Summary:
Targets often have instructions that can sign-extend certain cases faster
than the equivalent shift-left/arithmetic-shift-right. Such cases can be
identified by matching a shift-left/shift-right pair but there are some
issues with this in the context of combines. For example, suppose you can
sign-extend 8-bit up to 32-bit with a target extend instruction.
%1:_(s32) = G_SHL %0:_(s32), i32 24 # (I've inlined the G_CONSTANT for brevity)
%2:_(s32) = G_ASHR %1:_(s32), i32 24
%3:_(s32) = G_ASHR %2:_(s32), i32 1
would reasonably combine to:
%1:_(s32) = G_SHL %0:_(s32), i32 24
%2:_(s32) = G_ASHR %1:_(s32), i32 25
which no longer matches the special case. If your shifts and extend are
equal cost, this would break even as a pair of shifts but if your shift is
more expensive than the extend then it's cheaper as:
%2:_(s32) = G_SEXT_INREG %0:_(s32), i32 8
%3:_(s32) = G_ASHR %2:_(s32), i32 1
It's possible to match the shift-pair in ISel and emit an extend and ashr.
However, this is far from the only way to break this shift pair and make
it hard to match the extends. Another example is that with the right
known-zeros, this:
%1:_(s32) = G_SHL %0:_(s32), i32 24
%2:_(s32) = G_ASHR %1:_(s32), i32 24
%3:_(s32) = G_MUL %2:_(s32), i32 2
can become:
%1:_(s32) = G_SHL %0:_(s32), i32 24
%2:_(s32) = G_ASHR %1:_(s32), i32 23
All upstream targets have been configured to lower it to the current
G_SHL,G_ASHR pair but will likely want to make it legal in some cases to
handle their faster cases.
To follow-up: Provide a way to legalize based on the constant. At the
moment, I'm thinking that the best way to achieve this is to provide the
MI in LegalityQuery but that opens the door to breaking core principles
of the legalizer (legality is not context sensitive). That said, it's
worth noting that looking at other instructions and acting on that
information doesn't violate this principle in itself. It's only a
violation if, at the end of legalization, a pass that checks legality
without being able to see the context would say an instruction might not be
legal. That's a fairly subtle distinction so to give a concrete example,
saying %2 in:
%1 = G_CONSTANT 16
%2 = G_SEXT_INREG %0, %1
is legal is in violation of that principle if the legality of %2 depends
on %1 being constant and/or being 16. However, legalizing to either:
%2 = G_SEXT_INREG %0, 16
or:
%1 = G_CONSTANT 16
%2:_(s32) = G_SHL %0, %1
%3:_(s32) = G_ASHR %2, %1
depending on whether %1 is constant and 16 does not violate that principle
since both outputs are genuinely legal.
Reviewers: bogner, aditya_nandakumar, volkan, aemerson, paquette, arsenm
Subscribers: sdardis, jvesely, wdng, nhaehnle, rovka, kristof.beyls, javed.absar, hiraditya, jrtc27, atanasyan, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61289
llvm-svn: 368487
Without this patch computeConstantDifference returns None for cases like
these:
computeConstantDifference(%x, %x)
computeConstantDifference({%x,+,16}, {%x,+,16})
Differential Revision: https://reviews.llvm.org/D65474
llvm-svn: 368193
Some of these names were abbreviated, some were not, some pluralised,
some not. Made the API difficult to use - since it's an exact 1:1
mapping to the DWARF sections - use those names (changing underscore
separation for camel casing).
llvm-svn: 368189
https://reviews.llvm.org/D65698
This adds a KnownBits analysis pass for GISel. This was done as a
pass (compared to static functions) so that we can add other features
such as caching queries(within a pass and across passes) in the future.
This patch only adds the basic pass boiler plate, and implements a lazy
non caching knownbits implementation (ported from SelectionDAG). I've
also hooked up the AArch64PreLegalizerCombiner pass to use this - there
should be no compile time regression as the analysis is lazy.
llvm-svn: 368065
This fixes a bug for making path with a //net style root absolute. I
discovered the bug while writing a test case for the VFS, which uses
these paths because they're both legal absolute paths on Windows and
Unix.
