The EP_CGSCCOptimizerLate extension point allows adding CallGraphSCC
passes at the end of the main CallGraphSCC passes and before any
function simplification passes run by CGPassManager.
Patch by Gor Nishanov!
Differential Revision: https://reviews.llvm.org/D22897
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276953 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Adding a flag to diable GVN Hoisting by default.
Note: The GVN Hoist Pass causes some Halide tests to hang. Halide will disable the pass while investigating.
Reviewers: llvm-commits, chandlerc, spop, dberlin
Subscribers: mehdi_amini
Differential Revision: https://reviews.llvm.org/D22639
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276479 91177308-0d34-0410-b5e6-96231b3b80d8
Just because we can constant fold the result of an instruction does not
imply that we can delete the instruction. It may have side effects.
This fixes PR28655.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276389 91177308-0d34-0410-b5e6-96231b3b80d8
We skipped over ReturnInsts which didn't return an argument which would
lead us to incorrectly conclude that an argument returned by another
ReturnInst was 'returned'.
This reverts commit r275756.
This fixes PR28610.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276008 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts also r275029, "Update Clang tests after adding inference for the returned argument attribute"
It broke LTO build. Seems miscompilation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275756 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
To enable profile-guided indirect call promotion in ThinLTO mode, we
simply add call graph edges for each profitable target from the profile
to the summaries, then the summary-guided importing will consider the
callee for importing as usual.
Also we need to enable the indirect call promotion pass creation in the
PassManagerBuilder when PerformThinLTO=true (we are in the ThinLTO
backend), so that the newly imported functions are considered for
promotion in the backends.
The IC promotion profiles refer to callees by GUID, which required
adding GUIDs to the per-module VST in bitcode (and assigning them
valueIds similar to how they are assigned valueIds in the combined
index).
Reviewers: mehdi_amini, xur
Subscribers: mehdi_amini, davidxl, llvm-commits
Differential Revision: http://reviews.llvm.org/D21932
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275707 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r275042; the initial commit triggered self-hosting failures
on ARM/AArch64. James Molloy identified the problematic backend code, which has
been disabled in r275677. Trying again...
Original commit message:
Let FuncAttrs infer the 'returned' argument attribute
A function can have one argument with the 'returned' attribute, indicating that
the associated argument is always the return value of the function. Add
FuncAttrs inference logic.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275678 91177308-0d34-0410-b5e6-96231b3b80d8
This patch adds a selected set of cleanup passes including a pre-inline pass
before LLVM IR PGO instrumentation. The inline is only intended to apply those
obvious/trivial ones before instrumentation so that much less instrumentation
is needed to get better profiling information. This will drastically improve
the instrumented code performance for large C++ applications. Another benefit
is the context sensitive counts that can potentially improve the PGO
optimization.
Differential Revision: http://reviews.llvm.org/D21405
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275588 91177308-0d34-0410-b5e6-96231b3b80d8
This pass hoists duplicated computations in the program. The primary goal of
gvn-hoist is to reduce the size of functions before inline heuristics to reduce
the total cost of function inlining.
Pass written by Sebastian Pop, Aditya Kumar, Xiaoyu Hu, and Brian Rzycki.
Important algorithmic contributions by Daniel Berlin under the form of reviews.
Differential Revision: http://reviews.llvm.org/D19338
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275561 91177308-0d34-0410-b5e6-96231b3b80d8
This pass hoists duplicated computations in the program. The primary goal of
gvn-hoist is to reduce the size of functions before inline heuristics to reduce
the total cost of function inlining.
Pass written by Sebastian Pop, Aditya Kumar, Xiaoyu Hu, and Brian Rzycki.
Important algorithmic contributions by Daniel Berlin under the form of reviews.
Differential Revision: http://reviews.llvm.org/D19338
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275401 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
It's useful to have some visibility about which call sites are devirtualized,
especially for debug purposes. Another use case is a regression test on the
application side (like, Chromium).
