In one case, we were handling out of bounds, but not undef indices. In the other, we were handling undef (with the comment making the analogy to out of bounds), but not out of bounds. Be consistent and treat both undef and constant out of bounds indices as producing undefined results.
As a side effect, this also protects instcombine from having to handle large constant indices as we always simplify first.
llvm-svn: 321575
This reverts r321138. It seems there are still underlying issues with
memdep. PR35519 seems to still be present if debug info is enabled. We
end up losing a memcpy. Somehow during store to memset merging, we
insert the memset after the memcpy or fail to update the memdep analysis
to account for the newly inserted memset of a pair.
Reduced test case:
#include <assert.h>
#include <stdio.h>
#include <string>
#include <utility>
#include <vector>
void do_push_back(
std::vector<std::pair<std::string, std::vector<std::string>>>* crls) {
crls->push_back(std::make_pair(std::string(), std::vector<std::string>()));
}
int __attribute__((optnone)) main() {
// Put some data in the vector and then remove it so we take the push_back
// fast path.
std::vector<std::pair<std::string, std::vector<std::string>>> crl_set;
crl_set.push_back({"asdf", {}});
crl_set.pop_back();
printf("first word in vector storage: %p\n", *(void**)crl_set.data());
// Do the push_back which may fail to initialize the data.
do_push_back(&crl_set);
auto* first = &crl_set.back().first;
printf("first word in vector storage (should be zero): %p\n",
*(void**)crl_set.data());
assert(first->empty());
puts("ok");
}
Compile with libc++, enable optimizations, and enable debug info:
$ clang++ -stdlib=libc++ -g -O2 t.cpp -o t.exe -Wl,-rpath=llvm/build/lib
This program will assert with this change.
llvm-svn: 321510
Summary:
When using byval, the data is effectively copied as part of the call
anyway, so we aren't actually passing the pointer and thus there is no
reason to issue a warning.
Reviewers: rnk
Reviewed By: rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40118
llvm-svn: 321478
InsertBinop tries to find an appropriate instruction instead of
creating a new instruction. When it checks whether instruction is
the same as we need to create it ignores nuw/nsw/exact flags.
It leads to invalid behavior when poison instruction can be used
when it was not expected. Specifically, for example Expander
expands the SCEV built for instruction
%a = add i32 %v, 1
It is possible that InsertBinop can find an instruction
% b = add nuw nsw i32 %v, 1
and will use it instead of version w/o nuw nsw.
It is incorrect.
The patch conservatively ignores all instructions with any of
poison flags installed.
Reviewers: sanjoy, mkazantsev, sebpop, jbhateja
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41576
llvm-svn: 321475
This is fix for the crash caused by ScalarEvolution::getTruncateExpr.
It expects that if it checked the condition that SCEV is not in UniqueSCEVs cache in
the beginning that it will not be there inside this method.
However during recursion and transformation/simplification for sub expression,
it is possible that these modifications will end up with the same SCEV as we started from.
So we must always check whether SCEV is in cache and do not insert item if it is already there.
Reviewers: sanjoy, mkazantsev, craig.topper
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41380
llvm-svn: 321472
This is a preliminary step for the patch discussed in D41136 (and denoted here with the FIXME comment).
When we match an FP min/max that is cast to integer, any intermediate difference between +0.0 or -0.0
should be muted in the result by the conversion (either fptosi or fptoui) of the result. Thus, we can
enable 'nsz' for the purpose of matching fmin/fmax.
Note that there's probably room to generalize this more, possibly by fixing the current calls to the
weak version of isKnownNonZero() in matchSelectPattern() to the more powerful recursive version.
Differential Revision: https://reviews.llvm.org/D41333
llvm-svn: 321456
Summary:
Make MemorySSA allow reordering of two loads that may alias, when one is volatile.
This makes MemorySSA less conservative and behaving the same as the AliasSetTracker.
For more context, see D16875.
LLVM language reference: "The optimizers must not change the number of volatile operations or change their order of execution relative to other volatile operations. The optimizers may change the order of volatile operations relative to non-volatile operations. This is not Java’s “volatile” and has no cross-thread synchronization behavior."
Reviewers: george.burgess.iv, dberlin
Subscribers: sanjoy, reames, hfinkel, llvm-commits, Prazek
Differential Revision: https://reviews.llvm.org/D41525
llvm-svn: 321382
If after if-conversion, most of the instructions in this new BB construct a long and slow dependence chain, it may be slower than cmp/branch, even if the branch has a high miss rate, because the control dependence is transformed into data dependence, and control dependence can be speculated, and thus, the second part can execute in parallel with the first part on modern OOO processor.
This patch checks for the long dependence chain, and give up if-conversion if find one.
Differential Revision: https://reviews.llvm.org/D39352
llvm-svn: 321377
Currently, inline cost model considers a binary operator as free only if both
its operands are constants. Some simple cases are missing such as a + 0, a - a,
etc. This patch modifies visitBinaryOperator() to call SimplifyBinOp() without
going through simplifyInstruction() to get rid of the constant restriction.
Thus, visitAnd() and visitOr() are not needed.
