During extraction, stale llvm.assume handles may be retained in the
original function. The setup is:
1) CodeExtractor unregisters assumptions in the blocks that are to be
extracted.
2) Extraction happens. There are now two functions: f1 and f1.extracted.
3) Leftover assumptions in f1 (/not/ removed as they were not in the set of
blocks to be extracted) now have affected-value llvm.assume handles in
f1.extracted.
When assumptions for a value used in f1 are looked up, ValueTracking can assert
as some of the handles are in the wrong function. To fix this, simply erase the
llvm.assume calls in the extracted function.
Alternatives include flushing the assumption cache in the original function, or
walking all values used in the original function to prune stale affected-value
handles. Both seem more expensive.
Testing: check-llvm, LNT run with -mllvm -hot-cold-split enabled
rdar://58460728
Factor out CodeExtractor's analysis of allocas (for shrinkwrapping
purposes), and allow the analysis to be reused.
This resolves a quadratic compile-time bug observed when compiling
AMDGPUDisassembler.cpp.o.
Pre-patch (Release + LTO clang):
```
---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---
176.5278 ( 57.8%) 0.4915 ( 18.5%) 177.0192 ( 57.4%) 177.4112 ( 57.3%) Hot Cold Splitting
```
Post-patch (ReleaseAsserts clang):
```
---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---
1.4051 ( 3.3%) 0.0079 ( 0.3%) 1.4129 ( 3.2%) 1.4129 ( 3.2%) Hot Cold Splitting
```
Testing: check-llvm, and comparing the AMDGPUDisassembler.cpp.o binary
pre- vs. post-patch.
An alternate approach is to hide CodeExtractorAnalysisCache from clients
of CodeExtractor, and to recompute the analysis from scratch inside of
CodeExtractor::extractCodeRegion(). This eliminates some redundant work
in the shrinkwrapping legality check. However, some clients continue to
exhibit O(n^2) compile time behavior as computing the analysis is O(n).
rdar://55912966
Differential Revision: https://reviews.llvm.org/D68616
llvm-svn: 374089
Summary: Assumption cache's self-updating mechanism does not correctly handle the case when blocks are extracted from the function by the CodeExtractor. As a result function's assumption cache may have stale references to the llvm.assume calls that were moved to the outlined function. This patch fixes this problem by removing extracted llvm.assume calls from the function’s assumption cache.
Reviewers: hfinkel, vsk, fhahn, davidxl, sanjoy
Reviewed By: hfinkel, vsk
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57215
llvm-svn: 353500
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Lifetime markers which reference inputs to the extraction region are not
safe to extract. Example ('rhs' will be extracted):
```
entry:
+------------+
| x = alloca |
| y = alloca |
+------------+
/ \
lhs: rhs:
+-------------------+ +-------------------+
| lifetime_start(x) | | lifetime_start(x) |
| use(x) | | lifetime_start(y) |
| lifetime_end(x) | | use(x, y) |
| lifetime_start(y) | | lifetime_end(y) |
| use(y) | | lifetime_end(x) |
| lifetime_end(y) | +-------------------+
+-------------------+
```
Prior to extraction, the stack coloring pass sees that the slots for 'x'
and 'y' are in-use at the same time. After extraction, the coloring pass
infers that 'x' and 'y' are *not* in-use concurrently, because markers
from 'rhs' are no longer available to help decide otherwise.
This leads to a miscompile, because the stack slots actually are in-use
concurrently in the extracted function.
Fix this by moving lifetime start/end markers for memory regions defined
in the calling function around the call to the extracted function.
Fixes llvm.org/PR39671 (rdar://45939472).
Differential Revision: https://reviews.llvm.org/D55967
llvm-svn: 350420
If a PHI node out of extracted region has multiple incoming values from it,
split this PHI on two parts. First PHI has incomings only from region and
extracts with it (they are placed to the separate basic block that added to the
list of outlined), and incoming values in original PHI are replaced by first
PHI. Similar solution is already used in CodeExtractor for PHIs in entry block
(severSplitPHINodes method). It covers PR39433 bug.
Patch by Sergei Kachkov!