Reviewers: pcc
Differential Revision: http://reviews.llvm.org/D22252
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275145 91177308-0d34-0410-b5e6-96231b3b80d8
There's a little bit of churn in this patch because the initialization
mechanism is now shared between the old and the new PM. Other than
that, it's just a pretty mechanical translation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275082 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
For sample-based PGO, using BFI to calculate callsite count is sometime not accurate. This is because with sampling based approach, if a callsite resides in a hot loop deeply nested in a bunch of cold branches, the callsite's BFI frequency would be inaccurately calculated due to lack of samples in the cold branch.
E.g.
if (A1 && A2 && A3 && ..... && A10) {
for (i=0; i < 100000000; i++) {
callsite();
}
}
Assume that A1 to A100 are all 100% taken, and callsite has 1000 samples and thus is considerred hot. Because the loop's trip count is huge, it's normal that all branches outside the loop has no sample at all. As a result, we can only use static branch probability to derive the the frequency of the loop header. Assuming that static heuristic thinks each branch is 50% taken, then the count calculated from BFI will be 1/(2^10) of the actual value.
In order to get more accurate callsite count, we directly annotate the weight on the call instruction, and directly use it when checking callsite hotness.
Note that this mechanism can also be shared by instrumentation based callsite hotness analysis. The side benefit is that it breaks the dependency from Inliner to BFI as call count is embedded in the IR.
Reviewers: davidxl, eraman, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D22118
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275073 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: Handle the case when there is only one incoming/outgoing edge for a visited basic block: use the block weight to adjust edge weight even when the edge has been visited before. This can help reduce inaccuracies introduced by incorrect basic block profile, as shown in the updated unittest.
Reviewers: davidxl, dnovillo
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D22180
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275072 91177308-0d34-0410-b5e6-96231b3b80d8
A function can have one argument with the 'returned' attribute, indicating that
the associated argument is always the return value of the function. Add
FuncAttrs inference logic.
Differential Revision: http://reviews.llvm.org/D22202
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275027 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This way the metadata will be only generated when asserts enabled,
or when -enable-import-metadata specified
FIXED missing colon on requires.
Reviewers: tejohnson, eraman, mehdi_amini
Subscribers: mehdi_amini, llvm-commits
Differential Revision: http://reviews.llvm.org/D22167
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274947 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This way the metadata will be only generated when asserts enabled,
or when -enable-import-metadata specified
Reviewers: tejohnson, eraman, mehdi_amini
Subscribers: mehdi_amini, llvm-commits
Differential Revision: http://reviews.llvm.org/D22167
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274938 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: As we will move to use uniformed hotness check in inliner, we do not need inline hints in SampleProfile pass any more.
Reviewers: dnovillo, davidxl
Subscribers: eraman, llvm-commits
Differential Revision: http://reviews.llvm.org/D19287
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274918 91177308-0d34-0410-b5e6-96231b3b80d8
Added metadata to be able to make statistics on how many functions
that have been imported have been removed. Also module name might
be helpfull when debugging.
Reviewers: tejohnson, eraman
Subscribers: mehdi_amini, llvm-commits
Differential Revision: http://reviews.llvm.org/D21943
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274668 91177308-0d34-0410-b5e6-96231b3b80d8
StratifiedSets (as implemented) is very fast, but its accuracy is also
limited. If we take a more aggressive andersens-like approach, we can be
way more accurate, but we'll also end up being slower.
So, we've decided to split CFLAA into CFLSteensAA and CFLAndersAA.
Long-term, we want to end up in a place where CFLSteens is queried
first; if it can provide an answer, great (since queries are basically
map lookups). Otherwise, we'll fall back to CFLAnders, BasicAA, etc.
This patch splits everything out so we can try to do something like
that when we get a reasonable CFLAnders implementation.
Patch by Jia Chen.
