Change BasicBlock::removePredecessor to optionally return a vector of
instructions which might be dead. Use this in ConstantFoldTerminator to
delete them if they are dead.
Reapply with a bug fix: don't drop the "!KeepOneInputPHIs" argument when
removePredecessor calls PHINode::removeIncomingValue.
Differential Revision: https://reviews.llvm.org/D80206
Change BasicBlock::removePredecessor to optionally return a vector of
instructions which might be dead. Use this in ConstantFoldTerminator to
delete them if they are dead.
Differential Revision: https://reviews.llvm.org/D80206
This is the second attempt at landing this patch, after fixing the
KeepOneInputPHIs behaviour to also keep zero input PHIs.
Differential Revision: https://reviews.llvm.org/D80141
r119493 protected against PHINode::hasConstantValue returning the PHI
node itself, but a later fix in r159687 means that can never happen, so
the workarounds are no longer required.
r2694 fixed a bug where removePredecessor could create IR with a use not
dominated by its def in a self loop. But this could only happen in an
unreachable loop, and since that time the rules have been relaxed so
that defs don't have to dominate uses in unreachable code, so the fix is
unnecessary. The regression test added in r2691 still stands.
Differential Revision: https://reviews.llvm.org/D80128
Summary:
Rename `succ_const_iterator` to `const_succ_iterator` and
`succ_const_range` to `const_succ_range` for consistency with the
predecessor iterators, and the corresponding iterators in
MachineBasicBlock.
Reviewers: nicholas, dblaikie, nlewycky
Subscribers: hiraditya, bmahjour, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75952
Essentially, fold OrderedBasicBlock into BasicBlock, and make it
auto-invalidate the instruction ordering when new instructions are
added. Notably, we don't need to invalidate it when removing
instructions, which is helpful when a pass mostly delete dead
instructions rather than transforming them.
The downside is that Instruction grows from 56 bytes to 64 bytes. The
resulting LLVM code is substantially simpler and automatically handles
invalidation, which makes me think that this is the right speed and size
tradeoff.
The important change is in SymbolTableTraitsImpl.h, where the numbering
is invalidated. Everything else should be straightforward.
We probably want to implement a fancier re-numbering scheme so that
local updates don't invalidate the ordering, but I plan for that to be
future work, maybe for someone else.
Reviewed By: lattner, vsk, fhahn, dexonsmith
Differential Revision: https://reviews.llvm.org/D51664
Blindly following unique-successors chain appeared to be a bad idea.
In a degenerate case when block jumps to itself that goes into endless loop.
Discovered this problem when playing with additional changes,
managed to reproduce it on existing LoopPredication code.
Fix by checking a "visited" set while iterating through unique successors.
Reviewed By: skatkov
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72908
It appears to be rather useful when analyzing Loops with multiple
deoptimizing exits, perhaps merged ones.
For now it is used in LoopPredication, will be adding more uses
in other loop passes.
Reviewers: asbirlea, fhahn, skatkov, spatel, reames
Reviewed By: reames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72754
The insertion of an unconditional branch during FastISel can differ depending on
building with or without debug information. This happens because FastISel::fastEmitBranch
emits an unconditional branch depending on the size of the current basic block
without distinguishing between debug and non-debug instructions.
This patch fixes this issue by ignoring debug instructions when getting the size
of the basic block.
Reviewers: aprantl
Reviewed By: aprantl
Subscribers: ormris, aprantl, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67703
llvm-svn: 372389
Thus it does not assume that the old basic block is the basic block
for which we are looking at successors.
Not reviewed, but seems rather trivial, in line with the rest of
previous few patches.
llvm-svn: 359997
Summary:
It is a common thing to loop over every `PHINode` in some `BasicBlock`
and change old `BasicBlock` incoming block to a new `BasicBlock` incoming block.
`replaceSuccessorsPhiUsesWith()` already had code to do that,
it just wasn't a function.
So outline it into a new function, and use it.
Reviewers: chandlerc, craig.topper, spatel, danielcdh
Reviewed By: craig.topper
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61013
llvm-svn: 359996
Summary:
There is `PHINode::getBasicBlockIndex()`, `PHINode::setIncomingBlock()`
and `PHINode::getNumOperands()`, but no function to replace every
specified `BasicBlock*` predecessor with some other specified `BasicBlock*`.
Clearly, there are a lot of places that could use that functionality.