Differential revision: https://reviews.llvm.org/D65675
llvm-svn: 368053
To support spilling/filling of scalable vectors we need a more generic
representation of a stack offset than simply 'int'.
For this we introduce the StackOffset struct, which comprises multiple
offsets sized by their respective MVTs. Byte-offsets will thus be a simple
tuple such as { offset, MVT::i8 }. Adding two byte-offsets will result in a
byte offset { offsetA + offsetB, MVT::i8 }. When two offsets have different
types, we can canonicalise them to use the same MVT, as long as their
runtime sizes are guaranteed to have the same size-ratio as they would have
at compile-time.
When we have both scalable- and fixed-size objects on the stack, we can
create an offset that is:
({ offset_fixed, MVT::i8 } + { offset_scalable, MVT::nxv1i8 })
The struct also contains a getForFrameOffset() method that is specific to
AArch64 and decomposes the frame-offset to be used directly in instructions
that operate on the stack or index into the stack.
Note: This patch adds StackOffset as an AArch64-only concept, but we would
like to make this a generic concept/struct that is supported by all
interfaces that take or return stack offsets (currently as 'int'). Since
that would be a bigger change that is currently pending on D32530 landing,
we thought it makes sense to first show/prove the concept in the AArch64
target before proposing to roll this out further.
Reviewers: thegameg, rovka, t.p.northover, efriedma, greened
Reviewed By: rovka, greened
Differential Revision: https://reviews.llvm.org/D61435
llvm-svn: 368024
This updates all libraries and tools in LLVM Core to use 64-bit offsets
which directly or indirectly come to DataExtractor.
Differential Revision: https://reviews.llvm.org/D65638
llvm-svn: 368014
Using 64-bit offsets is required to fully implement 64-bit DWARF.
As these classes are used in many different libraries they should
temporarily support both 32- and 64-bit offsets.
Differential Revision: https://reviews.llvm.org/D64006
llvm-svn: 368013
Adds a two way mapping between the scalable vector IR type and
corresponding SelectionDAG ValueTypes.
Reviewers: craig.topper, jeroen.dobbelaere, fhahn, rengolin, greened, rovka
Reviewed By: greened
Differential Revision: https://reviews.llvm.org/D47770
llvm-svn: 367832
For consistency with normal instructions and clarity when reading IR,
it's best to print the %0, %1, ... names of function arguments in
definitions.
Also modifies the parser to accept IR in that form for obvious reasons.
llvm-svn: 367755
ThreadSafeModule/ThreadSafeContext are used to manage lifetimes and locking
for LLVMContexts in ORCv2. Prior to this patch contexts were locked as soon
as an associated Module was emitted (to be compiled and linked), and were not
unlocked until the emit call returned. This could lead to deadlocks if
interdependent modules that shared contexts were compiled on different threads:
when, during emission of the first module, the dependence was discovered the
second module (which would provide the required symbol) could not be emitted as
the thread emitting the first module still held the lock.
This patch eliminates this possibility by moving to a finer-grained locking
scheme. Each client holds the module lock only while they are actively operating
on it. To make this finer grained locking simpler/safer to implement this patch
removes the explicit lock method, 'getContextLock', from ThreadSafeModule and
replaces it with a new method, 'withModuleDo', that implicitly locks the context,
calls a user-supplied function object to operate on the Module, then implicitly
unlocks the context before returning the result.
ThreadSafeModule TSM = getModule(...);
size_t NumFunctions = TSM.withModuleDo(
[](Module &M) { // <- context locked before entry to lambda.
return M.size();
});
Existing ORCv2 layers that operate on ThreadSafeModules are updated to use the
new method.
This method is used to introduce Module locking into each of the existing
layers.
llvm-svn: 367686
The unit tests in BasicAliasAnalysisTest use the alias analysis API
directly and do not call setAAResults to initalize AAR. This gives a
valgrind error "Conditional Jump depends on unitialized variable".
On most buildbots the variable is nullptr, but in some cases it can be
non nullptr leading to seemingly random failures.
These tests were disabled in r366986. With the initialization they can be
enabled again.
