Added a type check in ScalarEvolution::computeSCEVAtScope to handle the case in which operands of an
AddRecExpr in the current scope are folded.
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SCEV may generate expressions composed of multiple pointers, which can
lead to invalid GEP expansion. Until we can teach SCEV to follow strict
pointer rules, make sure no bad GEPs creep into IR.
Fixes rdar://problem/9038671.
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properties.
Added the self-wrap flag for SCEV::AddRecExpr.
A slew of temporary FIXMEs indicate the intention of the no-self-wrap flag
without changing behavior in this revision.
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When ExactBECount is a constant, use it for MaxBECount.
When MaxBECount cannot be computed, replace it with ExactBECount.
Fixes PR9424.
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This fixes a FIXME in scev-aa.ll (allowing a new no-alias result) and
generally makes things more precise.
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unsigned overflow (e.g. "gep P, -1"), and while they can have
signed wrap in theoretical situations, modelling an AddRec as
not having signed wrap is going enough for any case we can
think of today. In the future if this isn't enough, we can
revisit this. Modeling them as having NUW isn't causing any
known problems either FWIW.
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doesn't return immediately after then the insert position in UniqueSCEVs will
be out of date. No test because this is a memory corruption issue. Fixes PR9051!
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by indvars through the scev expander.
trunc(add x, y) --> add(trunc x, y). Currently SCEV largely folds the other way
which is probably wrong, but preserved to minimize churn. Instcombine doesn't
do this fold either, demonstrating a missed optz'n opportunity on code doing
add+trunc+add.
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a + {b,+,stride} into {a+b,+,stride} (because a is LIV),
then the resultant AddRec is NUW/NSW if the client says it
is.
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void f(int* begin, int* end) { std::fill(begin, end, 0); }
which turns into a != exit expression where one pointer is
strided and (thanks to step #1) known to not overflow, and
the other is loop invariant.
The observation here is that, though the IV is strided by
4 in this case, that the IV *has* to become equal to the
end value. It cannot "miss" the end value by stepping over
it, because if it did, the strided IV expression would
eventually wrap around.
Handle this by turning A != B into "A-B != 0" where the A-B
part is known to be NUW.
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zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.
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preserves LCSSA form out of ScalarEvolution and into the LoopInfo
class. Use it to check that SimplifyInstruction simplifications
are not breaking LCSSA form. Fixes PR8622.
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Some of these maps may merge in the future, but for now it's convenient to have
a utility function for them.
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memoize the results. This improves compile time in code which highly complex
expressions which get queried many times.
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needs to be checked that this won't break LCSSA form.
Change the existing checking method to a more direct one:
rather than seeing if all predecessors belong to the loop,
check that the replacing value is either not in any loop or
is in a loop that contains the phi node.
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they may have ValuesAtScopes map entries referencing their outer loops.
This fixes a user-after-free reported in PR8471.
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