Revert "[InstCombine] Infer nuw for gep inbounds from base of object" (#120460)

Reverts llvm/llvm-project#119225 due to the lack of sanitizer support,
large potential of breaking code containing la

Revert "[InstCombine] Infer nuw for gep inbounds from base of object" (#120460)

Reverts llvm/llvm-project#119225 due to the lack of sanitizer support,
large potential of breaking code containing latent UB, non-trivial
localization and investigation, and what seems to be a bad interaction
with msan (a test is in the works).

Related discussions:
https://github.com/llvm/llvm-project/pull/119225#issuecomment-2551904822
https://github.com/llvm/llvm-project/pull/118472#issuecomment-2549986255

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[InstCombine] Infer nuw for gep inbounds from base of object (#119225)

When we have a gep inbounds from the base of an object (e.g. alloca or
global), we know that the index cannot be negative, as

[InstCombine] Infer nuw for gep inbounds from base of object (#119225)

When we have a gep inbounds from the base of an object (e.g. alloca or
global), we know that the index cannot be negative, as this would go out
of bounds. As such, we can infer nuw as well.

The implementation is a bit stricter than necessary, we could also
accept one unknown index followed by known-non-negative indices.

Proof: https://alive2.llvm.org/ce/z/Hp7-6w (Note that alive2 currently
incorrectly doesn't require the inbounds for the alloca case, see
https://github.com/AliveToolkit/alive2/issues/1138).

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[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

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[InstCombine] Infer nusw + nneg -> nuw for getelementptr (#111144)

If the gep is nusw (usually via inbounds) and the offset is
non-negative, we can infer nuw.

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

[InstCombine] Infer nusw + nneg -> nuw for getelementptr (#111144)

If the gep is nusw (usually via inbounds) and the offset is
non-negative, we can infer nuw.

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

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[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

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[InstCombine] Regenerate all test checks (NFC)

Due to an improvement to name preservation, a lot of InstCombine
tests now show spurious diffs when regenerated.

Rather than regenerating individual f

[InstCombine] Regenerate all test checks (NFC)

Due to an improvement to name preservation, a lot of InstCombine
tests now show spurious diffs when regenerated.

Rather than regenerating individual files when they get touched,
mass-regenerate all UTC-based InstCombine tests. I have then reset
a number of files showing suspicious diffs where the UTC output
has clearly been manually adjusted. I apologize if I missed
anything in the mass of changes.

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[SimplifyLibCalls] Place deref attr even if nonnull already set

If nonnull is already set, we currently skip setting both nonnull
and dereferenceable. Make these independent, to avoid regressions
wh

[SimplifyLibCalls] Place deref attr even if nonnull already set

If nonnull is already set, we currently skip setting both nonnull
and dereferenceable. Make these independent, to avoid regressions
when additional nonnull attributes are inferred earlier.

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[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

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Revert "[ValueTracking] Make getStringLenth aware of strdup"

This reverts commit e810d558093cff40caaa1aff24d289c76c59916d.

The commit was not taken into account the fact that strduped string could

Revert "[ValueTracking] Make getStringLenth aware of strdup"

This reverts commit e810d558093cff40caaa1aff24d289c76c59916d.

The commit was not taken into account the fact that strduped string could be
modified. Checking if such modification happens would make the function very
costly, without a test case in mind it's not worth the effort.

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[ValueTracking] Make getStringLenth aware of strdup

During strlen compile-time evaluation, make it possible to track size of
strduped strings.

Differential Revision: https://reviews.llvm.org/D123497

[SimplifyLibCalls] Remove unnecessary inbounds check

Even if the GEP is not inbounds, the GEP will have provenance of
the global, and accessing past the extent of the global would be
undefined behav

[SimplifyLibCalls] Remove unnecessary inbounds check

Even if the GEP is not inbounds, the GEP will have provenance of
the global, and accessing past the extent of the global would be
undefined behavior.

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[InstCombine] Add strlen of gep test without inbounds (NFC)

[test] Use -passes=instcombine instead of -instcombine in lots of tests. NFC

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

Differential Revision: https://r

[test] Use -passes=instcombine instead of -instcombine in lots of tests. NFC

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

Differential Revision: https://reviews.llvm.org/D119081

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Reland "[Libcalls, Attrs] Annotate libcalls with noundef"

Fixed Clang tests.

