This change makes the split between the "exact" backedge taken count
and the "maximum" backedge taken count a bit more obvious. Both of
these are upper bounds on the number of times the loop header
executes (since SCEV does not account for most kinds of abnormal
control flow), but the latter is guaranteed to be a constant.
There were a few places where the max backedge taken count *was* a
non-constant; I've changed those to compute constants instead.
At this point, I'm not sure if the constant max backedge count can be
computed by calling `getUnsignedRange(Exact).getUnsignedMax()` without
losing precision. If it can, we can simplify even further by making
`getMaxBackedgeTakenCount` a thin wrapper around
`getBackedgeTakenCount` and `getUnsignedRange`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303497 91177308-0d34-0410-b5e6-96231b3b80d8
Fixed "most platform" to read "most platforms", and changed "are not
using the same" to "use different" as a drive-by.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303487 91177308-0d34-0410-b5e6-96231b3b80d8
In the case where we have an operand defined by a lod of the
same memory location. Historically this was a VariableExpression
because we wanted to make sure they ended up in the same class,
but if we create the right expression, they end up in the same
class anyway.
Fixes PR32897. Thanks to Dan for the detailed discussion and the
fix suggestion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303475 91177308-0d34-0410-b5e6-96231b3b80d8
This was here because we don't want to switch leaders too much,
in order to avoid fixpoint(ing) issue, but it's not sure if it
matters in practice.
A first step towards fixing PR32897.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303473 91177308-0d34-0410-b5e6-96231b3b80d8
Refactor the strlen optimization code to work for both strlen and wcslen.
This especially helps with programs in the wild where people pass
L"string"s to const std::wstring& function parameters and the wstring
constructor gets inlined.
This also fixes a lingerind API problem/bug in getConstantStringInfo()
where zeroinitializers would always give you an empty string (without a
length) back regardless of the actual length of the initializer which
did not work well in the TrimAtNul==false causing the PR mentioned
below.
Note that the fixed getConstantStringInfo() needed fixes to SelectionDAG
memcpy lowering and may lead to some cases for out-of-bounds
zeroinitializer accesses not getting optimized anymore. So some code
with UB may produce out of bound memory reads now instead of just
producing zeros.
The refactoring "accidentally" fixes http://llvm.org/PR32124
Differential Revision: https://reviews.llvm.org/D32839
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303461 91177308-0d34-0410-b5e6-96231b3b80d8
getParamAlignment expects an argument number, not an AttributeList
index.
Johan Englan, who works on LDC, found this bug and told me about it off
list.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303458 91177308-0d34-0410-b5e6-96231b3b80d8
This is a complicated bug involving two issues:
1. What do we do with phi nodes when we prove all arguments are not
live?
2. When is it safe to use value leaders to determine if we can ignore
an argumnet?
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303453 91177308-0d34-0410-b5e6-96231b3b80d8
This was originally reverted because it was a breaking a bunch
of bots and the breakage was not surfacing on Windows. After much
head-scratching this was ultimately traced back to a bug in the
lit test runner related to its pipe handling. Now that the bug
in lit is fixed, Windows correctly reports these test failures,
and as such I have finally (hopefully) fixed all of them in this
patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303446 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
NewGVN: Handle equivalence between phi of ops and op of phis.
This makes our GVN mostly-complete. It would be complete, modulo some
deliberate choices we make. This means it detects roughly all herband
equivalences in polynomial time, including cases notoriously hard for
other GVN's to detect. It also detects a very large swath of the
cases we currently rely on instcombine to detect that involve folding
upwards through phis.
Fixes PR 31125, 31463, PR 31868
Reviewers: davide
Subscribers: Prazek, llvm-commits
Differential Revision: https://reviews.llvm.org/D32151
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303444 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
While this makes some case better and some case worse - so it's unclear if it is a worthy combine just by itself - this is a useful canonicalisation.
As per discussion in D32756 .
Reviewers: jyknight, nemanjai, mkuper, spatel, RKSimon, zvi, bkramer
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32916
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303441 91177308-0d34-0410-b5e6-96231b3b80d8
This seems to have been present since the beginning of time,
which is quite surprising. The symptom was this: Suppose you
have a test with a run line that looks like this:
RUN: foo | FileCheck %s
foo prints some output and then due to a bug in the program it
asserts. On Windows this results in the program returning a
negative exit code. But if enough output had been printed
already by the tool so that the FileCheck match would succeed
then FileCheck would return 0, and because of bad logic in
lit this 0 return value would overwrite the failed return
value from previous items in the pipeline. This only happened
with negative exit codes.
The most sensible behavior is to just take whatever the first
exit code is. There is no logical ordering defined on exit
codes, so comparing with < and > does not make a lot of sense.
Instead, as soon as we find the first non-successful return
value, that should be the result of the entire expression.
This fixes the issue, as now tests which fail on non-Windows
platforms also fail for me on Windows as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303440 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This NFC simply refactors the return value of LoopIdiomRecognize::isLegalStore() from bool to an enumeration, and
removes the return-through-parameter mechanism that the function was using. This function is constructed such that it will
only ever recognize a single store idiom (memset, memset_pattern, or memcpy), and never a combination of these. As such it
makes much more sense for the return value to be the single idiom that the store matches, rather than
having a separate argument-return for each idiom -- it's cleaner, and makes it clearer that
only a single idiom can be matched.
Patch by Daniel Neilson!
Reviewers: anna, sanjoy, davide, haicheng
Reviewed By: anna, haicheng
Subscribers: haicheng, mzolotukhin, llvm-commits
Differential Revision: https://reviews.llvm.org/D33359
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303434 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch adds udiv/sdiv/urem/srem/udivrem/sdivrem methods that can divide by a uint64_t. This makes division consistent with all the other arithmetic operations.
This modifies the interface of the divide helper method to work on raw arrays instead of APInts. This way we can pass the uint64_t in for the RHS without wrapping it in an APInt. This required moving all the Quotient and Remainder allocation handling up to the callers. For udiv/urem this was as simple as just creating the Quotient/Remainder with the right size when they were declared. For udivrem we have to rely on reallocate not changing the contents of the variable LHS or RHS is aliased with the Quotient or Remainder APInts. We also have to zero the upper bits of Remainder and Quotient that divide doesn't write to if lhsWords/rhsWords is smaller than the width.
I've update the toString method to use the new udivrem.
Reviewers: hans, dblaikie, RKSimon
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33310
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303431 91177308-0d34-0410-b5e6-96231b3b80d8
