[IRBuilder] Introduce folder using inst-simplify, use for Or fold.

Alternative to D116817.

This introduces a new value-based folding interface for Or (FoldOr),
which takes 2 values and returns an e

[IRBuilder] Introduce folder using inst-simplify, use for Or fold.

Alternative to D116817.

This introduces a new value-based folding interface for Or (FoldOr),
which takes 2 values and returns an existing Value or a constant if the
Or can be simplified. Otherwise nullptr is returned. This replaces the
more restrictive CreateOr which takes 2 constants.

This is the used to implement a folder that uses InstructionSimplify.
The logic to simplify `Or` instructions is moved there. Subsequent
patches are going to transition other CreateXXX to the more general
FoldXXX interface.

Reviewed By: nikic, lebedev.ri

Differential Revision: https://reviews.llvm.org/D116935

show more ...

[SCEVExpander] Only create trunc when needed.

9345ab3a4550 updated generateOverflowCheck to skip creating checks that
always evaluate to false. This in turn means that we only need to
create TruncTr

[SCEVExpander] Only create trunc when needed.

9345ab3a4550 updated generateOverflowCheck to skip creating checks that
always evaluate to false. This in turn means that we only need to
create TruncTripCount if it is actually used.

Sink the TruncTripCount creating into ComputeEndCheck, so it is only
created when there's an actual check.

show more ...

[SCEVExpander] Only create multiplication if needed.

9345ab3a4550 updated generateOverflowCheck to skip creating checks that
always evaluate to false. This in turn means that we only need to
compute

[SCEVExpander] Only create multiplication if needed.

9345ab3a4550 updated generateOverflowCheck to skip creating checks that
always evaluate to false. This in turn means that we only need to
compute |Step| * Trip count if the result of the multiplication is
actually used.

Sink the multiplication into ComputeEndCheck, so it is only created
when there's an actual check.

show more ...

[SCEVExpander] Only check overflow if it is needed.

9345ab3a4550 updated generateOverflowCheck to skip creating checks that
always evaluate to false. This in turn means that we only need to check
fo

[SCEVExpander] Only check overflow if it is needed.

9345ab3a4550 updated generateOverflowCheck to skip creating checks that
always evaluate to false. This in turn means that we only need to check
for overflows if the result of the multiplication is actually used.

Sink the Or for the overflow check into ComputeEndCheck, so it is only
created when there's an actual check.

show more ...

[SCEVExpander] Skip creating <u 0 check, which is always false.

Unsigned compares of the form <u 0 are always false. Do not create such
a redundant check in generateOverflowCheck.

The patch introdu

[SCEVExpander] Skip creating <u 0 check, which is always false.

Unsigned compares of the form <u 0 are always false. Do not create such
a redundant check in generateOverflowCheck.

The patch introduces a new lambda to create the check, so we can
exit early conveniently and skip creating some instructions feeding the
check.

I am planning to sink a few additional instructions as follow-ups, but I
would prefer to do this separately, to keep the changes and diff
smaller.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D116811

show more ...

[SCEVExpand] Only create required predicate checks.

Currently generateOverflowCheck always creates code for Step being
negative and positive, followed by a select at the end depending on
Step's sign

[SCEVExpand] Only create required predicate checks.

Currently generateOverflowCheck always creates code for Step being
negative and positive, followed by a select at the end depending on
Step's sign.

This patch updates the code to only create either the checks for step
being positive or negative, if the sign is known.

Follow-up to D116696.

Reviewed By: reames

Differential Revision: https://reviews.llvm.org/D116747

show more ...

[SCEVExpand] Do not create redundant 'or false' for pred expansion.

This patch updates SCEVExpander::expandUnionPredicate to not create
redundant 'or false, x' instructions. While those are triviall

[SCEVExpand] Do not create redundant 'or false' for pred expansion.

This patch updates SCEVExpander::expandUnionPredicate to not create
redundant 'or false, x' instructions. While those are trivially
foldable, they can be easily avoided and hinder code that checks the
size/cost of the generated checks before further folds.

I am planning on look into a few other similar improvements to code
generated by SCEVExpander.

I remember a while ago @lebedev.ri working on doing some trivial folds
like that in IRBuilder itself, but there where concerns that such
changes may subtly break existing code.

