences.
To make emitted IR similar, ELF -cc1 -fpic will default to -fno-semantic-interposition,
which sets dso_local for default visibility external linkage definitions.
To make this flip smooth and enable future (dso_local as definition default),
this patch replaces (function) `define ` with `define{{.*}} `,
(variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} `.
This reverts commit eb9f7c28e5fe6d75fed3587023e17f2997c8024b.
Previously this was incorrectly handling linking of the contained
type, so this merges the fixes from D88973.
This reverts commit 55c4ff91bd820d72014f63dcf7f3d5a0d3397986.
Issues were introduced as discussed in https://reviews.llvm.org/D88241
where this change made previous bugs in the linker and BitCodeWriter
visible.
Make the corresponding change that was made for byval in
b7141207a483d39b99c2b4da4eb3bb591eca9e1a. Like byval, this requires a
bulk update of the test IR tests to include the type before this can
be mandatory.
After a first attempt to fix the test-suite failures, my first recommit
caused the same failures again. I had updated CMakeList.txt files of
tests that needed -fcommon, but it turns out that there are also
Makefiles which are used by some bots, so I've updated these Makefiles
now too.
See the original commit message for more details on this change:
0a9fc9233e172601e26381810d093e02ef410f65
This includes fixes for:
- test-suite: some benchmarks need to be compiled with -fcommon, see D75557.
- compiler-rt: one test needed -fcommon, and another a change, see D75520.
This reverts commit 0a9fc9233e172601e26381810d093e02ef410f65.
Going to look at the asan failures.
I find the failures in the test suite weird, because they look
like compile time test and I don't understand how that can be
failing, but will have a brief look at that too.
This makes -fno-common the default for all targets because this has performance
and code-size benefits and is more language conforming for C code.
Additionally, GCC10 also defaults to -fno-common and so we get consistent
behaviour with GCC.
With this change, C code that uses tentative definitions as definitions of a
variable in multiple translation units will trigger multiple-definition linker
errors. Generally, this occurs when the use of the extern keyword is neglected
in the declaration of a variable in a header file. In some cases, no specific
translation unit provides a definition of the variable. The previous behavior
can be restored by specifying -fcommon.
As GCC has switched already, we benefit from applications already being ported
and existing documentation how to do this. For example:
- https://gcc.gnu.org/gcc-10/porting_to.html
- https://wiki.gentoo.org/wiki/Gcc_10_porting_notes/fno_common
Differential revision: https://reviews.llvm.org/D75056
Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to specify -fsemantic-interposition to get semantic
interposition behavior.
Semantic interposition is currently a best-effort feature. There may
still be some cases where it is not handled well.
Reviewers: peter.smith, rnk, serge-sans-paille, sfertile, jfb, jdoerfert
Subscribers: dschuff, jyknight, dylanmckay, nemanjai, jvesely, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, arphaman, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D73865
Summary:
An _Atomic of an empty struct is pretty silly. In general we just widen empty
structs to hold a byte's worth of storage, and we represent size and alignment
as 0 internally and let LLVM figure out what to do. For _Atomic it's a bit
different: the memory model mandates concrete effects occur when atomic
operations occur, so in most cases actual instructions need to get emitted. It's
really not worth trying to optimize empty struct atomics by figuring out e.g.
that a fence would do, even though sane compilers should do optimize atomics.
Further, wg21.link/p0528 will fix C++20 atomics with padding bits so that
cmpxchg on them works, which means that we'll likely need to do the zero-init
song and dance for empty atomic structs anyways (and I think we shouldn't
special-case this behavior to C++20 because prior standards are just broken).
This patch therefore makes a minor change to r176658 "Promote atomic type sizes
up to a power of two": if the width of the atomic's value type is 0, just use 1
byte for width and leave alignment as-is (since it should never be zero, and
over-aligned zero-width structs are weird but fine).
This fixes an assertion:
(NumBits >= MIN_INT_BITS && "bitwidth too small"), function get, file ../lib/IR/Type.cpp, line 241.
It seems like this has run into other assertions before (namely the unreachable
Kind check in ImpCastExprToType), but I haven't reproduced that issue with
tip-of-tree.
<rdar://problem/39678063>
Reviewers: arphaman, rjmccall
Subscribers: aheejin, cfe-commits
Differential Revision: https://reviews.llvm.org/D46613
llvm-svn: 331845
Summary:
This change is step three in the series of changes to remove alignment argument from
memcpy/memmove/memset in favour of alignment attributes. Steps:
Step 1) Remove alignment parameter and create alignment parameter attributes for
memcpy/memmove/memset. ( rL322965, rC322964, rL322963 )
Step 2) Expand the IRBuilder API to allow creation of memcpy/memmove with differing
source and dest alignments. ( rL323597 )
Step 3) Update Clang to use the new IRBuilder API.
Step 4) Update Polly to use the new IRBuilder API.
Step 5) Update LLVM passes that create memcpy/memmove calls to use the new IRBuilder API,
and those that use use MemIntrinsicInst::[get|set]Alignment() to use getDestAlignment()
and getSourceAlignment() instead.
Step 6) Remove the single-alignment IRBuilder API for memcpy/memmove, and the
MemIntrinsicInst::[get|set]Alignment() methods.
Reference
http://lists.llvm.org/pipermail/llvm-dev/2015-August/089384.htmlhttp://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html
Reviewers: rjmccall
Subscribers: jyknight, nemanjai, nhaehnle, javed.absar, sbc100, aheejin, kbarton, fedor.sergeev, cfe-commits
Differential Revision: https://reviews.llvm.org/D41677
llvm-svn: 323617
Summary:
Upstream LLVM is changing the the prototypes of the @llvm.memcpy/memmove/memset
intrinsics. This change updates the Clang tests for this change.
