[ConstantFolding] Infer getelementptr nuw flag (#119214)

Infer nuw from nusw and nneg. This is the constant expression variant of
https://github.com/llvm/llvm-project/pull/111144.

Proof: https:/

[ConstantFolding] Infer getelementptr nuw flag (#119214)

Infer nuw from nusw and nneg. This is the constant expression variant of
https://github.com/llvm/llvm-project/pull/111144.

Proof: https://alive2.llvm.org/ce/z/ihztLy

show more ...

[ConstantFolding] Canonicalize constexpr GEPs to i8 (#89872)

This patch canonicalizes constant expression GEPs to use i8 source
element type, aka ptradd. This is the ConstantFolding equivalent of t

[ConstantFolding] Canonicalize constexpr GEPs to i8 (#89872)

This patch canonicalizes constant expression GEPs to use i8 source
element type, aka ptradd. This is the ConstantFolding equivalent of the
InstCombine canonicalization introduced in #68882.

I believe all our optimizations working on constant expression GEPs
(like GlobalOpt etc) have already been switched to work on offsets, so I
don't expect any significant fallout from this change.

This is part of:
https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699

show more ...

[InstCombine] Canonicalize constant GEPs to i8 source element type (#68882)

This patch canonicalizes getelementptr instructions with constant
indices to use the `i8` source element type. This makes

[InstCombine] Canonicalize constant GEPs to i8 source element type (#68882)

This patch canonicalizes getelementptr instructions with constant
indices to use the `i8` source element type. This makes it easier for
optimizations to recognize that two GEPs are identical, because they
don't need to see past many different ways to express the same offset.

This is a first step towards
https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699.
This is limited to constant GEPs only for now, as they have a clear
canonical form, while we're not yet sure how exactly to deal with
variable indices.

The test llvm/test/Transforms/PhaseOrdering/switch_with_geps.ll gives
two representative examples of the kind of optimization improvement we
expect from this change. In the first test SimplifyCFG can now realize
that all switch branches are actually the same. In the second test it
can convert it into simple arithmetic. These are representative of
common optimization failures we see in Rust.

Fixes https://github.com/llvm/llvm-project/issues/69841.

show more ...

[ValueTracking] Handle constant exprs in isKnownNonZero()

Handle constant expressions by falling through to the general
operator-based code. In particular, this adds support for bitcast
and GEP expr

[ValueTracking] Handle constant exprs in isKnownNonZero()

Handle constant expressions by falling through to the general
operator-based code. In particular, this adds support for bitcast
and GEP expressions.

show more ...

[test][InstCombine] Update some more test cases to use opaque pointers

These tests cases were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34,
but there

[test][InstCombine] Update some more test cases to use opaque pointers

These tests cases were converted using the script at
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34,
but there was also a need to re-run update_test_checks.py (impacting
nonnull/dereferencable attributes).

Differential Revision: https://reviews.llvm.org/D135095

show more ...

[InstCombine] Correct strtol folding with nonnull endptr

Reflect in the pointer's offset the length of the leading part
of the consumed string preceding the first converted digit.

Reviewed By: efri

[InstCombine] Correct strtol folding with nonnull endptr

Reflect in the pointer's offset the length of the leading part
of the consumed string preceding the first converted digit.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D130912

show more ...

[InstCombine] Fold strtoul and strtoull and avoid PR #56293

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D129224