The get{Return,Unwind,Unreachable}Block functions in
UnifyFunctionExitNodes have not been used for many years,
so just remove them.
Reviewed By: bjope
Differential Revision: https://reviews.llvm.org/D87078
To enable the cost of constants, the helper function has been
reorganised:
- A struct has been introduced to hold SCEV operand information so
that we know the user of the operand, as well as the operand index.
The Worklist now uses instead instead of a bare SCEV.
- The costing of each SCEV, and collection of its operands, is now
performed in a helper function.
Differential Revision: https://reviews.llvm.org/D86050
Modify FoldBranchToCommonDest to consider the cost of inserting
instructions when attempting to combine predicates to fold blocks.
The threshold can be controlled via a new option:
-simplifycfg-branch-fold-threshold which defaults to '2' to allow
the insertion of a not and another logical operator.
Differential Revision: https://reviews.llvm.org/D86526
When a switch case is folded into default's case, that's an IR change that
should be reported, update ConstantFoldTerminator accordingly.
Differential Revision: https://reviews.llvm.org/D87142
EarlyCSE has a mode to verify the invariant that hash equality equals
key equality, but EliminateDuplicatePHINodes() doesn't.
I've verified that this would have caught the stage2-stage3 mismatches
5ec2b757cc revert has fixed,
that were introduced last time in 3e69871ab5.
This patch changes ElementCount so that the Min and Scalable
members are now private and can only be accessed via the get
functions getKnownMinValue() and isScalable(). In addition I've
added some other member functions for more commonly used operations.
Hopefully this makes the class more useful and will reduce the
need for calling getKnownMinValue().
Differential Revision: https://reviews.llvm.org/D86065
strspn, strncmp, strcspn, strcasecmp, strncasecmp, memcmp, memchr,
memrchr, memcpy, memmove, memcpy, mempcpy, strchr, strrchr, bcmp
should all only access memory through their arguments.
I broke out strcoll, strcasecmp, strncasecmp because the result
depends on the locale, which might get accessed through memory.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D86724
Currently we bail out early for strlen calls with a GEP operand, if none
of the GEP specific optimizations fire. But there could be later
optimizations that still apply, which we currently miss out on.
An example is that we do not apply the following optimization
strlen(x) == 0 --> *x == 0
Unless I am missing something, there seems to be no reason for bailing
out early there.
Fixes PR47149.
Reviewed By: lebedev.ri, xbolva00
Differential Revision: https://reviews.llvm.org/D85886
When trying to enable -debug-info-kind=constructor there was an assert
that occurs during debug info cloning ("mismatched subprogram between
llvm.dbg.value variable and !dbg attachment").
It appears that during llvm::CloneFunctionInto, a DISubprogram could be
duplicated when MapMetadata is called, and then added to the MD map again
when DIFinder gets a list of subprograms. This results in two different
versions of the DISubprogram.
This patch switches the order so that the DIFinder subprograms are
added before MapMetadata is called.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46784
Differential Revision: https://reviews.llvm.org/D86185
Recommit the patch after fixing an issue reported caused by the fact
that re-used values are also added to InsertedValues.
Additional tests have been added in 88818491b9
This reverts the revert commit 38884641f2.
Before we speculatively execute a basic block, query the cost of
inserting the necessary select instructions against the phi folding
threshold. For non-trivial insertions, a more accurate decision can
probably be made during machine if-conversion. With minsize we query
the CodeSize cost, otherwise we use SizeAndLatency.
Differential Revision: https://reviews.llvm.org/D82438
This reverts commit 6dbf0cfcf7.
That commit caused failed assertions, e.g. like this:
$ cat sprintf-strcpy.c
char *ptr; void func(void) { ptr += sprintf(ptr, "%s", ""); }
$ clang -c sprintf-strcpy.c -O2 -target x86_64-linux-gnu
clang: ../lib/IR/Value.cpp:473: void llvm::Value::doRAUW(llvm::Value*,
llvm::Value::ReplaceMetadataUses): Assertion `New->getType() ==
getType() && "replaceAllUses of value with new value of different
type!"' failed.
Transformation creates big strings for big C values, so bail out for C > 128.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D86004
When removing instructions from unreachable blocks, and only debug info
intrinsics were removed, InstCombine could incorrectly return a false
Modified status.
This is fixed by making removeAllNonTerminatorAndEHPadInstructions()
also return how many debug info intrinsics that were removed, and take
that into account.
This was caught using the check introduced by D80916.
Reviewed By: majnemer
Differential Revision: https://reviews.llvm.org/D85839
SCEVExpander already tracks which instructions have been inserted n
InsertedValues/InsertedPostIncValues. This patch adds an additional
vector to collect the instructions in insertion order. This can then be
used to remove exactly the instructions inserted by the expander.
This replaces ExpandedValuesCleaner, which in some cases might remove
values not inserted by the expander (e.g. if a value was dead before
insertion and is then used during expansion).
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D84327
This patch adds noundef to return value and arguments of standard I/O functions.
With this patch, passing undef or poison to the functions becomes undefined
behavior in LLVM IR. Since undef/poison is lowered from operations having UB in C/C++,
passing undef to them was already UB in source.
With this patch, the functions cannot return undef or poison anymore as well.
According to C17 standard, ungetc/ungetwc/fgetpos/ftell can generate unspecified
value; 3.19.3 says unspecified value is a valid value of the relevant type,
and using unspecified value is unspecified behavior, which is not UB, so it
cannot be undef (using undef is UB when e.g. it is used at branch condition).
— The value of the file position indicator after a successful call to the ungetc function for a text stream, or the ungetwc function for any stream, until all pushed-back characters are read or discarded (7.21.7.10, 7.29.3.10).
