This macros is always defined: either 0 or 1. The correct pattern is to
use #if.
Re-apply #110185 with more fixes for debug build with the ABI breaking
checks disabled.
The sort used the block name as a tie-breaker, which will not work for
unnamed blocks and can result in a strict weak ordering violation.
Fix this by checking that all exiting blocks dominate the latch first,
which means that we have a total dominance order. This makes the code
structure here align with what optimizeLoopExits() does.
Fixes https://github.com/llvm/llvm-project/issues/108618.
This is a helper to avoid writing `getModule()->getDataLayout()`. I
regularly try to use this method only to remember it doesn't exist...
`getModule()->getDataLayout()` is also a common (the most common?)
reason why code has to include the Module.h header.
As part of the RemoveDIs project we need LLVM to insert instructions using
iterators wherever possible, so that the iterators can carry a bit of
debug-info. This commit implements some of that by updating the contents of
llvm/lib/Transforms/Utils to always use iterator-versions of instruction
constructors.
There are two general flavours of update:
* Almost all call-sites just call getIterator on an instruction
* Several make use of an existing iterator (scenarios where the code is
actually significant for debug-info)
The underlying logic is that any call to getFirstInsertionPt or similar
APIs that identify the start of a block need to have that iterator passed
directly to the insertion function, without being converted to a bare
Instruction pointer along the way.
Noteworthy changes:
* FindInsertedValue now takes an optional iterator rather than an
instruction pointer, as we need to always insert with iterators,
* I've added a few iterator-taking versions of some value-tracking and
DomTree methods -- they just unwrap the iterator. These are purely
convenience methods to avoid extra syntax in some passes.
* A few calls to getNextNode become std::next instead (to keep in the
theme of using iterators for positions),
* SeparateConstOffsetFromGEP has it's insertion-position field changed.
Noteworthy because it's not a purely localised spelling change.
All this should be NFC.
The integer case in genLoopLimit reduces down to a special case for narrowing the bitwidth of the limit, and then performing the same expansion we would for a pointer IV.
Differential Revision: https://reviews.llvm.org/D146638
Note that the comments being removed appear to be very out of sync with the actual code in question.
Differential Revision: https://reviews.llvm.org/D146468
This option is switched off by default, and it seems that it has never worked correctly.
What it basically does is: it remembers current BECount SCEV, and after all transforms
tries to validate some facts for it. However, between these two points this SCEV may
become invalid (e.g. because some SCEVUnknown it references may be deleted as dead
code). So basically it may work with broken pointers.
Besides, its implementation does strange things (e.g. forgetLoop) which are invasive and
may affect behavior in other parts of the system (specifically verification), concealing some
other problems. Another issue is that it may use SCEVCouldNotCompute object without
checking this.
The option is not used in any unit tests, and if switched on by default, the following tests
fail:
```
********************
Failed Tests (14):
LLVM :: Transforms/IndVarSimplify/2005-06-15-InstMoveCrash.ll
LLVM :: Transforms/IndVarSimplify/2007-06-06-DeleteDanglesPtr.ll
LLVM :: Transforms/IndVarSimplify/2008-10-03-CouldNotCompute.ll
LLVM :: Transforms/IndVarSimplify/2009-05-24-useafterfree.ll
LLVM :: Transforms/IndVarSimplify/2011-10-27-lftrnull.ll
LLVM :: Transforms/IndVarSimplify/ARM/code-size.ll
LLVM :: Transforms/IndVarSimplify/X86/deterministic-scev-verify.ll
LLVM :: Transforms/IndVarSimplify/X86/pr57187.ll
LLVM :: Transforms/IndVarSimplify/X86/verify-scev.ll
LLVM :: Transforms/IndVarSimplify/bbi-63564.ll
LLVM :: Transforms/IndVarSimplify/invalidate-modified-lcssa-phi.ll
LLVM :: Transforms/IndVarSimplify/loop-predication.ll
LLVM :: Transforms/IndVarSimplify/post-inc-range.ll
LLVM :: Transforms/IndVarSimplify/turn-to-invariant.ll
********************
Unexpectedly Passed Tests (1):
LLVM :: Transforms/IndVarSimplify/pr55689.ll
```
None of these looks like real problems found by verification, these are
bugs in the verifying code itself (such as use of deleted SCEVs and
SCEVCouldNotCompute's).
I think it all gives enough justification for its removal.
https://github.com/llvm/llvm-project/issues/61302
Differential Revision: https://reviews.llvm.org/D145894
Reviewed By: nikic
DFAJumpThreading
JumpThreading
LibCallsShrink
LoopVectorize
SLPVectorizer
DeadStoreElimination
AggressiveDCE
CorrelatedValuePropagation
IndVarSimplify
These are part of the optimization pipeline, of which the legacy version is deprecated and being removed.
The motivation is that 'createInvariantCond' unconditionally
builds icmp in the loop block, while it could always do it
in preheader. Build it in preheader instead.
Patch by Aleksandr Popov!
Differential Revision: https://reviews.llvm.org/D141994
Reviewed By: nikic
This patch does two things, both related to support of multi-exit loops with
many exits that have known symbolic max exit count. They can theoretically
go independently, but I don't know how to write a test showing separate
impact.