Differential Revision: https://reviews.llvm.org/D55018
llvm-svn: 348205
Summary:
The current default of appending "_"+entry block label to the new
extracted cold function breaks demangling. Change the deliminator from
"_" to "." to enable demangling. Because the header block label will
be empty for release compile code, use "extracted" after the "." when
the label is empty.
Additionally, add a mechanism for the client to pass in an alternate
suffix applied after the ".", and have the hot cold split pass use
"cold."+Count, where the Count is currently 1 but can be used to
uniquely number multiple cold functions split out from the same function
with D53588.
Reviewers: sebpop, hiraditya
Subscribers: llvm-commits, erik.pilkington
Differential Revision: https://reviews.llvm.org/D53534
llvm-svn: 345178
This is a CodeExtractor improvement which adds support for extracting blocks
which have exception handling constructs if that is legal to do. CodeExtractor
performs validation checks to ensure that extraction is legal when it finds
invoke instructions or EH pads (landingpad, catchswitch, or cleanuppad) in
blocks to be extracted.
I have also added an option to allow extraction of blocks with alloca
instructions, but no validation is done for allocas. CodeExtractor caller has
to validate it himself before allowing alloca instructions to be extracted.
By default allocas are still not allowed in extraction blocks.
Differential Revision: https://reviews.llvm.org/D45904
llvm-svn: 332151
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
Summary:
This patch extends the partial inliner to support inlining parts of
vararg functions, if the vararg handling is done in the outlined part.
It adds a `ForwardVarArgsTo` argument to InlineFunction. If it is
non-null, all varargs passed to the inlined function will be added to
all calls to `ForwardVarArgsTo`.
The partial inliner takes care to only pass `ForwardVarArgsTo` if the
varargs handing is done in the outlined function. It checks that vastart
is not part of the function to be inlined.
`test/Transforms/CodeExtractor/PartialInlineNoInline.ll` (already part
of the repo) checks we do not do partial inlining if vastart is used in
a basic block that will be inlined.
Reviewers: davide, davidxl, grosser
Reviewed By: davide, davidxl, grosser
Subscribers: gyiu, grosser, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D39607
llvm-svn: 318028
Added ability to estimate the entry count of the extracted function and
the branch probabilities of the exit branches.
Patch by River Riddle!
Differential Revision: https://reviews.llvm.org/D22744
llvm-svn: 277411
Added ability to estimate the entry count of the extracted function and
the branch probabilities of the exit branches.
Patch by River Riddle!
Differential Revision: https://reviews.llvm.org/D22744
llvm-svn: 277313
This lets you actually check to see if a block is valid before trying to
extract.
Patch by River Riddle!
Differential Revision: https://reviews.llvm.org/D22699
llvm-svn: 276846
Removed some unused headers, replaced some headers with forward class declarations.
Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'
Patch by Eugene Kosov <claprix@yandex.ru>
Differential Revision: http://reviews.llvm.org/D19219
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
llvm-svn: 240137
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)
Changes made by clang-tidy with minor tweaks.
llvm-svn: 215558
of the CodeExtractor utility. This allows speculatively computing input
and output sets to measure the likely size impact of the code
extraction.
These sets cannot be reused sadly -- we mutate the function prior to
forming the final sets used by the actual extraction.
The interface has been revamped slightly to make it easier to use
correctly by making the interface const and sinking the computation of
the number of exit blocks into the full extraction function and away
from the rest of this logic which just computed two output parameters.
llvm-svn: 156168
and expose it as a utility class rather than as free function wrappers.
The simple free-function interface works well for the bugpoint-specific
pass's uses of code extraction, but in an upcoming patch for more
advanced code extraction, they simply don't expose a rich enough
interface. I need to expose various stages of the process of doing the
code extraction and query information to decide whether or not to
actually complete the extraction or give up.
Rather than build up a new predicate model and pass that into these
functions, just take the class that was actually implementing the
functions and lift it up into a proper interface that can be used to
perform code extraction. The interface is cleaned up and re-documented
to work better in a header. It also is now setup to accept the blocks to
be extracted in the constructor rather than in a method.
In passing this essentially reverts my previous commit here exposing
a block-level query for eligibility of extraction. That is no longer
necessary with the more rich interface as clients can query the
extraction object for eligibility directly. This will reduce the number
of walks of the input basic block sequence by quite a bit which is
useful if this enters the normal optimization pipeline.
llvm-svn: 156163
