stop llvm-reduce from introducing undefs

Differential Revision: https://reviews.llvm.org/D128317

llvm-reduce: improve basic-blocks removal pass

When the single branch target of a block has been removed try updating
it to target a block that is kept (by scanning forward in the sequence)
instead

llvm-reduce: improve basic-blocks removal pass

When the single branch target of a block has been removed try updating
it to target a block that is kept (by scanning forward in the sequence)
instead of replacing the branch with a return instruction. Doing so
reduces the risk of breaking loop structures meaning that when the loop
is 'interesting' these reductions should have more blocks eliminated.

Differential Revision: https://reviews.llvm.org/D125766

show more ...

llvm-reduce: Fix variable name typo

llvm-reduce: Fix some copy-pasted comment errors

[NFC] Remove unnecessary "#include"s from header files

[llvm-reduce] Remove unnecessary loop.

After cd8aa234fdd2, there's no need to collect a vector of basic blocks
to keep first. Remove the first loop.

[llvm-reduce] Count chunks by running a preliminary reduction

Having a separate counting method runs the risk of a mismatch between
the actual reduction method and the counting method.

Instead, cre

[llvm-reduce] Count chunks by running a preliminary reduction

Having a separate counting method runs the risk of a mismatch between
the actual reduction method and the counting method.

Instead, create an Oracle that always returns true for shouldKeep(), run
the reduction, and count how many times shouldKeep() was called. The
module should not be modified if shouldKeep() always returns true.

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D113537

show more ...

[llvm-reduce] Use DenseSet instead of std::set (NFC).

When reducing functions with very large basic blocks (~ almost 1 million
BBs), the majority of time is spent maintaining the order in the std::s

[llvm-reduce] Use DenseSet instead of std::set (NFC).

When reducing functions with very large basic blocks (~ almost 1 million
BBs), the majority of time is spent maintaining the order in the std::set
for the basic blocks to keep.

In those cases, DenseSet<> is much more efficient. Use it instead.

show more ...

[llvm-reduce] Fix invalid reduction in basic-blocks delta pass

Previously, if the basic-blocks delta pass tried to remove a basic block
that was the last basic block in a function that did not have

[llvm-reduce] Fix invalid reduction in basic-blocks delta pass

Previously, if the basic-blocks delta pass tried to remove a basic block
that was the last basic block in a function that did not have external
or weak linkage, the resulting IR would become invalid. Since removing
the last basic block in a function is effectively identical to removing
the function body itself, we check explicitly for this case and if we
detect it, we run the same logic as in ReduceFunctionBodies.cpp

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D113486

show more ...

[llvm-reduce] optimize extractFromModule functions

The extractBasicBlocksFromModule, extractInstrFromModule, and other
similar functions previously performed very poorly when the number of
such elem

[llvm-reduce] optimize extractFromModule functions

The extractBasicBlocksFromModule, extractInstrFromModule, and other
similar functions previously performed very poorly when the number of
such elements in the program to reduce was very high. Previously, we
were creating the set which caches elements to keep by looping through
all elements in the module and adding them to the set. However, since
std::set is an ordered set, this introduces a massive amount of
rebalancing if the order of elements in the program and the order of
their pointers in memory are not the same.

The solution is straightforward: first put all the elements to be kept
in a vector, then use the constructor for std::set which takes a pair of
iterators over a collection. This constructor is optimized to avoid
doing unnecessary work when initializing large sets.

Also in this change, we pass BBsToKeep set to functions
replaceBranchTerminator and removeUninterestingBBsFromSwitch as a const
reference rather than passing it by value. This ought to prevent the
need to copy the collection each time these functions are called, which
is expensive if the collection is large.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D112757

show more ...

[NFC][llvm-reduce] Cleanup types

Use Module& wherever possible.
Since every reduction immediately turns Chunks into an Oracle, directly pass Oracle instead.

Reviewed By: hans

Differential Revision

[NFC][llvm-reduce] Cleanup types

Use Module& wherever possible.
Since every reduction immediately turns Chunks into an Oracle, directly pass Oracle instead.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D111122

show more ...

[llvm-reduce] Add header guards and fix clang-tidy warnings

Add header guards and fix other clang-tidy warnings in .h files.
Also align misaligned header docs

Reviewed By: aeubanks

Differential Re

[llvm-reduce] Add header guards and fix clang-tidy warnings

Add header guards and fix other clang-tidy warnings in .h files.
Also align misaligned header docs

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D99634

show more ...

[llvm-reduce] Create returns with undef values for non-void functions.

Currently replaceBranchTerminator/removeUninterestingBBsFromSwitch
always creates `ret void` instructions if no successor is in

[llvm-reduce] Create returns with undef values for non-void functions.

Currently replaceBranchTerminator/removeUninterestingBBsFromSwitch
always creates `ret void` instructions if no successor is in the chunk.

This results in invalid IR for functions with non-void return types,
which makes those reductions unfeasible. Instead, create `ret ty undef`
for functions with non-void return types.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D86849

show more ...

[Reduce] Basic block reduction: do properly handle invoke insts (PR46818)

Terminator may have returned value, so we need to replace uses,
and in general handle invoke as a branch inst.

I'm not sure

[Reduce] Basic block reduction: do properly handle invoke insts (PR46818)

Terminator may have returned value, so we need to replace uses,
and in general handle invoke as a branch inst.

I'm not sure this is the best handling, but IMO poorly reduced
input is much better than crashing reduction tool.
A (previously-crashing!) test added.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46818

show more ...

[NFCI][llvm-reduce] Cleanup Delta passes to use Oracle abstraction

Summary:
I think, this results in much more understandable/readable flow.
At least the original logic was perhaps the most hard thi

[NFCI][llvm-reduce] Cleanup Delta passes to use Oracle abstraction

Summary:
I think, this results in much more understandable/readable flow.
At least the original logic was perhaps the most hard thing for me to grasp when taking an initial look on the delta passes.

Reviewers: nickdesaulniers, dblaikie, diegotf, george.burgess.iv

Reviewed By: nickdesaulniers

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83287

show more ...

llvm-reduce: Follow-up to 372280, now with more-better msan fixing

llvm-svn: 372349

llvm-reduce: Avoid use-after-free when removing a branch instruction

Found my msan buildbot & pointed out by Nico Weber - thanks Nico!

llvm-svn: 372280

llvm-reduce: Remove inaccurate doxy comment about a return that isn't returned

Addressing post-commit code review feedback from Dávid Bolvanský -
thanks!

llvm-svn: 372271

llvm-reduce: Fix inconsistencies between int/unsigned usage (standardize on int)

llvm-svn: 372270

llvm-reduce: Add pass to reduce basic blocks

Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D66320

llvm-svn: 372264