Differential Revision: https://reviews.llvm.org/D41494
llvm-svn: 321366
The penalty is currently getting applied in a bunch of places where it
doesn't make sense, like bitcasts (which are free) and calls (which
were getting the call penalty applied twice). Instead, just apply the
penalty to binary operators and floating-point casts.
While I'm here, also fix getFPOpCost() to do the right thing in more
cases, so we don't have to dig into function attributes.
Differential Revision: https://reviews.llvm.org/D41522
llvm-svn: 321332
Summary:
This replaces calls to getEntryCount().hasValue() with hasProfileData
that does the same thing. This refactoring is useful to do before adding
synthetic function entry counts but also a useful cleanup IMO even
otherwise. I have used hasProfileData instead of hasRealProfileData as
David had earlier suggested since I think profile implies "real" and I
use the phrase "synthetic entry count" and not "synthetic profile count"
but I am fine calling it hasRealProfileData if you prefer.
Reviewers: davidxl, silvas
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41461
llvm-svn: 321331
Summary:
Add an additional bit to ModRefInfo, ModRefInfo::Must, to be cleared for known must aliases.
Shift existing Mod/Ref/ModRef values to include an additional most
significant bit. Update wrappers that modify ModRefInfo values to
reflect the change.
Notes:
* ModRefInfo::Must is almost entirely cleared in the AAResults methods, the remaining changes are trying to preserve it.
* Only some small changes to make custom AA passes set ModRefInfo::Must (BasicAA).
* GlobalsModRef already declares a bit, who's meaning overlaps with the most significant bit in ModRefInfo (MayReadAnyGlobal). No changes to shift the value of MayReadAnyGlobal (see AlignedMap). FunctionInfo.getModRef() ajusts most significant bit so correctness is preserved, but the Must info is lost.
* There are cases where the ModRefInfo::Must is not set, e.g. 2 calls that only read will return ModRefInfo::NoModRef, though they may read from exactly the same location.
Reviewers: dberlin, hfinkel, george.burgess.iv
Subscribers: llvm-commits, sanjoy
Differential Revision: https://reviews.llvm.org/D38862
llvm-svn: 321309
Summary:
The function section prefix for PGO based layout (e.g. hot/unlikely)
should look at the hotness of all blocks not just the entry BB.
A function with a cold entry but a very hot loop should be placed in the
hot section, for example, so that it is located close to other hot
functions it may call. For SamplePGO it was already looking at the
branch weights on calls, and I made that code conditional on whether
this is SamplePGO since it was essentially a noop for instrumentation
PGO anyway.
Reviewers: davidxl
Subscribers: eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D41395
llvm-svn: 321197
This teaches memcpyopt to make a non-local memdep query when a local query
indicates that the dependency is non-local. This notably allows it to
eliminate many more llvm.memcpy calls in common Rust code, often by 20-30%.
This is r319482 and r319483, along with fixes for PR35519: fix the
optimization that merges stores into memsets to preserve cached memdep
info, and fix memdep's non-local caching strategy to not assume that larger
queries are always more conservative than smaller ones.
Fixes PR28958 and PR35519.
Differential Revision: https://reviews.llvm.org/D40802
llvm-svn: 321138
There are cases when two tags with different base types denote
accesses to the same direct or indirect member of a structure
type. Currently, merging of such tags results in a tag that
represents an access to an object that has the type of that
member. This patch changes this so that if one of the accesses
encloses the other, then the generic tag is the one of the
enclosed access.
Differential Revision: https://reviews.llvm.org/D39557
llvm-svn: 321019
Enhance LVI to analyze the ‘ashr’ binary operation. This leverages the infrastructure in ConstantRange for the ashr operation.
Patch by Surya Kumari Jangala!
Differential Revision: https://reviews.llvm.org/D40886
llvm-svn: 320983
When unsafe algerbra is allowed calls to cabs(r) can be replaced by:
sqrt(creal(r)*creal(r) + cimag(r)*cimag(r))
Patch by Paul Walker, thanks!
Differential Revision: https://reviews.llvm.org/D40069
llvm-svn: 320901
SROA analysis of InlineCost can figure out that some stores can be removed
after inlining and then the repeated loads clobbered by these stores are also
free. This patch finds these clobbered loads and adjust the inline cost
accordingly.
Differential Revision: https://reviews.llvm.org/D33946
llvm-svn: 320814
We cannot move the insertion point to header if SCEV contains div/rem
operations due to they may go over check for zero denominator.
Reviewers: sanjoy, mkazantsev, sebpop
Reviewed By: sebpop
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D41229
llvm-svn: 320789
Most of the -Wsign-compare warnings are due to the fact that
enums are signed by default in the MS ABI, while the
tautological comparison warnings trigger on x86 builds where
sizeof(size_t) is 4 bytes, so N > numeric_limits<unsigned>::max()
is always false.
Differential Revision: https://reviews.llvm.org/D41256
llvm-svn: 320750
Summary:
The function is meant to recurse until it comes upon the
phi it's looking for. However, with the current condition,
it will recurse until it finds anything _but_ the phi.
