[PM] Port LoopAccessInfo analysis to new PM

It is implemented as a LoopAnalysis pass as
discussed and agreed upon.

llvm-svn: 274452

[SCEV] Improve the run-time checking of the NoWrap predicate

Summary:
This implements a new method of run-time checking the NoWrap
SCEV predicates, which should be easier to optimize and nicer
for t

[SCEV] Improve the run-time checking of the NoWrap predicate

Summary:
This implements a new method of run-time checking the NoWrap
SCEV predicates, which should be easier to optimize and nicer
for targets that don't correctly handle multiplication/addition
of large integer types (like i128).

If the AddRec is {a,+,b} and the backedge taken count is c,
the idea is to check that |b| * c doesn't have unsigned overflow,
and depending on the sign of b, that:

a + |b| * c >= a (b >= 0) or
a - |b| * c <= a (b <= 0)

where the comparisons above are signed or unsigned, depending on
the flag that we're checking.

The advantage of doing this is that we avoid extending to a larger
type and we avoid the multiplication of large types (multiplying
i128 can be expensive).

Reviewers: sanjoy

Subscribers: llvm-commits, mzolotukhin

Differential Revision: http://reviews.llvm.org/D19266

llvm-svn: 267389

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[SCEV][LAA] Add tests for SCEV expression transformations performed during LAA

Summary:
Add a print method to Predicated Scalar Evolution which prints all interesting
transformations done by PSE.

L

[SCEV][LAA] Add tests for SCEV expression transformations performed during LAA

Summary:
Add a print method to Predicated Scalar Evolution which prints all interesting
transformations done by PSE.

Loop Access Analysis will now print this as part of the analysis output.
We now use this to check the exact expression transformations that were done
by PSE in LAA.

The additional checking also acts as white-box testing for the getAsAddRec method.

Reviewers: anemet, sanjoy

Subscribers: sanjoy, mzolotukhin, llvm-commits

Differential Revision: http://reviews.llvm.org/D18792

llvm-svn: 266334

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[SCEV][LAA] Re-commit r260085 and r260086, this time with a fix for the memory
sanitizer issue. The PredicatedScalarEvolution's copy constructor
wasn't copying the Generation value, and was leaving i

[SCEV][LAA] Re-commit r260085 and r260086, this time with a fix for the memory
sanitizer issue. The PredicatedScalarEvolution's copy constructor
wasn't copying the Generation value, and was leaving it un-initialized.

Original commit message:

[SCEV][LAA] Add no wrap SCEV predicates and use use them to improve strided pointer detection

Summary:
This change adds no wrap SCEV predicates with:
- support for runtime checking
- support for expression rewriting:
(sext ({x,+,y}) -> {sext(x),+,sext(y)}
(zext ({x,+,y}) -> {zext(x),+,sext(y)}

Note that we are sign extending the increment of the SCEV, even for
the zext case. This is needed to cover the fairly common case where y would
be a (small) negative integer. In order to do this, this change adds two new
flags: nusw and nssw that are applicable to AddRecExprs and permit the
transformations above.

We also change isStridedPtr in LAA to be able to make use of
these predicates. With this feature we should now always be able to
work around overflow issues in the dependence analysis.

Reviewers: mzolotukhin, sanjoy, anemet

Subscribers: mzolotukhin, sanjoy, llvm-commits, rengolin, jmolloy, hfinkel

Differential Revision: http://reviews.llvm.org/D15412

llvm-svn: 260112

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[LoopVersioning] Don't assert when there are no memchecks

We shouldn't assert when there are no memchecks, since we
can have SCEV checks. There is already an assert covering
the case where there are

[LoopVersioning] Don't assert when there are no memchecks

We shouldn't assert when there are no memchecks, since we
can have SCEV checks. There is already an assert covering
the case where there are no SCEV checks or memchecks.

This also changes the LAA pointer wrapping versioning test
to use the loop versioning pass (this was how I managed to
trigger the assert in the loop versioning pass).

llvm-svn: 260086

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[SCEV][LAA] Add no wrap SCEV predicates and use use them to improve strided pointer detection

Summary:
This change adds no wrap SCEV predicates with:
- support for runtime checking
- support for

[SCEV][LAA] Add no wrap SCEV predicates and use use them to improve strided pointer detection

Summary:
This change adds no wrap SCEV predicates with:
- support for runtime checking
- support for expression rewriting:
(sext ({x,+,y}) -> {sext(x),+,sext(y)}
(zext ({x,+,y}) -> {zext(x),+,sext(y)}

Note that we are sign extending the increment of the SCEV, even for
the zext case. This is needed to cover the fairly common case where y would
be a (small) negative integer. In order to do this, this change adds two new
flags: nusw and nssw that are applicable to AddRecExprs and permit the
transformations above.

We also change isStridedPtr in LAA to be able to make use of
these predicates. With this feature we should now always be able to
work around overflow issues in the dependence analysis.

Reviewers: mzolotukhin, sanjoy, anemet

Subscribers: mzolotukhin, sanjoy, llvm-commits, rengolin, jmolloy, hfinkel

Differential Revision: http://reviews.llvm.org/D15412

llvm-svn: 260085

show more ...