— The details of the value stored by the fgetpos function (7.21.9.1).
— The details of the value returned by the ftell function for a text stream (7.21.9.4).
In the long run, most of the functions listed in BuildLibCalls should have noundefs; to remove redundant diffs which will anyway disappear in the future, I added noundef to a few more non-I/O functions as well.
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D85345
Currently the SCEVExpander tries to re-use existing casts, even if they
are not exactly at the insertion point it was asked to create the cast.
To do so in some case, it creates a new cast at the insertion point and
updates all users to use the new cast.
This behavior is problematic, because it changes the IR outside of the
instructions created during the expansion. Therefore we cannot
completely undo all changes made during expansion.
This re-use should be only an extra optimization, so only using the new
cast in the expanded instructions should not be a correctness issue.
There are many cases equivalent instructions are created during
expansion.
This patch also adjusts findInsertPointAfter to skip instructions
inserted during expansion. This enables re-using existing casts without
the renaming any uses, by picking a better insertion point.
Reviewed By: efriedma, lebedev.ri
Differential Revision: https://reviews.llvm.org/D84399
SimplifyCFG has two main folds for resumes - one when resume is directly
using the landingpad, and the other one where resume is using a PHI node.
While for the first case, we were already correctly ignoring all the
PHI nodes, and both the debug info intrinsics and lifetime intrinsics,
in the PHI-based-one, we weren't ignoring PHI's in the resume block,
and weren't ignoring lifetime intrinsics. That is clearly a bug.
On RawSpeed library, this results in +9.34% (+81) more invoke->call folds,
-0.19% (-39) landing pads, -0.24% (-81) invoke instructions
but +51 call instructions and -132 basic blocks.
Though, the run-time performance impact appears to be within the noise.
formLCSSAForInstructions is used by SCEVExpander, which tracks all
inserted instructions including LCSSA phis using asserting value
handles. This means cleanup needs to happen in the caller.
Extend formLCSSAForInstructions to take an optional pointer to a
vector. If this argument is non-nullptr, instead of directly deleting
the phis, add them to the vector, so the caller can process them.
This should address various PPC buildbot failures, including
http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/40567
Use IRBuilder instead PHINode::Create. This should not impact the
generated code, but IRBuilder provides a way to register callbacks for
inserted instructions, which is convenient for some users.
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D85037
querying getSCEV() for incomplete phis leads to wrong cache value in `ExprToIVMap`,
because incomplete phis may be simplified to same value before get SCEV expression.
Reviewed By: lebedev.ri, mkazantsev
Differential Revision: https://reviews.llvm.org/D77560
Summary: This patch separates the Loop Peeling Utilities from Loop Unrolling.
The reason for this change is that Loop Peeling is no longer only being used by
loop unrolling; Patch D82927 introduces loop peeling with fusion, such that
loops can be modified to have to same trip count, making them legal to be
peeled.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D83056
This reverts the revert commit dc28675768.
It includes a fix for Polly, which uses SCEVExpander on IR that is not
in LCSSA form. Set PreserveLCSSA = false in that case, to ensure we do
not introduce LCSSA phis where there were none before.
This reverts commit 99166fd4fb, because it
breaks the polly builders.
polly/test/Isl/CodeGen/invariant_load_escaping_second_scop.ll fails
because a apparently unnecessary LCSSA phi node is introduced.
Make the bots green again, while I take a closer look.
This patch teaches SCEVExpander to directly preserve LCSSA.
As it is currently, SCEV does not look through PHI nodes in loops,
as it might break LCSSA form. Once SCEVExpander can preserve
LCSSA form, it should be safe for SCEV to look through PHIs.
To preserve LCSSA form, this patch uses formLCSSAForInstructions
on operands of newly created instructions, if the definition is inside
a different loop than the new instruction.
The final value we return from expandCodeFor may also need LCSSA
phis, depending on the insert point. As no user for it exists there yet,
create a temporary instruction at the insert point, which can be passed
to formLCSSAForInstructions. This temporary instruction is removed
after LCSSA construction.
Reviewed By: mkazantsev
Differential Revision: https://reviews.llvm.org/D71538
Currently, getCastInstrCost has limited information about the cast it's
rating, often just the opcode and types. Sometimes there is a context
instruction as well, but it isn't trustworthy: for instance, when the
vectorizer is rating a plan, it calls getCastInstrCost with the old
instructions when, in fact, it's trying to evaluate the cost of the
instruction post-vectorization. Thus, the current system can get the
cost of certain casts incorrect as the correct cost can vary greatly
based on the context in which it's used.
For example, if the vectorizer queries getCastInstrCost to evaluate the
cost of a sext(load) with tail predication enabled, getCastInstrCost
will think it's free most of the time, but it's not always free. On ARM
MVE, a VLD2 group cannot be extended like a normal VLDR can. Similar
situations can come up with how masked loads can be extended when being
split.
To fix that, this path adds a new parameter to getCastInstrCost to give
it a hint about the context of the cast. It adds a CastContextHint enum
which contains the type of the load/store being created by the
vectorizer - one for each of the types it can produce.
Original patch by Pierre van Houtryve
Differential Revision: https://reviews.llvm.org/D79162
We can happily turn function definitions into declarations,
thus obscuring their argument from being elided by this pass.
I don't believe there is a good reason to just ignore declarations.
likely even proper llvm intrinsics ones,
at worst the input becomes uninteresting.
The other question here is that all these transforms are all-or-nothing.
In some cases, should we be treating each use separately?
The main blocker here seemed to be that llvm::CloneFunctionInto()
does `&OldFunc->front()`, which inserts a nullptr into a densemap,
which is not happy about it and asserts.
David Stenberg