Fixes PR42719
Differential Revision: https://reviews.llvm.org/D65568
llvm-svn: 367662
Summary:
LoopSimplify is preserved in the legacy pass manager, but not in the new pass manager.
Update LoopSimplify to preserve MemorySSA conditionally when the analysis is available (same behavior as the legacy pass manager).
Reviewers: chandlerc
Subscribers: mehdi_amini, jlebar, Prazek, george.burgess.iv, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65418
llvm-svn: 367594
Adds a method which, when called with function.getArg(i), returns an
Argument* to the i'th argument.
Patch by Henry Wildermuth
Differential Revision: https://reviews.llvm.org/D64925
llvm-svn: 367576
Added AddOverflow, SubOverflow and MulOverflow to compute truncated results and return a flag indicating whether overflow occured.
Differential Revision: https://reviews.llvm.org/D65494
llvm-svn: 367470
Summary:
This patch introduces a type to straighten LLVM's alignment management.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
The next step is to use this type throughout LLVM
Reviewers: jfb, jakehehrlich
Subscribers: mgorny, mgrang, dexonsmith, llvm-commits, courbet
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64790
llvm-svn: 367393
Summary: The minimum compilers support all have alignas, and we don't use LLVM_ALIGNAS anywhere anymore. This also removes an MSVC diagnostic which, according to the comment above, isn't relevant anymore.
Reviewers: rnk
Subscribers: mgorny, jkorous, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65458
llvm-svn: 367383
Add a new serializer, using a binary format based on the LLVM bitstream
format.
This format provides a way to serialize the remarks in two modes:
1) Separate mode: the metadata is separate from the remark entries.
2) Standalone mode: the metadata and the remark entries are in the same
file.
The format contains:
* a meta block: container version, container type, string table,
external file path, remark version
* a remark block: type, remark name, pass name, function name, debug
file, debug line, debug column, hotness, arguments (key, value, debug
file, debug line, debug column)
A string table is required for this format, which will be dumped in the
meta block to be consumed before parsing the remark blocks.
On clang itself, we noticed a size reduction of 13.4x compared to YAML,
and a compile-time reduction of between 1.7% and 3.5% on CTMark.
Differential Revision: https://reviews.llvm.org/D63466
Original llvm-svn: 367364
Revert llvm-svn: 367370
llvm-svn: 367372
Add a new serializer, using a binary format based on the LLVM bitstream
format.
This format provides a way to serialize the remarks in two modes:
1) Separate mode: the metadata is separate from the remark entries.
2) Standalone mode: the metadata and the remark entries are in the same
file.
The format contains:
* a meta block: container version, container type, string table,
external file path, remark version
* a remark block: type, remark name, pass name, function name, debug
file, debug line, debug column, hotness, arguments (key, value, debug
file, debug line, debug column)
A string table is required for this format, which will be dumped in the
meta block to be consumed before parsing the remark blocks.
On clang itself, we noticed a size reduction of 13.4x compared to YAML,
and a compile-time reduction of between 1.7% and 3.5% on CTMark.
Differential Revision: https://reviews.llvm.org/D63466
llvm-svn: 367364
The default mode is separate, where the metadata is serialized
separately from the remarks.
Another mode is the standalone mode, where the metadata is serialized
before the remarks, on the same stream.
llvm-svn: 367328
I removed all uses of AlignedCharArray since the minimum MSVC version can handle
alignas on char arrays correctly. We can therefore remove AlignedCharArray.
This patch also updates AlignedCharArrayUnion to use C++11.
llvm-svn: 367282
Looks like one of the entries isn't found on windows. I'm investigating why.
In the meantime, I'll disable this part of the test on windows.
llvm-svn: 367280
This patch adds a VFS that can be overlaid on top of another VFS
to record file system accesses using the FileCollector.
This can help to gather files that are needed for reproducers.
Differential Revision: https://reviews.llvm.org/D65411
llvm-svn: 367278
This adds support to the yaml remark parser to be able to parse remarks
directly from the metadata.
This supports parsing separate metadata and following the external file
with the associated metadata, and also a standalone file containing
metadata + remarks all together.
Original llvm-svn: 367148
Revert llvm-svn: 367151
This has a fix for gcc builds.
llvm-svn: 367155