The function will even fail for simple cases like:
%i = phi i32 [ %inc, %loop ], ...
...
%inc = add i32 %i, 1
because the base condition will not happen when the phi
is recursed to, and the recursion will end with a 'false'
result since the previous instruction is a phi.
Reviewers: sanjoy, atrick
Reviewed By: sanjoy
Subscribers: Ka-Ka, bjope, llvm-commits
Committing on behalf of: Bevin Hansson (bevinh)
Differential Revision: https://reviews.llvm.org/D40946
llvm-svn: 320700
This patch fix this FIXME in visitPHI()
FIXME: We should potentially be tracking values through phi nodes,
especially when they collapse to a single value due to deleted CFG edges
during inlining.
Differential Revision: https://reviews.llvm.org/D38594
llvm-svn: 320699
D30041 extended SCEVPredicateRewriter to improve handling of Phi nodes whose
update chain involves casts; PSCEV can now build an AddRecurrence for some
forms of such phi nodes, under the proper runtime overflow test. This means
that we can identify such phi nodes as an induction, and the loop-vectorizer
can now vectorize such inductions, however inefficiently. The vectorizer
doesn't know that it can ignore the casts, and so it vectorizes them.
This patch records the casts in the InductionDescriptor, so that they could
be marked to be ignored for cost calculation (we use VecValuesToIgnore for
that) and ignored for vectorization/widening/scalarization (i.e. treated as
TriviallyDead).
In addition to marking all these casts to be ignored, we also need to make
sure that each cast is mapped to the right vector value in the vector loop body
(be it a widened, vectorized, or scalarized induction). So whenever an
induction phi is mapped to a vector value (during vectorization/widening/
scalarization), we also map the respective cast instruction (if exists) to that
vector value. (If the phi-update sequence of an induction involves more than one
cast, then the above mapping to vector value is relevant only for the last cast
of the sequence as we allow only the "last cast" to be used outside the
induction update chain itself).
This is the last step in addressing PR30654.
llvm-svn: 320672
Summary:
This patch tries to vectorize loads of consecutive memory accesses, accessed
in non-consecutive or jumbled way. An earlier attempt was made with patch D26905
which was reverted back due to some basic issue with representing the 'use mask' of
jumbled accesses.
This patch fixes the mask representation by recording the 'use mask' in the usertree entry.
Change-Id: I9fe7f5045f065d84c126fa307ef6ebe0787296df
Reviewers: mkuper, loladiro, Ayal, zvi, danielcdh
Reviewed By: Ayal
Subscribers: mgrang, dcaballe, hans, mzolotukhin
Differential Revision: https://reviews.llvm.org/D36130
llvm-svn: 320548
CreateAddRecFromPHIWithCastsImpl() adds an IncrementNUSW overflow predicate
which allows the PSCEV rewriter to rewrite this scev expression:
(zext i8 {0, + , (trunc i32 step to i8)} to i32)
into
{0, +, (sext i8 (trunc i32 step to i8) to i32)}
But then it adds the wrong Equal predicate:
%step == (zext i8 (trunc i32 %step to i8) to i32).
instead of:
%step == (sext i8 (trunc i32 %step to i8) to i32)
This is fixed here.
Differential Revision: https://reviews.llvm.org/D40641
llvm-svn: 320298
When the lowest bits of the operands to an integer multiply are known, the low bits of the result are deducible.
Code to deduce known-zero bottom bits already existed, but this change improves on that by deducing known-ones.
Patch by: Pedro Ferreira
Reviewers: craig.topper, sanjoy, efriedma
Differential Revision: https://reviews.llvm.org/D34029
llvm-svn: 320269
Summary:
This is LLVM instrumentation for the new HWASan tool. It is basically
a stripped down copy of ASan at this point, w/o stack or global
support. Instrumenation adds a global constructor + runtime callbacks
for every load and store.
HWASan comes with its own IR attribute.
A brief design document can be found in
clang/docs/HardwareAssistedAddressSanitizerDesign.rst (submitted earlier).
Reviewers: kcc, pcc, alekseyshl
Subscribers: srhines, mehdi_amini, mgorny, javed.absar, eraman, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D40932
llvm-svn: 320217
Causes unexpected memory issue with New PM this time.
The new PM invalidates BPI but not BFI, leaving the
reference to BPI from BFI invalid.
Abandon this patch. There is a more general solution
which also handles runtime infinite loop (but not statically).
llvm-svn: 320180
In this method, we invoke `SimplifyICmpOperands` which takes the `Cond` predicate
by reference and may change it along with `LHS` and `RHS` SCEVs. But then we invoke
`computeShiftCompareExitLimit` with Values from which the SCEVs have been derived,
these Values have not been modified while `Cond` could be.
One of possible outcomes of this is that we may falsely prove that an infinite loop ends
within some finite number of iterations.
In this patch, we save the original `Cond` and pass it along with original operands.
This logic may be removed in future once `computeShiftCompareExitLimit` works
with SCEVs instead of value operands.
Reviewed By: sanjoy
Differential Revision: https://reviews.llvm.org/D40953
llvm-svn: 320142
