SROA has 3 data-structures where it stores sets of instructions that should
be deleted:
- DeadUsers -> instructions that are UB or have no users
- DeadOperands -> instructions that are UB or operands of useless phis
- DeadInsts -> "dead" instructions, including loads of uninitialized memory
with users
The first 2 sets can be RAUW with poison instead of undef. No brainer as UB
can be replaced with poison, and for instructions with no users RAUW is a
NOP.
The 3rd case cannot be currently replaced with poison because the set mixes
the loads of uninit memory. I leave that alone for now.
Another case where we can use poison is in the construction of vectors from
multiple loads. The base vector for the first insertelement is now poison as
it doesn't matter as it is fully overwritten by inserts.
Differential Revision: https://reviews.llvm.org/D116887
This implements the clang side of D116531. The elementtype
attribute is added for all indirect constraints (*) and tests are
updated accordingly.
Differential Revision: https://reviews.llvm.org/D116666
This reverts commit 640beb38e7.
That commit caused performance degradtion in Quicksilver test QS:sGPU and a functional test failure in (rocPRIM rocprim.device_segmented_radix_sort).
Reverting until we have a better solution to s_cselect_b64 codegen cleanup
Change-Id: Ibf8e397df94001f248fba609f072088a46abae08
Reviewed By: kzhuravl
Differential Revision: https://reviews.llvm.org/D115960
Change-Id: Id169459ce4dfffa857d5645a0af50b0063ce1105
stdcall name mangling requires a suffix with the number equal to the sum of the byte count of all parameter types. In the case of a function prototype that has a parameter type of an incomplete type it is impossible to get the size of the type. While such a function is not callable or able to be defined in the TU, it may still be mangled when generating debug info, which would previously lead to a crash.
This patch fixes that by simply bailing out of the loop and using the so far accumulated byte count. This matches GCCs behaviour as well: bc8d6c6013/gcc/config/i386/winnt.c (L203)
Fixes https://github.com/llvm/llvm-project/issues/52782
Differential Revision: https://reviews.llvm.org/D116020
In particular, this also preserves undef when loading from padding,
rather than converting it to zero through a different codepath.
This is the remaining part of D115924.
This builds on the code from D114963, and extends it to handle calls both direct and indirect. With the revised code structure (from series of previously landed NFCs), this is pretty straight forward.
One thing to note is that we can not infer writeonly for arguments which might be captured. If the pointer can be read back by the caller, and then read through, we have no way to track that. This is the same restriction we have for readonly, except that we get no mileage out of the "callee can be readonly" exception since a writeonly param on a readonly function is either a) readnone or b) UB. This means we can't actually infer much unless nocapture has already been inferred.
Differential Revision: https://reviews.llvm.org/D115003
The fold for merging a GEP of GEP into a single GEP currently bails
if doing so would result in notional overindexing. The justification
given in the comment above this check is dangerously incorrect: GEPs
with notional overindexing are perfectly fine, and if some code
treats them incorrectly, then that code is broken, not the GEP.
Such a GEP might legally appear in source IR, so only preventing
its creation cannot be sufficient. (The constant folder also ends
up canonicalizing the GEP to remove the notional overindexing, but
that's neither here nor there.)
This check dates back to
bd4fef4a89,
and as far as I can tell the original issue this was trying to
patch around has since been resolved.
Differential Revision: https://reviews.llvm.org/D116587
The run line of stack-protector-guard.c doesn't specify the triple,
which means it depends on the platform running the test. This makes
some failure hidden.
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D116003
This reverts commit a954558e87.
Thanks Yuanfang's help. I think I found the root cause of the buildbot
fail.
The failed test has both Memory and Immediate X86Operand. All data of
different operand kinds share the same memory space by a union
definition. So it has chance we get the wrong result if we don't check
the operand kind.
It's probably it happen to be the correct value in my local environment
so that I can't reproduce the fail.
Differential Revision: https://reviews.llvm.org/D116090
D115225 tried to roll back the effects on symbols of MS inline asm
introduced by D113096. But the combination of the conditions cannot
match all the changes. As a result, there are still fails after the
patch.
This patch fixes the problem by checking the exact conditions for MS
global variables, i.e., variable (by FrontendSize != 0) + non rip/eip
(by DefaultBaseReg == 0), so that we can fully roll back for D113096.
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D116090
HVX does not have load/store instructions for vector predicates (i.e. bool
vectors). Because of that, vector predicates need to be converted to another
type before being stored, and the most convenient representation is an HVX
vector.
