[InstSimplify] Convert tests to opaque pointers (NFC)

The only interesting test change is in @PR31262, where the following
fold is now performed, while it previously was not:
https://alive2.llvm.org

[InstSimplify] Convert tests to opaque pointers (NFC)

The only interesting test change is in @PR31262, where the following
fold is now performed, while it previously was not:
https://alive2.llvm.org/ce/z/a5Qmr6

llvm/test/Transforms/InstSimplify/ConstProp/gep.ll has not been
updated, because there is a tradeoff between folding and inrange
preservation there that we may want to discuss.

Updates have been performed using:
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34

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[test] Use -passes=instsimplify instead of -instsimplify in a number of tests. NFC

Another step moving away from the deprecated syntax of specifying
pass pipeline in opt.

Differential Revision: htt

[test] Use -passes=instsimplify instead of -instsimplify in a number of tests. NFC

Another step moving away from the deprecated syntax of specifying
pass pipeline in opt.

Differential Revision: https://reviews.llvm.org/D119080

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[InstSimplify] Add more poison folding optimizations

This adds more poison folding optimizations to InstSimplify.

Since all binary operators propagate poison, these are fine.

Also, the preconditio

[InstSimplify] Add more poison folding optimizations

This adds more poison folding optimizations to InstSimplify.

Since all binary operators propagate poison, these are fine.

Also, the precondition of `select cond, undef, x` -> `x` is relaxed to allow the case when `x` is undef.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D104661

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[InstSimplify] allow undef element match in vector select condition value

The semantics of select with undefined/poison condition
are not explicitly stated in the LangRef, but this matches
comments

[InstSimplify] allow undef element match in vector select condition value

The semantics of select with undefined/poison condition
are not explicitly stated in the LangRef, but this matches
comments in the code and Alive2 appears to concur:
https://alive2.llvm.org/ce/z/KXytmd

We can find this pattern after demanded elements transforms.

As noted in D101191, fuzzers are finding infinite loops because
we may not account for this pattern in other passes.

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[InstSimplify] fix potential miscompile in select value equivalence

This is the sibling fix to c590a9880d7a -
as there, we can't subsitute a vector value the equality
compare replacement that we are

[InstSimplify] fix potential miscompile in select value equivalence

This is the sibling fix to c590a9880d7a -
as there, we can't subsitute a vector value the equality
compare replacement that we are trying requires that the
comparison is true for the entire value. Vector select
can be partly true/false.

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[InstSimplify] add test for vector select with operand replacement; NFC

We need a sibling fix to c590a9880d7a
( https://llvm.org/PR49832 ) to avoid miscompiling.

[ValueTracking] Teach canCreateUndefOrPoison that ctpop does not create undef or poison.

This select of ctpop with 0 pattern can get left behind after
loop idiom recognize converts a loop to ctpop.

[ValueTracking] Teach canCreateUndefOrPoison that ctpop does not create undef or poison.

This select of ctpop with 0 pattern can get left behind after
loop idiom recognize converts a loop to ctpop. LLVM 10 was able
to optimize this, but LLVM 11 and later is not. The difference
seems to be that some select transforms are now limited based
on canCreateUndefOrPoison.

Teaching canCreateUndefOrPoison about ctpop restores the
LLVM 10 codegen.

Differential Revision: https://reviews.llvm.org/D99207

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[InstSimplify] Add additional select operand replacement tests (NFC)

This tests for binops with identity elements.

[InstSimplify] Add tests that fold instructions with poison operands (NFC)

[InstSimplify] Clarify use of FixedVectorType in SimplifySelectInst

Folding a select of vector constants that include undef elements only
applies to fixed vectors, but there's no earlier check the t

[InstSimplify] Clarify use of FixedVectorType in SimplifySelectInst

Folding a select of vector constants that include undef elements only
applies to fixed vectors, but there's no earlier check the type is not
scalable so it crashes for scalable vectors. This adds a check so this
optimization is only attempted for fixed vectors.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D92046

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[InstSimplify] Protect against more poison in SimplifyWithOpReplaced (PR47322)

Replace the check for poison-producing instructions in
SimplifyWithOpReplaced() with the generic helper canCreatePoison

[InstSimplify] Protect against more poison in SimplifyWithOpReplaced (PR47322)

Replace the check for poison-producing instructions in
SimplifyWithOpReplaced() with the generic helper canCreatePoison()
that properly handles poisonous shifts and thus avoids the problem
from PR47322.

This additionally fixes a bug in IIQ.UseInstrInfo=false mode, which
previously could have caused this code to ignore poison flags.
Setting UseInstrInfo=false should reduce the possible optimizations,
not increase them.

This is not a full solution to the problem, as poison could be
introduced more indirectly. This is just a minimal, easy to backport
fix.