Reviewed By: reames, lebedev.ri

Differential Revision: https://reviews.llvm.org/D116696

show more ...

Revert rest of `IRBuilderBase`'s short-circuiting folds

Upon further investigation and discussion,
this is actually the opposite direction from what we should be taking,
and this direction wouldn't

Revert rest of `IRBuilderBase`'s short-circuiting folds

Upon further investigation and discussion,
this is actually the opposite direction from what we should be taking,
and this direction wouldn't solve the motivational problem anyway.

Additionally, some more (polly) tests have escaped being updated.
So, let's just take a step back here.

This reverts commit f3190dedeef9da2109ea57e4cb372f295ff53b88.
This reverts commit 749581d21f2b3f53e4fca4eb8728c942d646893b.
This reverts commit f3df87d57e096143670e0fd396e81d43393a2dd2.
This reverts commit ab1dbcecd6f0969976fafd62af34730436ad5944.

show more ...

Revert "[NFC] `IRBuilderBase::CreateAdd()`: place constant onto RHS"

Clang OpenMP codegen tests are failing,
will recommit afterwards.

This reverts commit 4723c9b3c6c46632a5d66e65d198899894b1e2c5.

Revert "[IR] `IRBuilderBase::CreateAdd()`: short-circuit `x + 0` --> `x`"

Clang OpenMP codegen tests are failing.

This reverts commit 288f1f8abe5835180a0021f142043ee261ab3846.
This reverts commit c

Revert "[IR] `IRBuilderBase::CreateAdd()`: short-circuit `x + 0` --> `x`"

Clang OpenMP codegen tests are failing.

This reverts commit 288f1f8abe5835180a0021f142043ee261ab3846.
This reverts commit cb90e5356ac1594e95fed8e208d6e0e9b6a87db1.

show more ...

[IR] `IRBuilderBase::CreateAdd()`: short-circuit `x + 0` --> `x`

There's precedent for that in `CreateOr()`/`CreateAnd()`.

The motivation here is to avoid bloating the run-time check's IR
in `SCEVE

[IR] `IRBuilderBase::CreateAdd()`: short-circuit `x + 0` --> `x`

There's precedent for that in `CreateOr()`/`CreateAnd()`.

The motivation here is to avoid bloating the run-time check's IR
in `SCEVExpander::generateOverflowCheck()`.

Refs. https://reviews.llvm.org/D109368#3089809

show more ...

[NFC] `IRBuilderBase::CreateAdd()`: place constant onto RHS

[IR] `IRBuilderBase::CreateOr()`: fix short-circuiting for constant on LHS

There is no guarantee that the constant is on RHS here,
we have to handle both cases.

Refs. https://reviews.llvm.org/D1093

[IR] `IRBuilderBase::CreateOr()`: fix short-circuiting for constant on LHS

There is no guarantee that the constant is on RHS here,
we have to handle both cases.

Refs. https://reviews.llvm.org/D109368#3089809

show more ...

[IR] `IRBuilderBase::CreateSelect()`: if cond is a constant i1, short-circuit

While we could emit such a tautological `select`,
it will stick around until the next instsimplify invocation,
which may

[IR] `IRBuilderBase::CreateSelect()`: if cond is a constant i1, short-circuit

While we could emit such a tautological `select`,
it will stick around until the next instsimplify invocation,
which may happen after we count the cost of this redundant `select`.
Which is precisely what happens with loop vectorization legality checks,
and that artificially increases the cost of said checks,
which is bad.

There is prior art for this in `IRBuilderBase::CreateAnd()`/`IRBuilderBase::CreateOr()`.

Refs. https://reviews.llvm.org/D109368#3089809

show more ...

[SCEVExpander] Simplify pointer overflow check

This is a followup to D104662 to generate slightly nicer code for
pointer overflow checks. Bypass expandAddToGEP and instead
explicitly generate i8 GEP

[SCEVExpander] Simplify pointer overflow check

This is a followup to D104662 to generate slightly nicer code for
pointer overflow checks. Bypass expandAddToGEP and instead
explicitly generate i8 GEPs. This saves some bitcasts and negates
the value in a more obvious way. In particular, this prevents SCEV
from looking through the umul.with.overflow, same as in the integer
case.