Part 1: `SkipLastIter` can be set to `true` not when a particular exit has exit
count same as the whole loop (and therefore it must exit on the last iteration),
but when the aggregate of first few exits has umin same as whole loop exit count.
It means that it's not known which of them will exit exactly, but one of them will.
Part 2: when `SkipLastIter` is set, and exit count is `umin(a, b, c)`, instead of
`umin(a, b, c) - 1` use `umin(a - 1, b - 1, c - 1)`. We don't care about overflows
here, but the further logic knows how to deal with umin by element, but the
`SCEVAddExpr` node will confuse it.
Differential Revision: https://reviews.llvm.org/D141361
Reviewed By: nikic
When exit by condition `C1` dominates exit by condition `C2`, and
max symbolic exit count for `C1` matches those for loop, we will
apply more optimistic logic to `C2` by setting `SkipLastIter` for it,
meaning that it will do 1 iteration less because the dominating branch
must exit on the last loop iteration.
But when we have a single exit by condition `C1 & C2`, we cannot
apply the same logic, because there is no dominating condition.
However, if we can prove that the symbolic max exit count of `C1 & C2`
matches those of `C1`, it means that for `C2` we can assume that it
doesn't matter on the last iteration (because the whole thing is `false`
because `C1` must be `false`). Therefore, in this situation, we can handle
`C2` as if it had `SkipLastIter`.
Differential Revision: https://reviews.llvm.org/D139934
Reviewed By: nikic
Similar to how `makeArrayRef` is deprecated in favor of deduction guides, do the
same for `makeMutableArrayRef`.
Once all of the places in-tree are using the deduction guides for
`MutableArrayRef`, we can mark `makeMutableArrayRef` as deprecated.
Differential Revision: https://reviews.llvm.org/D141814
This patch allows optimizeLoopExitWithUnknownExitCount to deal with
branches by conditions that are not immediately ICmp's, but aggregates
of ICmp's joined by arithmetic or logical AND/OR. Each ICmp is optimized
independently.
Differential Revision: https://reviews.llvm.org/D139832
Reviewed By: nikic
This patch updates propgatesPoison to take a Use as argument and
propagatesPoison now returns true if the passed in operand causes the
user to yield poison if the operand is poison
This allows propagating poison if the condition of a select is poison.
This helps improve results for programUndefinedIfUndefOrPoison.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D111643
There was a crippled version of this transform for Inverted predicate, so the same
query was done twice. Advanced version of this transform wasn't implemented for
inverted condition. Thus, the code was hard to read. The only real purpose of the
Inverted param was to make a simple isKnownPredicateAt query.
Instead if this, use evaluatePredicateAt to solve the task for both inverted and
non-inverted predicate. This slightly changes the order of queries, but effectively
it should save some time by avoiding duplicating queries, and simplifies the code a lot.
I also could not find any evidence that we ever eliminate anything with Inverted = true,
but conservatively preserved the current behavior. Maybe we can remove it and save
some compile time.
Differential Revision: https://reviews.llvm.org/D139814
Reviewed By: nikic
Old logic: when loop symbolic max exit count matched *exact* block exit count,
assume that all subsequent blocks will do 1 iteration less.
New logic: when loop symbolic max exit count matched *symbolic max* block exit count,
assume that all subsequent blocks will do 1 iteration less.
The new logic is still legal and is more permissive in situations when exact
block exit count is not known.
Differential Revision: https://reviews.llvm.org/D139692
Reviewed By: nikic
Additional SCEV verification highlighted a case where the cached loop
dispositions where incorrect after simplifying a phi node in IndVars.
Fix it by invalidating the phi before replacing it.
Fixes#58750
Moving an instruction can invalidate the cached block dispositions of
the corresponding SCEV. Invalidate the cached dispositions.
Also fixes a copy-paste error in forgetBlockAndLoopDispositions where
the start expression S was removed from BlockDispositions in the loop
but not the current values. This was also exposed by the new test case.
Fixes#58439.
isSafeToExpand() for addrecs depends on whether the SCEVExpander
will be used in CanonicalMode. At least one caller currently gets
this wrong, resulting in PR50506.
Fix this by a) making the CanonicalMode argument on the freestanding
functions required and b) adding member functions on SCEVExpander
that automatically take the SCEVExpander mode into account. We can
use the latter variant nearly everywhere, and thus make sure that
there is no chance of CanonicalMode mismatch.
Fixes https://github.com/llvm/llvm-project/issues/50506.
Differential Revision: https://reviews.llvm.org/D129630
After replacing a loop phi with the preheader value, it's usually
possible to simplify some of the using instructions, so do that as
part of replaceLoopPHINodesWithPreheaderValues().
Doing this as part of IndVars is valuable, because it may make GEPs
in the loop have constant offsets and allow the following SROA run
to succeed (as demonstrated in the PhaseOrdering test).
Differential Revision: https://reviews.llvm.org/D129293
Currently we only call replaceLoopPHINodesWithPreheaderValues() if
optimizeLoopExits() replaces the exit with an unconditional exit.
However, it is very common that this already happens as part of
eliminateIVComparison(), in which case we're leaving behind the
dead header phi.
Tweak the early bailout for already-constant exits to also call
replaceLoopPHINodesWithPreheaderValues().
Differential Revision: https://reviews.llvm.org/D129214