Reviewers: chandlerc, craig.topper, spatel, danielcdh
Reviewed By: craig.topper
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61011
llvm-svn: 359995
as long as their uses does not contain calls to functions that capture
the argument (potentially allowing the blockaddress to "escape" the
lifetime of the caller).
TODO:
- add more tests
- fix crash in llvm::updateCGAndAnalysisManagerForFunctionPass when
invoking Transforms/Inline/blockaddress.ll
llvm-svn: 354079
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
Instruction::isLifetimeStartOrEnd() checks whether an Instruction is an
llvm.lifetime.start or an llvm.lifetime.end intrinsic.
This was suggested as a cleanup in D55967.
Differential Revision: https://reviews.llvm.org/D56019
llvm-svn: 349964
Add methods to BasicBlock which make it easier to efficiently check
whether a block has N (or more) predecessors.
This can be more efficient than using pred_size(), which is a linear
time operation.
We might consider adding similar methods for successors. I haven't done
so in this patch because succ_size() is already O(1).
With this patch applied, I measured a 0.065% compile-time reduction in
user time for running `opt -O3` on the sqlite3 amalgamation (30 trials).
The change in mergeStoreIntoSuccessor alone saves 45 million linked list
iterations in a stage2 Release build of llc.
See llvm.org/PR39702 for a harder but more general way of achieving
similar results.
Differential Revision: https://reviews.llvm.org/D54686
llvm-svn: 347256
This removes the primary remaining API producing `TerminatorInst` which
will reduce the rate at which code is introduced trying to use it and
generally make it much easier to remove the remaining APIs across the
codebase.
Also clean up some of the stragglers that the previous mechanical update
of variables missed.
Users of LLVM and out-of-tree code generally will need to update any
explicit variable types to handle this. Replacing `TerminatorInst` with
`Instruction` (or `auto`) almost always works. Most of these edits were
made in prior commits using the perl one-liner:
```
perl -i -ple 's/TerminatorInst(\b.* = .*getTerminator\(\))/Instruction\1/g'
```
This also my break some rare use cases where people overload for both
`Instruction` and `TerminatorInst`, but these should be easily fixed by
removing the `TerminatorInst` overload.
llvm-svn: 344504
by `getTerminator()` calls instead be declared as `Instruction`.
This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).
llvm-svn: 344502
`isExceptionalTermiantor` and implement it for opcodes as well following
the common pattern in `Instruction`.
Part of removing `TerminatorInst` from the `Instruction` type hierarchy
to make it easier to share logic and interfaces between instructions
that are both terminators and not terminators.
llvm-svn: 340699
The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.
The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.
Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.
This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html
There will be a series of much more mechanical changes following this
one to complete this move.
Differential Revision: https://reviews.llvm.org/D47467
llvm-svn: 340698
This addresses post-commit feedback about the name 'skipDebugInfo' being
misleading. This name could be interpreted as meaning 'a function that
skips instructions with debug locations'.
The new name, 'skipDebugIntrinsics', makes it clear that this function
only skips debug info intrinsics.
Thanks to Adrian Prantl for pointing this out!
llvm-svn: 335667
This patch introduces two helpers to make it easier to ignore debug
intrinsics:
- Instruction::getNextNonDebugInstruction()
This is just like Instruction::getNextNode(), except that it skips debug
info.
- skipDebugInfo(BasicBlock::iterator)
A free function which advances a BasicBlock iterator past any debug
info. This is a no-op when the iterator already points to a non-debug
instruction.
Part of: llvm.org/PR37728
Related to: https://reviews.llvm.org/D47874
Differential Revision: https://reviews.llvm.org/D48305
llvm-svn: 335083
Summary:
Currently the block frequency analysis is an approximation for irreducible
loops.
The new irreducible loop metadata is used to annotate the irreducible loop
headers with their header weights based on the PGO profile (currently this is
approximated to be evenly weighted) and to help improve the accuracy of the
block frequency analysis for irreducible loops.
This patch is a basic support for this.
Reviewers: davidxl
Reviewed By: davidxl
Subscribers: mehdi_amini, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D39028
llvm-svn: 317278
block.
This allows writing much more natural and readable range based for loops
directly over the PHI nodes. It also takes advantage of the same tricks
for terminating the sequence as the hand coded versions.
I've replaced one example of this mostly to showcase the difference and
I've added a unit test to make sure the facilities really work the way
they're intended. I want to use this inside of SimpleLoopUnswitch but it
seems generally nice.
