Verifications of dominator tree and loop info are expensive operations
so they are disabled by default. They can be enabled by command line
options -verify-dom-info and -verify-loop-info. These options however
enable checks only in files Dominators.cpp and LoopInfo.cpp. If some
transformation changes dominaror tree and/or loop info, it would be
convenient to place similar checks to the files implementing the
transformation.
This change makes corresponding flags global, so they can be used in
any file to optionally turn verification on.
llvm-svn: 292889
Summary:
The LibFunc::Func enum holds enumerators named for libc functions.
Unfortunately, there are real situations, including libc implementations, where
function names are actually macros (musl uses "#define fopen64 fopen", for
example; any other transitively visible macro would have similar effects).
Strictly speaking, a conforming C++ Standard Library should provide any such
macros as functions instead (via <cstdio>). However, there are some "library"
functions which are not part of the standard, and thus not subject to this
rule (fopen64, for example). So, in order to be both portable and consistent,
the enum should not use the bare function names.
The old enum naming used a namespace LibFunc and an enum Func, with bare
enumerators. This patch changes LibFunc to be an enum with enumerators prefixed
with "LibFFunc_". (Unfortunately, a scoped enum is not sufficient to override
macros.)
There are additional changes required in clang.
Reviewers: rsmith
Subscribers: mehdi_amini, mzolotukhin, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D28476
llvm-svn: 292848
become unavailable.
The AssumptionCache is now immutable but it still needs to respond to
DomTree invalidation if it ended up caching one.
This lets us remove one of the explicit invalidates of LVI but the
other one continues to avoid hitting a latent bug.
llvm-svn: 292769
This is similar to what the caller (matchSelectPattern()) does. In all
cases where we succeed in matching a min/max pattern, the values in
that pattern will be the values of the 'select', so hoist that and
remove a bunch of duplicated code.
llvm-svn: 292725
Summary:
Currently we return undef, but we're in the process of changing the
LangRef so that llvm.sqrt behaves like the other math intrinsics,
matching the return value of the standard libcall but not setting errno.
This change is legal even without the LangRef change because currently
calling llvm.sqrt(x) where x is negative is spec'ed to be UB. But in
practice it's also safe because we're simply constant-folding fewer
inputs: Inputs >= -0 get constant-folded as before, but inputs < -0 now
aren't constant-folded, because ConstantFoldFP aborts if the host math
function raises an fp exception.
Reviewers: hfinkel, efriedma, sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28929
llvm-svn: 292692
This adds the following to the new PM based inliner in PGO mode:
* Use block frequency analysis to derive callsite's profile count and use
that to adjust thresholds of hot and cold callsites.
* Incrementally update the BFI of the caller after a callee gets inlined
into it. This incremental update is only within an invocation of the run
method - BFI is not preserved across calls to run.
Update the function entry count of the callee after inlining it into a
caller.
* I've tuned the thresholds for the hot and cold callsites using a hacked
up version of the old inliner that explicitly computes BFI on a set of
internal benchmarks and spec. Once the new PM based pipeline stabilizes
(IIRC Chandler mentioned there are known issues) I'll benchmark this
again and adjust the thresholds if required.
Inliner PGO support.
Differential revision: https://reviews.llvm.org/D28331
llvm-svn: 292666
This is the third attemp to recommit r292526.
The original summary:
Currently, a GEP is considered free only if its indices are all constant.
TTI::getGEPCost() can give target-specific more accurate analysis. TTI is
already used for the cost of many other instructions.
llvm-svn: 292633
This is the second attemp to recommit r292526.
The original summary:
Currently, a GEP is considered free only if its indices are all constant.
TTI::getGEPCost() can give target-specific more accurate analysis. TTI is
already used for the cost of many other instructions.
llvm-svn: 292616
This recommits r292526 which is reverted in r292529 after fixing the test case.
The original summary:
Currently, a GEP is considered free only if its indices are all constant.
TTI::getGEPCost() can give target-specific more accurate analysis. TTI is
already used for the cost of many other instructions.
llvm-svn: 292570
loops in a function.
These are relatively confusing to talk about and compute correctly so it
seems really good to write down their implementation in one place. I've
replaced one place we needed this in the loop PM infrastructure and
I have another place in a pending patch that wants it.
We can't quite use this for the core loop PM walk because there we're
sometimes working on a sub-forest.
I'll add the expected unittests before committing this but wanted to
make sure folks were happy with these names / comments.
Credit goes to Richard Smith for the idea for naming the order where siblings
are in reverse program order but the tree traversal remains preorder.
Differential Revision: https://reviews.llvm.org/D28932
llvm-svn: 292569
Summary:
Fence instructions are currently marked as `ModRef` for all memory locations.
We can improve this for constant memory locations (such as constant globals),
since fence instructions cannot modify these locations.
This helps us to forward constant loads across fences (added test case in GVN).
There were no changes in behaviour for similar test cases in early-cse and licm.