As a consequence, in C/C++, source-level builtins that either take or
produce vector predicates take or return regular vectors instead. On the
other hand, the corresponding LLVM intrinsics do have boolean types that,
and so a conversion of the operand or the return value was necessary.
This conversion would happen inside clang's codegen, but was somewhat
fragile.
This patch changes the strategy: a builtin that takes a vector predicate
now really expects a vector predicate. Since such a predicate cannot be
provided via a variable, this builtin must be composed with other builtins
that either convert vector to a predicate (V6_vandvrt) or predicate to a
vector (V6_vandqrt).
For users using builtins defined in hvx_hexagon_protos.h there is no impact:
the conversions were added to that file. Other users will need to insert
- __builtin_HEXAGON_V6_vandvrt[_128B](V, -1) to convert vector V to a
vector predicate, or
- __builtin_HEXAGON_V6_vandqrt[_128B](Q, -1) to convert vector predicate Q
to a vector.
Builtins __builtin_HEXAGON_V6_vmaskedstore.* are a temporary exception to
that, but they are deprecated and should not be used anyway. In the future
they will either follow the same rule, or be removed.
This patch implements __builtin_reduce_xor as specified in D111529.
Reviewed By: fhahn, aaron.ballman
Differential Revision: https://reviews.llvm.org/D115231
Control-Flow Integrity (CFI) replaces references to address-taken
functions with pointers to the CFI jump table. This is a problem
for low-level code, such as operating system kernels, which may
need the address of an actual function body without the jump table
indirection.
This change adds the __builtin_function_start() builtin, which
accepts an argument that can be constant-evaluated to a function,
and returns the address of the function body.
Link: https://github.com/ClangBuiltLinux/linux/issues/1353
Depends on D108478
Reviewed By: pcc, rjmccall
Differential Revision: https://reviews.llvm.org/D108479
The UpperBound of RVV type in debug info should be elements count minus one,
as the LowerBound start from zero.
Reviewed By: HsiangKai
Differential Revision: https://reviews.llvm.org/D115430
This is the last cleanup step resulting from D115804 .
Now that clang uses intrinsics when we're in the special FP mode,
we don't need a function attribute as an indicator to the backend.
The LLVM part of the change is in D115885.
Differential Revision: https://reviews.llvm.org/D115886
This reverts commit 9fd4f80e33.
This breaks SingleSource/Regression/C/gcc-c-torture/execute/pr19687.c
in test-suite. Either the test is incorrect, or clang is generating
incorrect union initialization code. I've submitted
https://reviews.llvm.org/D115994 to fix the test, assuming my
interpretation is correct. Reverting this in the meantime as it
may take some time to resolve.
We were being wildly inconsistent about what memory access was implied by an indirect function call. Depending on the call site attributes, you could get anything from a read, to unknown, to none at all. (The last was a miscompile.)
We were also always traversing the uses of a readonly indirect call. This is entirely unneeded as the indirect call does not capture. The callee might capture itself internally, but that has no implications for this caller. (See the nice explanation in the CaptureTracking comments if that case is confusing.)
Note that elsewhere in the same file, we were correctly computing the nocapture attribute for indirect calls. The changed case only resulted in conservatism when computing memory attributes if say the return value was written to.
Differential Revision: https://reviews.llvm.org/D115916
There are a number of places that specially handle loads from a
uniform value where all the bits are the same (zero, one, undef,
poison), because we a) don't care about the load offset in that
case and b) it bypasses casts that might not be legal generally
but do work with uniform values.
We had multiple implementations of this, with a different set of
supported values each time, as well as incomplete type checks in
some cases. In particular, this fixes the assertion reported in
https://reviews.llvm.org/D114889#3198921, as well as a similar
assertion that could be triggered via constant folding.
Differential Revision: https://reviews.llvm.org/D115924
This supports bitcode compilation using `clang -fwasm-exceptions`.
---
The current situation:
Currently the backend requires two options for Wasm EH:
`-wasm-enable-eh` and `-exception-model=wasm`. Wasm SjLj requires two
options as well: `-wasm-enable-sjlj` and `-exception-model=wasm`. When
using Wasm EH via Emscripten, you only need to pass `-fwasm-exceptions`,
and these options will be added within the clang driver. This
description will focus on the case of Wasm EH going forward, but Wasm
SjLj's case is similar.