Differential Revision: https://reviews.llvm.org/D33533
llvm-svn: 303964
Summary:
During post-commit review of a previous change I made it was pointed out that const casting 'this' is technically a bad practice. This patch re-implements all of the methods in BasicBlock that do this to use the const BasicBlock version and const_cast the return value instead.
I think there are still many other classes that do similar things. I may look at more in the future.
Reviewers: dblaikie
Reviewed By: dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31377
llvm-svn: 298827
The ValueSymbolTable is used to detect name conflict and rename
instructions automatically. This is not needed when the value
names are automatically discarded by the LLVMContext.
No functional change intended, just saving a little bit of memory.
This is a recommit of r281806 after fixing the accessor to return
a pointer instead of a reference and updating all the call-sites.
llvm-svn: 281813
Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
basic block including lifetime intrinsics as well as phi nodes and
unconditional branch into its successor or predecessor(s).
If successor of empty block has single predecessor, all contents including
lifetime intrinsics are sinked into the successor. Otherwise, they are
hoisted into its predecessor(s) and then merged into the predecessor(s).
Patch by Josh Yoon <josh.yoon@samsung.com>!
Differential Revision: http://reviews.llvm.org/D19257
llvm-svn: 268254
Summary:
This intrinsic, together with deoptimization operand bundles, allow
frontends to express transfer of control and frame-local state from
one (typically more specialized, hence faster) version of a function
into another (typically more generic, hence slower) version.
In languages with a fully integrated managed runtime this intrinsic can
be used to implement "uncommon trap" like functionality. In unmanaged
languages like C and C++, this intrinsic can be used to represent the
slow paths of specialized functions.
Note: this change does not address how `@llvm.experimental_deoptimize`
is lowered. That will be done in a later change.
Reviewers: chandlerc, rnk, atrick, reames
Subscribers: llvm-commits, kmod, mjacob, maksfb, mcrosier, JosephTremoulet
Differential Revision: http://reviews.llvm.org/D17732
llvm-svn: 263281
Stop using `getNodePtrUnchecked()` when building IR. Eventually a
dereference will be required to get at the downcast node, since the
iterator will only store an `ilist_node_base` of some sort.
This should have no functionality change for now, but is a path towards
removing some more UB from ilist.
llvm-svn: 261495
Stop converting implicitly between iterators and pointers/references in
lib/IR. For convenience, I've added a `getIterator()` accessor to
`ilist_node` so that callers don't need to know how to spell the
iterator class (i.e., they can use `X.getIterator()` instead of
`Function::iterator(X)`).
I'll eventually disallow these implicit conversions entirely, but
there's a lot of code, so it doesn't make sense to do it all in one
patch. One library or so at a time.
Why? To root out cases of `getNextNode()` and `getPrevNode()` being
used in iterator logic. The design of `ilist` makes that invalid when
the current node could be at the back of the list, but it happens to
"work" right now because of a bug where those functions never return
`nullptr` if you're using a half-node sentinel. Before I can fix the
function, I have to remove uses of it that rely on it misbehaving.
(Maybe the function should just be deleted anyway? But I don't want
deleting it -- potentially a huge project -- to block fixing
ilist/iplist.)
llvm-svn: 249782
Create `SymbolTableList`, a wrapper around `iplist` for lists that
automatically manage a symbol table. This commit reduces a ton of code
duplication between the six traits classes that were used previously.
As a drive by, reduce the number of template parameters from 2 to 1 by
using a SymbolTableListParentType metafunction (I originally had this as
a separate commit, but it touched most of the same lines so I squashed
them).
I'm in the process of trying to remove the UB in `createSentinel()` (see
the FIXMEs I added for `ilist_embedded_sentinel_traits` and
`ilist_half_embedded_sentinel_traits`). My eventual goal is to separate
the list logic into a base class layer that knows nothing about (and
isn't templated on) the downcasted nodes -- removing the need to invoke
UB -- but for now I'm just trying to get a handle on all the current use
cases (and cleaning things up as I see them).
Besides these six SymbolTable lists, there are two others that use the
addNode/removeNode/transferNodes() hooks: the `MachineInstruction` and
`MachineBasicBlock` lists. Ideally there'll be a way to factor these
hooks out of the low-level API entirely, but I'm not quite there yet.
llvm-svn: 249602
After r244074, we now have a successors() method to iterate over
all the successors of a TerminatorInst. This commit changes a bunch
of eligible loops to use it.
llvm-svn: 244260
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support. Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.
Differential Revision: http://reviews.llvm.org/D11097
llvm-svn: 243766
Jay Foad