Revert "[Libcalls, Attrs] Annotate libcalls with noundef"

This reverts commit 33b0c63775ce58014c55e285671e3315104a6076. Bots are failing. Some Clang tests need to be updated too.

[Libcalls, Attrs] Annotate libcalls with noundef

I think we can use here same logic as for nonnull.

strlen(X) - X must be noundef => valid pointer.

for libcalls with size arg, we add noundef only

[Libcalls, Attrs] Annotate libcalls with noundef

I think we can use here same logic as for nonnull.

strlen(X) - X must be noundef => valid pointer.

for libcalls with size arg, we add noundef only if size is known and greater than 0 - so pointers must be noundef (valid ones)

Reviewed By: jdoerfert, aqjune

Differential Revision: https://reviews.llvm.org/D95122

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[SimplifyLibCalls] Remove over-eager early return in strlen optzns.

Currently we bail out early for strlen calls with a GEP operand, if none
of the GEP specific optimizations fire. But there could b

[SimplifyLibCalls] Remove over-eager early return in strlen optzns.

Currently we bail out early for strlen calls with a GEP operand, if none
of the GEP specific optimizations fire. But there could be later
optimizations that still apply, which we currently miss out on.

An example is that we do not apply the following optimization
strlen(x) == 0 --> *x == 0

Unless I am missing something, there seems to be no reason for bailing
out early there.

Fixes PR47149.

Reviewed By: lebedev.ri, xbolva00

Differential Revision: https://reviews.llvm.org/D85886

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[InstCombine] Precommit tests for PR47149.

[IR] Convert null-pointer-is-valid into an enum attribute

The "null-pointer-is-valid" attribute needs to be checked by many
pointer-related combines. To make the check more efficient, convert
it fro

[IR] Convert null-pointer-is-valid into an enum attribute

The "null-pointer-is-valid" attribute needs to be checked by many
pointer-related combines. To make the check more efficient, convert
it from a string into an enum attribute.

In the future, this attribute may be replaced with data layout
properties.

Differential Revision: https://reviews.llvm.org/D78862

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[SimplifyLibCalls] Mark known arguments with nonnull

Reviewers: efriedma, jdoerfert

Reviewed By: jdoerfert

Subscribers: ychen, rsmith, joerg, aaron.ballman, lebedev.ri, uenoku, jdoerfert, hfinkel,

[SimplifyLibCalls] Mark known arguments with nonnull

Reviewers: efriedma, jdoerfert

Reviewed By: jdoerfert

Subscribers: ychen, rsmith, joerg, aaron.ballman, lebedev.ri, uenoku, jdoerfert, hfinkel, javed.absar, spatel, dmgreen, llvm-commits

Differential Revision: https://reviews.llvm.org/D53342

llvm-svn: 372091

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Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

[ValueTracking] More accurate unsigned sub overflow detection

Second part of D58593.

Compute precise overflow conditions based on all known bits, rather
than just the sign bits. Unsigned a - b over

[ValueTracking] More accurate unsigned sub overflow detection

Second part of D58593.

Compute precise overflow conditions based on all known bits, rather
than just the sign bits. Unsigned a - b overflows iff a < b, and we
can determine whether this always/never happens based on the minimal
and maximal values achievable for a and b subject to the known bits
constraint.

llvm-svn: 355109

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llvm: Add support for "-fno-delete-null-pointer-checks"

Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More

llvm: Add support for "-fno-delete-null-pointer-checks"

Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More details : https://lkml.org/lkml/2018/4/4/601

GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.

-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.

This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.

Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv

Reviewed By: efriedma, george.burgess.iv

Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47895

llvm-svn: 336613

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Merge isKnownNonNull into isKnownNonZero
It now knows the tricks of both functions.
Also, fix a bug that considered allocas of non-zero address space to be always non null

Differential Revision: htt

Merge isKnownNonNull into isKnownNonZero
It now knows the tricks of both functions.
Also, fix a bug that considered allocas of non-zero address space to be always non null

Differential Revision: https://reviews.llvm.org/D37628

llvm-svn: 312869

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strlen-1.ll: Fix test

Change test for `strlen(x) == 0 --> *x == 0` to actually test the
pattern.

llvm-svn: 302094