When you pass `-fwasm-exceptions` to emcc and clang driver, the clang
driver adds these options to the command line that calls the clang
frontend (`clang -cc1`): `-mllvm -wasm-enable-eh` and
`-exception-model=wasm`. `-wasm-enable-eh` is prefixed with `-mllvm`, so
it is passed as is to the backend. But `-exception-model` is parsed and
processed within the clang frontend and stored in `LangOptions` class.
This info is later transferred to `TargetOptions` class, and then
eventually passed to `MCAsmInfo` class. All LLVM code queries this
`MCAsmInfo` to get the exception model.
---
Problem:
The problem is the whole `LangOptions` processing is bypassed when
compiling bitcode, so the information transfer of `LangOptions` ->
`TargetOptions` -> `MCAsmInfo` does not happen. They are all set to
`ExceptionHandling::None`, which is the default value.
---
What other targets do, and why we can't do the same:
Other targets support bitcode compilation by the clang driver, but they
can do that by using different triples. For example, X86 target supports
multiple triples, each of which has its own subclass of `MCAsmInfo`, so
it can hardcode the appropriate exception model within those subclasses'
constructors. But we don't have separate triples for each exception
mode: none, emscripten, and wasm.
---
What this CL does:
If we can figure out whether `-wasm-enable-eh` is passed to the backend,
we can programatically set the exception model from the backend, rather
than requiring it to be passed.
So we check `WasmEnableEH` and `WasmEnableSjLj` variables, which are
`cl::opt` for `-wasm-enable-eh` and `-wasm-enable-sjlj`, in
`WebAssemblyMCAsmInfo` constructor, and if either of them is set, we set
`MCAsmInfo.ExceptionType` to Wasm. `TargetOptions` cannot be updated
there, so we make sure they are the same later.
Fixes https://github.com/emscripten-core/emscripten/issues/15712.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D115893
We got an unintended consequence of the optimizer getting smarter when
compiling in a non-standard mode, and there's no good way to inhibit
those optimizations at a later stage. The test is based on an example
linked from D92270.
We allow the "no-strict-float-cast-overflow" exception to normal C
cast rules to preserve legacy code that does not expect overflowing
casts from FP to int to produce UB. See D46236 for details.
Differential Revision: https://reviews.llvm.org/D115804
In 32bit mode, attaching TBAA metadata to the store following the call
to inline assembler results in describing the wrong type by making a
fake lvalue(i.e., whatever the inline assembler happens to leave in
EAX:EDX.) Even if inline assembler somehow describes the correct type,
setting TBAA information on return type of call to inline assembler is
likely not correct, since TBAA rules need not apply to inline assembler.
Differential Revision: https://reviews.llvm.org/D115320
~(iN X s>> (N-1)) & Y --> (X s< 0) ? 0 : Y
https://alive2.llvm.org/ce/z/JKlQ9x
This is similar to D111410 / 727e642e97 ,
but it includes a 'not' of the signbit and so it
saves an instruction in the basic pattern.
DAGCombiner or target-specific folds can expand
this back into bit-hacks.
The diffs in the logical-select tests are not true
regressions - running early-cse and another round
of instcombine is expected in a normal opt pipeline,
and that reduces back to a minimal form as shown
in the duplicated PhaseOrdering test.
I have no understanding of the SystemZ diffs, so
I made the minimal edits suggested by FileCheck to
make that test pass again. That whole test file is
wrong though. It is running the entire optimizer (-O2)
to check IR, and then topping that by even running
codegen and checking asm. It needs to be split up.
Fixes#52631
The basic idea to this is that a) having a single canonical type makes CSE easier, and b) many of our transforms are inconsistent about which types we end up with based on visit order.
I'm restricting this to constants as for non-constants, we'd have to decide whether the simplicity was worth extra instructions. For constants, there are no extra instructions.
We chose the canonical type as i64 arbitrarily. We might consider changing this to something else in the future if we have cause.
Differential Revision: https://reviews.llvm.org/D115387
This reverts commit 2b554920f1.
This change causes tsan test timeout on x86_64-linux-autoconf.
The timeout can be reproduced by:
git clone https://github.com/llvm/llvm-zorg.git
BUILDBOT_CLOBBER= BUILDBOT_REVISION=eef8f3f85679c5b1ae725bade1c23ab7bb6b924f llvm-zorg/zorg/buildbot/builders/sanitizers/buildbot_standard.sh
Every generated IR has a corresponding target-abi value, so
encoding a non-empty value would improve the robustness and
correctness.