Reviewers: dberlin, sanjoy, reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D28914
llvm-svn: 292546
Currently, a GEP is considered free only if its indices are all constant.
TTI::getGEPCost() can give target-specific more accurate analysis. TTI is
already used for the cost of many other instructions.
Differential Revision: https://reviews.llvm.org/D28693
llvm-svn: 292526
The scaling is done with reference to the the new frequency of a reference block.
Differential Revision: https://reviews.llvm.org/D28535
llvm-svn: 292507
To avoid regressions, make ScalarEvolution::createSCEV a bit more
clever.
Also get rid of some useless code in ScalarEvolution::howFarToZero
which was hiding this bug.
No new testcase because it's impossible to actually expose this bug:
we don't have any in-tree users of getUDivExactExpr besides the two
functions I just mentioned, and they both dodged the problem. I'll
try to add some interesting users in a followup.
Differential Revision: https://reviews.llvm.org/D28587
llvm-svn: 292449
Before, it would print a sequence of:
*** IR Dump After Function Integration/Inlining ******
*** IR Dump After Function Integration/Inlining ******
*** IR Dump After Function Integration/Inlining ******
...
for every single function in the module.
llvm-svn: 292442
r292188 confused MSVC because of the combined lack of a default
case and return statement.
Move the unreachable outside of the NumLibFuncs case, to make it
obvious that all cases should be handled.
llvm_unreachable is __declspec(noreturn), so I'm assuming this
does appease MSVC.
llvm-svn: 292246
Also, add the corresponding match to the AssumptionCache's 'Affected Values' list.
Differential Revision: https://reviews.llvm.org/D28485
llvm-svn: 292239
This is another step towards unifying all LibFunc prototype checks.
This work started in r267758 (D19469); add the remaining checks.
Also add a unittest that checks each libfunc declared with a known-valid
and known-invalid prototype. New libfuncs added in the future are
required to have prototype checking in place; the known-valid test will
fail otherwise.
Differential Revision: https://reviews.llvm.org/D28030
llvm-svn: 292188
When transferring affected values in the cache from an old value, identified by
the value of the current callback, to the specified new value we might need to
insert a new entry into the DenseMap which constitutes the cache. Doing so
might delete the current callback object. Move the copying logic into a new
function, a member of the assumption cache itself, so that we don't run into UB
should the callback handle itself be removed mid-copy.
Differential Revision: https://reviews.llvm.org/D28749
llvm-svn: 292133
Summary:
Use getLoopLatch in place of isLoopSimplifyForm. we do not need
to know whether the loop has a preheader nor dedicated exits.
Reviewers: hfinkel, sanjoy, atrick, mkuper
Subscribers: mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D28724
llvm-svn: 292078
events.
This pass sometimes has a pointer to BlockFrequencyInfo so it needs
custom invalidation logic. It is also otherwise immutable so we can
reduce the number of invalidations that happen substantially.
llvm-svn: 292058
a function's CFG when that CFG is unchanged.
This allows transformation passes to simply claim they preserve the CFG
and analysis passes to check for the CFG being preserved to remove the
fanout of all analyses being listed in all passes.
I've gone through and removed or cleaned up as many of the comments
reminding us to do this as I could.
Differential Revision: https://reviews.llvm.org/D28627
llvm-svn: 292054
mark it as never invalidated in the new PM.
The old PM already required this to work, and after a discussion with
Hal this seems to really be the only sensible answer. The cache
gracefully degrades as the IR is mutated, and most things which do this
should already be incrementally updating the cache.
This gets rid of a bunch of logic preserving and testing the
invalidation of this analysis.
llvm-svn: 292039
This fallthrough if other cases are added between fabs and default
could cause fabs to fall to the next case resulting in a bug.
Better getting rid of it immediately just to be sure.
llvm-svn: 292003
extractProfTotalWeight checks if the profile type is sample profile, but
before that we have to ensure that summary is available. Also expanded
the unittest to test the case where there is no summar
Differential Revision: https://reviews.llvm.org/D28708
llvm-svn: 291982
- For a loop body with VERY complicated exit condition evaluation, constant
evolving may run out of stack on platforms such as Windows. Need to limit the
recursion depth.
Differential Revision: https://reviews.llvm.org/D28629
llvm-svn: 291927
Running tests with expensive checks enabled exhibits some problems with
verification of pass results.
First, the pass verification may require results of analysis that are not
available. For instance, verification of loop info requires results of dominator
tree analysis. A pass may be marked as conserving loop info but does not need to
be dependent on DominatorTreePass. When a pass manager tries to verify that loop
info is valid, it needs dominator tree, but corresponding analysis may be
already destroyed as no user of it remained.
Another case is a pass that is skipped. For instance, entities with linkage
available_externally do not need code generation and such passes are skipped for
them. In this case result verification must also be skipped.