The @llvm.memcpy/memmove/memset intrinsics currently have an explicit argument
which is required to be a constant integer. It represents the alignment of the
dest (and source), and so must be the minimum of the actual alignment of the
two.
This change removes the alignment argument in favour of placing the alignment
attribute on the source and destination pointers of the memory intrinsic call.
For example, code which used to read:
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 100, i32 4, i1 false)
will now read
call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %dest, i8* align 4 %src, i32 100, i1 false)
At this time the source and destination alignments must be the same (Step 1).
Step 2 of the change, to be landed shortly, will relax that contraint and allow
the source and destination to have different alignments.
llvm-svn: 322964
This is a follow on from a similar LLVM commit: r253511.
Note, this was reviewed (and more details are in) http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20151109/312083.html
These intrinsics currently have an explicit alignment argument which is
required to be a constant integer. It represents the alignment of the
source and dest, and so must be the minimum of those.
This change allows source and dest to each have their own alignments
by using the alignment attribute on their arguments. The alignment
argument itself is removed.
The only code change to clang is hidden in CGBuilder.h which now passes
both dest and source alignment to IRBuilder, instead of taking the minimum of
dest and source alignments.
Reviewed by Hal Finkel.
llvm-svn: 253512
When a struct's size is not a power of 2, the corresponding _Atomic() type is
promoted to the nearest. We already correctly handled normal C++ expressions of
this form, but direct calls to the __c11_atomic_whatever builtins ended up
performing dodgy operations on the smaller non-atomic types (e.g. memcpy too
much). Later optimisations removed this as undefined behaviour.
This patch converts EmitAtomicExpr to allocate its temporaries at the full
atomic width, sidestepping the issue.
llvm-svn: 252507
Introduce an Address type to bundle a pointer value with an
alignment. Introduce APIs on CGBuilderTy to work with Address
values. Change core APIs on CGF/CGM to traffic in Address where
appropriate. Require alignments to be non-zero. Update a ton
of code to compute and propagate alignment information.
As part of this, I've promoted CGBuiltin's EmitPointerWithAlignment
helper function to CGF and made use of it in a number of places in
the expression emitter.
The end result is that we should now be significantly more correct
when performing operations on objects that are locally known to
be under-aligned. Since alignment is not reliably tracked in the
type system, there are inherent limits to this, but at least we
are no longer confused by standard operations like derived-to-base
conversions and array-to-pointer decay. I've also fixed a large
number of bugs where we were applying the complete-object alignment
to a pointer instead of the non-virtual alignment, although most of
these were hidden by the very conservative approach we took with
member alignment.
Also, because IRGen now reliably asserts on zero alignments, we
should no longer be subject to an absurd but frustrating recurring
bug where an incomplete type would report a zero alignment and then
we'd naively do a alignmentAtOffset on it and emit code using an
alignment equal to the largest power-of-two factor of the offset.
We should also now be emitting much more aggressive alignment
attributes in the presence of over-alignment. In particular,
field access now uses alignmentAtOffset instead of min.
Several times in this patch, I had to change the existing
code-generation pattern in order to more effectively use
the Address APIs. For the most part, this seems to be a strict
improvement, like doing pointer arithmetic with GEPs instead of
ptrtoint. That said, I've tried very hard to not change semantics,
but it is likely that I've failed in a few places, for which I
apologize.
ABIArgInfo now always carries the assumed alignment of indirect and
indirect byval arguments. In order to cut down on what was already
a dauntingly large patch, I changed the code to never set align
attributes in the IR on non-byval indirect arguments. That is,
we still generate code which assumes that indirect arguments have
the given alignment, but we don't express this information to the
backend except where it's semantically required (i.e. on byvals).
This is likely a minor regression for those targets that did provide
this information, but it'll be trivial to add it back in a later
patch.
I partially punted on applying this work to CGBuiltin. Please
do not add more uses of the CreateDefaultAligned{Load,Store}
APIs; they will be going away eventually.
llvm-svn: 246985
We failed to see that we should have deferred the creation of a type
which references a type currently under construction because of atomic
sugar.
This fixes PR23985.
llvm-svn: 240989
Currently clang fires assertions on x86-64 on any atomic operations for long double operands. Patch fixes codegen for such operations.
Differential Revision: http://reviews.llvm.org/D6499
llvm-svn: 224230
or a class derived from T. We already supported this when initializing
_Atomic(T) from T for most (and maybe all) other reasonable values of T.
llvm-svn: 214390
Just like on Linux, FreeBSD/armv6 assumes the system supports
ldrex/strex unconditionally. It is also used by the kernel. We can
therefore enable support for it, like we do on Linux.
While there, change one of the unit tests to explicitly test against
armv5 instead of armv7, as it actually tests whether libcalls are
emitted.
llvm-svn: 184040
- Generate atomicrmw operations in most of the cases when it's sensible to do
so.
- Don't crash in several common cases (and hopefully don't crash in more of
them).
- Add some better tests.
We now generate significantly better code for things like:
_Atomic(int) x;
...
x++;
On MIPS, this now generates a 4-instruction ll/sc loop, where previously it
generated about 30 instructions in two nested loops. On x86-64, we generate a
single lock incl, instead of a lock cmpxchgl loop (one instruction instead of
ten).
llvm-svn: 176420