The wrapping-pointer-ni.ll test deserves a comment: Previously,
this generated a typed GEP which used the umulo argument rather
than the multiplication result. This results in more compact IR in
that case, but effectively does the multiplication twice, the
second one is just hidden in the GEP. Reusing the umulo result
seems pretty reasonable to me.

Differential Revision: https://reviews.llvm.org/D109093

show more ...

[SCEVExpander] Prefer pointer expansion for overflow checks

We'd special cased this logic to use pointer types for non-integral pointers, but there's no reason we can't do that for all pointer types

[SCEVExpander] Prefer pointer expansion for overflow checks

We'd special cased this logic to use pointer types for non-integral pointers, but there's no reason we can't do that for all pointer types. Doing it this was has a few advantages:
a) The code itself becomes more straight forward, and easier to test.
b) We avoid introducing ptrtoint into programs which didn't have them in the source.
c) The resulting codegen is easier to analyze and simplify (mostly due to lack of ptrtoint).

Note that there are some test diffs, but a) running them through instcombine helps a ton, and b) there's enough missing obvious transforms on both before and after IR that it's clear this isn't performance sensitive.

This is mostly motivated by cleaning up mentions of non-integrals to have a clearer idea of what we actually need to support.

Differential Revision: https://reviews.llvm.org/D104662

show more ...

[SCEVExpander] ReuseOrCreateCast(): use IRBuilder to actually create the cast

In particular, this allows to create constant expressions
instead of IR Instruction's if the argumen is a constant.

[SCEVExpander] Expand explicit PtrToInt casts just like we would implicit ones

I.e., use GetOptimalInsertionPointForCastOf() helper to get the insertion
point, and try to reuse casts first.

[SCEVExpander] generateOverflowCheck(): explicitly PtrToInt the Start

Currently, InsertNoopCastOfTo() would implicitly insert that cast,
but now that we have SCEVPtrToIntExpr, i'm hoping we could st

[SCEVExpander] generateOverflowCheck(): explicitly PtrToInt the Start

Currently, InsertNoopCastOfTo() would implicitly insert that cast,
but now that we have SCEVPtrToIntExpr, i'm hoping we could stop
InsertNoopCastOfTo() from doing that. But first all users must be fixed.

show more ...

[NFC][SCEVExpander][LoopDistribute] Add test for SCEVPtrToIntExpr in SCEVExpander::generateOverflowCheck()

We shouldn't end up with ptrtoint-of-getelementptr there.

[NFC][SCEVExpander][LoopDistribute] Regenerate scev-inserted-runtime-check.ll check lines

[LoopVersioning] Form dedicated exits for versioned loop to preserve simplify form

The exit blocks of the versioned and non-versioned loops are not dedicated and thus the two loops are not in simpli

[LoopVersioning] Form dedicated exits for versioned loop to preserve simplify form

The exit blocks of the versioned and non-versioned loops are not dedicated and thus the two loops are not in simplify form.
Insert dummy exit blocks after loop versioning with `formDedicatedExits()` to preserve the simplify form for subsequence passes.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D89569

show more ...

[BasicAA] Rename deprecated -basicaa to -basic-aa

Follow-up to D82607
Revert an accidental change (empty.ll) of D82683

Revert "[IRBuilder] Fold consistently for or/and whether constant is LHS or RHS"

This reverts commit r365260 which broke the following tests:

Clang :: CodeGenCXX/cfi-mfcall.cpp
Clang :: Cod

Revert "[IRBuilder] Fold consistently for or/and whether constant is LHS or RHS"

This reverts commit r365260 which broke the following tests:

Clang :: CodeGenCXX/cfi-mfcall.cpp
Clang :: CodeGenObjC/ubsan-nullability.m
LLVM :: Transforms/LoopVectorize/AArch64/pr36032.ll

llvm-svn: 365284

show more ...

[IRBuilder] Fold consistently for or/and whether constant is LHS or RHS

Without this, we have the unfortunate property that tests are dependent on the order of operads passed the CreateOr and Create

[IRBuilder] Fold consistently for or/and whether constant is LHS or RHS

Without this, we have the unfortunate property that tests are dependent on the order of operads passed the CreateOr and CreateAnd functions. In actual usage, we'd promptly optimize them away, but it made tests slightly more verbose than they should have been.

llvm-svn: 365260

show more ...