To solve these problems this change introduces a special flag to the Pass
structure to mark passes that have valid results. If this flag is reset,
verifications dependent on the pass result are skipped.
Differential Revision: https://reviews.llvm.org/D27190
llvm-svn: 291882
* Add is{Hot|Cold}CallSite methods
* Fix a bug in isHotBB where it was looking for MD_prof on a return instruction
* Use MD_prof data only if sample profiling was used to collect profiles.
* Add an unit test to ProfileSummaryInfo
Differential Revision: https://reviews.llvm.org/D28584
llvm-svn: 291878
Summary:
Memory Dependence Analysis was limited to return only local dependencies
for invariant.group handling. Now it returns NonLocal when it finds it
and then by asking getNonLocalPointerDependency we get found dep.
Thanks to this we are able to devirtualize loops!
void indirect(A &a, int n) {
for (int i = 0 ; i < n; i++)
a.foo();
}
void test(int n) {
A a;
indirect(a);
}
After inlining a.foo() will be changed to direct call, even if foo and A::A()
is external (but only if vtable definition is be available).
Reviewers: nlewycky, dberlin, chandlerc, rsmith
Subscribers: mehdi_amini, davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D28137
llvm-svn: 291762
Refines max backedge-taken count if a loop like
"for (int i = 0; i != n; ++i) { /* body */ }" is rotated.
Differential Revision: https://reviews.llvm.org/D28536
llvm-svn: 291704
This is both easier to understand, and produces a tighter bound in certain
cases.
Differential Revision: https://reviews.llvm.org/D28393
llvm-svn: 291701
Here's my second try at making @llvm.assume processing more efficient. My
previous attempt, which leveraged operand bundles, r289755, didn't end up
working: it did make assume processing more efficient but eliminating the
assumption cache made ephemeral value computation too expensive. This is a
more-targeted change. We'll keep the assumption cache, but extend it to keep a
map of affected values (i.e. values about which an assumption might provide
some information) to the corresponding assumption intrinsics. This allows
ValueTracking and LVI to find assumptions relevant to the value being queried
without scanning all assumptions in the function. The fact that ValueTracking
started doing O(number of assumptions in the function) work, for every
known-bits query, has become prohibitively expensive in some cases.
As discussed during the review, this is a pragmatic fix that, longer term, will
likely be replaced by a more-principled solution (perhaps based on an extended
SSA form).
Differential Revision: https://reviews.llvm.org/D28459
llvm-svn: 291671
the latter to the Transforms library.
While the loop PM uses an analysis to form the IR units, the current
plan is to have the PM itself establish and enforce both loop simplified
form and LCSSA. This would be a layering violation in the analysis
library.
Fundamentally, the idea behind the loop PM is to *transform* loops in
addition to running passes over them, so it really seemed like the most
natural place to sink this was into the transforms library.
We can't just move *everything* because we also have loop analyses that
rely on a subset of the invariants. So this patch splits the the loop
infrastructure into the analysis management that has to be part of the
analysis library, and the transform-aware pass manager.
This also required splitting the loop analyses' printer passes out to
the transforms library, which makes sense to me as running these will
transform the code into LCSSA in theory.
I haven't split the unittest though because testing one component
without the other seems nearly intractable.
Differential Revision: https://reviews.llvm.org/D28452
llvm-svn: 291662
updated instructions:
pmulld, pmullw, pmulhw, mulsd, mulps, mulpd, divss, divps, divsd, divpd, addpd and subpd.
special optimization case which replaces pmulld with pmullw\pmulhw\pshuf seq.
In case if the real operands bitwidth <= 16.
Differential Revision: https://reviews.llvm.org/D28104
llvm-svn: 291657
arguments much like the CGSCC pass manager.
This is a major redesign following the pattern establish for the CGSCC layer to
support updates to the set of loops during the traversal of the loop nest and
to support invalidation of analyses.
An additional significant burden in the loop PM is that so many passes require
access to a large number of function analyses. Manually ensuring these are
cached, available, and preserved has been a long-standing burden in LLVM even
with the help of the automatic scheduling in the old pass manager. And it made
the new pass manager extremely unweildy. With this design, we can package the
common analyses up while in a function pass and make them immediately available
to all the loop passes. While in some cases this is unnecessary, I think the
simplicity afforded is worth it.
This does not (yet) address loop simplified form or LCSSA form, but those are
the next things on my radar and I have a clear plan for them.
While the patch is very large, most of it is either mechanically updating loop
passes to the new API or the new testing for the loop PM. The code for it is
reasonably compact.
I have not yet updated all of the loop passes to correctly leverage the update
mechanisms demonstrated in the unittests. I'll do that in follow-up patches
along with improved FileCheck tests for those passes that ensure things work in
more realistic scenarios. In many cases, there isn't much we can do with these
until the loop simplified form and LCSSA form are in place.
Differential Revision: https://reviews.llvm.org/D28292
llvm-svn: 291651