Differential Revision: http://reviews.llvm.org/D21910
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274589 91177308-0d34-0410-b5e6-96231b3b80d8
This actually uncovered a surprisingly large chain of ultimately unused
TLI args.
From what I can gather, this argument is a remnant of when
isKnownNonNull would look at the TLI directly.
The current approach seems to be that InferFunctionAttrs runs early in
the pipeline and uses TLI to annotate the TLI-dependent non-null
information as return attributes.
This also removes the dependence of functionattrs on TLI altogether.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274455 91177308-0d34-0410-b5e6-96231b3b80d8
This pass hoists duplicated computations in the program. The primary goal of
gvn-hoist is to reduce the size of functions before inline heuristics to reduce
the total cost of function inlining.
Pass written by Sebastian Pop, Aditya Kumar, Xiaoyu Hu, and Brian Rzycki.
Important algorithmic contributions by Daniel Berlin under the form of reviews.
Differential Revision: http://reviews.llvm.org/D19338
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274305 91177308-0d34-0410-b5e6-96231b3b80d8
SimplifyCFG had logic to insert calls to llvm.trap for two very
particular IR patterns: stores and invokes of undef/null.
While InstCombine canonicalizes certain undefined behavior IR patterns
to stores of undef, phase ordering means that this cannot be relied upon
in general.
There are much better tools than llvm.trap: UBSan and ASan.
N.B. I could be argued into reverting this change if a clear argument as
to why it is important that we synthesize llvm.trap for stores, I'd be
hard pressed to see why it'd be useful for invokes...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273778 91177308-0d34-0410-b5e6-96231b3b80d8
This intrinsic safely loads a function pointer from a virtual table pointer
using type metadata. This intrinsic is used to implement control flow integrity
in conjunction with virtual call optimization. The virtual call optimization
pass will optimize away llvm.type.checked.load intrinsics associated with
devirtualized calls, thereby removing the type check in cases where it is
not needed to enforce the control flow integrity constraint.
This patch also introduces the capability to copy type metadata between
global variables, and teaches the virtual call optimization pass to do so.
Differential Revision: http://reviews.llvm.org/D21121
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273756 91177308-0d34-0410-b5e6-96231b3b80d8
The bitset metadata currently used in LLVM has a few problems:
1. It has the wrong name. The name "bitset" refers to an implementation
detail of one use of the metadata (i.e. its original use case, CFI).
This makes it harder to understand, as the name makes no sense in the
context of virtual call optimization.
2. It is represented using a global named metadata node, rather than
being directly associated with a global. This makes it harder to
manipulate the metadata when rebuilding global variables, summarise it
as part of ThinLTO and drop unused metadata when associated globals are
dropped. For this reason, CFI does not currently work correctly when
both CFI and vcall opt are enabled, as vcall opt needs to rebuild vtable
globals, and fails to associate metadata with the rebuilt globals. As I
understand it, the same problem could also affect ASan, which rebuilds
globals with a red zone.
This patch solves both of those problems in the following way:
1. Rename the metadata to "type metadata". This new name reflects how
the metadata is currently being used (i.e. to represent type information
for CFI and vtable opt). The new name is reflected in the name for the
associated intrinsic (llvm.type.test) and pass (LowerTypeTests).
2. Attach metadata directly to the globals that it pertains to, rather
than using the "llvm.bitsets" global metadata node as we are doing now.
This is done using the newly introduced capability to attach
metadata to global variables (r271348 and r271358).
See also: http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html
Differential Revision: http://reviews.llvm.org/D21053
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273729 91177308-0d34-0410-b5e6-96231b3b80d8
This is a convenience iterator that allows clients to enumerate the
GlobalObjects within a Module.
Also start using it in a few places where it is obviously the right thing
to use.
Differential Revision: http://reviews.llvm.org/D21580
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@273470 91177308-0d34-0410-b5e6-96231b3b80d8