Differential Revision: https://reviews.llvm.org/D86834

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Recommit "[InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms" and its follow up patches

This recommits the following patches now that D85684 has landed

1cf6f210a2e

Recommit "[InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms" and its follow up patches

This recommits the following patches now that D85684 has landed

1cf6f210a2e [IR] Disable select ? C : undef -> C fold in ConstantFoldSelectInstruction unless we know C isn't poison.
469da663f2d [InstSimplify] Re-enable select ?, undef, X -> X transform when X is provably not poison
122b0640fc9 [InstSimplify] Don't fold vectors of partial undef in SimplifySelectInst if the non-undef element value might produce poison
ac0af12ed2f [InstSimplify] Add test cases for opportunities to fold select ?, X, undef -> X when we can prove X isn't poison
9b1e95329af [InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms

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[InstSimplify] Add test for expand binop undef issue (NFC)

Add test case from https://reviews.llvm.org/D83360#2146539.

Revert "[InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms" and subsequent patches

This reverts most of the following patches due to reports of miscompiles.
I've le

Revert "[InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms" and subsequent patches

This reverts most of the following patches due to reports of miscompiles.
I've left the added test cases with comments updated to be FIXMEs.

1cf6f210a2e [IR] Disable select ? C : undef -> C fold in ConstantFoldSelectInstruction unless we know C isn't poison.
469da663f2d [InstSimplify] Re-enable select ?, undef, X -> X transform when X is provably not poison
122b0640fc9 [InstSimplify] Don't fold vectors of partial undef in SimplifySelectInst if the non-undef element value might produce poison
ac0af12ed2f [InstSimplify] Add test cases for opportunities to fold select ?, X, undef -> X when we can prove X isn't poison
9b1e95329af [InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms

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[IR] Disable select ? C : undef -> C fold in ConstantFoldSelectInstruction unless we know C isn't poison.

This matches the recent change to InstSimplify from D83440.

Differential Revision: https://

[IR] Disable select ? C : undef -> C fold in ConstantFoldSelectInstruction unless we know C isn't poison.

This matches the recent change to InstSimplify from D83440.

Differential Revision: https://reviews.llvm.org/D83535

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[InstSimplify] Re-enable select ?, undef, X -> X transform when X is provably not poison

Follow up from the transform being removed in D83360. If X is probably not poison, then the transform is safe

[InstSimplify] Re-enable select ?, undef, X -> X transform when X is provably not poison

Follow up from the transform being removed in D83360. If X is probably not poison, then the transform is safe.

Still plan to remove or adjust the code from ConstantFolding after this.

Differential Revision: https://reviews.llvm.org/D83440

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[InstSimplify] Don't fold vectors of partial undef in SimplifySelectInst if the non-undef element value might produce poison

We can't fold to the non-undef value unless we know it isn't poison. So c

[InstSimplify] Don't fold vectors of partial undef in SimplifySelectInst if the non-undef element value might produce poison

We can't fold to the non-undef value unless we know it isn't poison. So check each element with isGuaranteedNotToBeUndefOrPoison. This currently rules out all constant expressions.

Differential Revision: https://reviews.llvm.org/D83442

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[InstSimplify] Add test cases for opportunities to fold select ?, X, undef -> X when we can prove X isn't poison

Part of addressing post-commit feedback from D83360

[InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms

As noted here https://lists.llvm.org/pipermail/llvm-dev/2016-October/106182.html and by alive2, this transform is

[InstSimplify] Remove select ?, undef, X -> X and select ?, X, undef -> X transforms

As noted here https://lists.llvm.org/pipermail/llvm-dev/2016-October/106182.html and by alive2, this transform isn't valid. If X is poison this potentially propagates poison when it shouldn't.

This same transform still exists in DAGCombiner.

Differential Revision: https://reviews.llvm.org/D83360

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[InstSimplify] add test for select that should not be simplified; NFC

See discussion in D77868

[InstSimplify] add tests for folding bool select to logic; NFC

[InstSimplify] fold select of vector constants that include undef elements

As mentioned in D72643, we'd like to be able to assert that any select
of equivalent constants has been removed before we'r

[InstSimplify] fold select of vector constants that include undef elements

As mentioned in D72643, we'd like to be able to assert that any select
of equivalent constants has been removed before we're deep into InstCombine.

But there's a loophole in that assertion for vectors with undef elements
that don't match exactly.

This patch should close that gap. If we have undefs, we can't safely
propagate those unless both constants elements for that lane are undef.

Differential Revision: https://reviews.llvm.org/D72958

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[InstSimplify] add test for select of vector constants; NFC

[InstSimplify] add test for select of FP constants; NFC

[InstSimplify] add tests for vector select; NFC