Reviewed By: asb, jrtc27, arichardson
Differential Revision: https://reviews.llvm.org/D105555
Originially there are two places that does parsing - `parseArchString` and
`parseFeatures`, each with its code on dependency check and implication.
This patch extracts common parts of the two as functions of `RISCVISAInfo`
and let them 2 use it.
Reviewed By: asb
Differential Revision: https://reviews.llvm.org/D112359
D113096 solved the "undefined reference to xxx" issue by adding
constraint *m for the global var. But it has strong side effect due to
the symbol in the assembly being replaced with constraint variable.
This leads to some lowering fails. https://godbolt.org/z/h3nWoerPe
This patch fix the problem by use the constraint *m as place holder
rather than real constraint. It has negligible effect for the existing
code generation.
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D115225
The default for min is changed to 1. The behaviour of -mvscale-{min,max}
in Clang is also changed such that 16 is the max vscale when targeting
SVE and no max is specified.
Reviewed By: sdesmalen, paulwalker-arm
Differential Revision: https://reviews.llvm.org/D113294
WG14 adopted the _ExtInt feature from Clang for C23, but renamed the
type to be _BitInt. This patch does the vast majority of the work to
rename _ExtInt to _BitInt, which accounts for most of its size. The new
type is exposed in older C modes and all C++ modes as a conforming
extension. However, there are functional changes worth calling out:
* Deprecates _ExtInt with a fix-it to help users migrate to _BitInt.
* Updates the mangling for the type.
* Updates the documentation and adds a release note to warn users what
is going on.
* Adds new diagnostics for use of _BitInt to call out when it's used as
a Clang extension or as a pre-C23 compatibility concern.
* Adds new tests for the new diagnostic behaviors.
I want to call out the ABI break specifically. We do not believe that
this break will cause a significant imposition for early adopters of
the feature, and so this is being done as a full break. If it turns out
there are critical uses where recompilation is not an option for some
reason, we can consider using ABI tags to ease the transition.
When targeting FreeBSD on a Linux host with a copy
of system libc++, Clang prepends /usr/include/c++/v1
to the search paths even with -ffreestanding, and
fails to compile a program with a
single #include <xmmintrin.h>
Dropping the path with -nostdlibinc.
Differential Revision: https://reviews.llvm.org/D114497
Swap AIC and IC neighbouring in pipeline. This looks more natural and even
almost has no effect for now (three slightly touched tests of test-suite). Also
this could be the first step towards merging AIC (or its part) to -O2 pipeline.
After several changes in AIC (like D108091, D108201, D107766, D109515, D109236)
there've been observed several regressions (like PR52078, PR52253, PR52289)
that were fixed in different passes (see D111330, D112721) by extending their
functionality, but these regressions were exposed since changed AIC prevents IC
from making some of early optimizations.
This is common problem and it should be fixed by just moving AIC after IC
which looks more logically by itself: make aggressive instruction combining
only after failed ordinary one.
Fixes PR52289
Reviewed By: spatel, RKSimon
Differential Revision: https://reviews.llvm.org/D113179
This fixes a bug in 740057d. There's two ways to describe the issue:
* One caller hasn't yet proven nocapture on the argument. Given that, the inference routine is responsible for bailing out on a potential capture.
* Even if we know the argument is nocapture, the access inference needs to traverse the exact set of users the capture tracking would (or exit conservatively). Even if capture tracking can prove a store is non-capturing (e.g. to a local alloc which doesn't escape), we still need to track the copy of the pointer to see if it's later reloaded and accessed again.
Note that all the test changes except the newly added ones appear to be false negatives. That is, cases where we could prove writeonly, but the current code isn't strong enough. That's why I didn't spot this originally.
This adjusts all the MVE and CDE intrinsics now that v2i1 is a legal
type, to use a <2 x i1> as opposed to emulating the predicate with a
<4 x i1>. The v4i1 workarounds have been removed leaving the natural
v2i1 types, notably in vctp64 which now generates a v2i1 type.
AutoUpgrade code has been added to upgrade old IR, which needs to
convert the old v4i1 to a v2i1 be converting it back and forth to an
integer with arm.mve.v2i and arm.mve.i2v intrinsics. These should be
optimized away in the final assembly.
Differential Revision: https://reviews.llvm.org/D114455
Alex Xu (Hello71)