[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] Set `samesign` when converting signed predicates into unsigned (#112642)

Alive2: https://alive2.llvm.org/ce/z/6cqdt-

[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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[Tests] Preserve original test scenario

[SLC] Use unsigned char to fix test failures on some platforms

[SimplifyLibCalls] Transform memchr(STR, C, N) to chain of ORs

Motivation:

```
#include <string_view>

size_t findFirst_ABCDEF(std::string_view sv) {
return sv.find_first_of("ABCDEF");
}
```

mem

[SimplifyLibCalls] Transform memchr(STR, C, N) to chain of ORs

Motivation:

```
#include <string_view>

size_t findFirst_ABCDEF(std::string_view sv) {
return sv.find_first_of("ABCDEF");
}
```

memchr("ABCDEF", C, 6) != NULL -> (C == 'A' || C == 'B' || C == 'C' || C == 'D' || C == 'E' || C == 'F') != 0

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D128011

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[InstCombine] add nuw to any (1<<x)

https://alive2.llvm.org/ce/z/9EjDKE

This was mentioned as a missing fold in D139598.

It can unlock follow-on folds in some cases.
This verifies one of the chang

[InstCombine] add nuw to any (1<<x)

https://alive2.llvm.org/ce/z/9EjDKE

This was mentioned as a missing fold in D139598.

It can unlock follow-on folds in some cases.
This verifies one of the changed tests:
https://alive2.llvm.org/ce/z/B_btDM

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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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[InstCombine] canonicalize 'icmp (trunc X), C' to 'icmp (X & Mask), C'

I looked at canonicalizing in the other direction, but that causes
many potential regressions and infinite loops because we alr

[InstCombine] canonicalize 'icmp (trunc X), C' to 'icmp (X & Mask), C'

I looked at canonicalizing in the other direction, but that causes
many potential regressions and infinite loops because we already
(possibly wrongly) canonicalize "trunc X to i1" into an and+icmp.

This has a data layout restriction to avoid creating illegal
mask instructions, but we could remove that if we can show
that the backend can undo this when needed.

The motivating example from issue #56119 is modeled by the
PhaseOrdering test.

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[InstCombine] Fold memchr of sequences of same characters

Enhance memchr libcall folder to handle constant arrays consisting
of one or two sequences of cosecutive equal characters.

Reviewed By: nik

[InstCombine] Fold memchr of sequences of same characters

Enhance memchr libcall folder to handle constant arrays consisting
of one or two sequences of cosecutive equal characters.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D126515

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[SimplifyLibCalls] Don't mark memchr() memory as fully dereferenceable

C11 specifies memchr() as follows:

> The memchr function locates the first occurrence of c (converted
> to an unsigned char) i

[SimplifyLibCalls] Don't mark memchr() memory as fully dereferenceable

C11 specifies memchr() as follows:

> The memchr function locates the first occurrence of c (converted
> to an unsigned char) in the initial n characters (each interpreted
> as unsigned char) of the object pointed to by s. The implementation
> shall behave as if it reads the characters sequentially and stops
> as soon as a matching character is found.

In particular, it is well-defined to specify a memchr size larger
than the underlying object, as long as the character is found before
the end of the object.

Differential Revision: https://reviews.llvm.org/D123665

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[SimplifyLibCalls] Fold memchr() with size 1

If the memchr() size is 1, then we can convert the call into a
single-byte comparison. This works even if both the string and the
character are unknown.

[SimplifyLibCalls] Fold memchr() with size 1

If the memchr() size is 1, then we can convert the call into a
single-byte comparison. This works even if both the string and the
character are unknown.

Split off from https://reviews.llvm.org/D122836.

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[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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[SimplifyLibCalls] Fix memchr opt to use CreateLogicalAnd

This fixes a bug at LibCallSimplifier::optimizeMemChr which does the following transformation:

```
// memchr("\r\n", C, 2) != nullptr -> (1

[SimplifyLibCalls] Fix memchr opt to use CreateLogicalAnd

This fixes a bug at LibCallSimplifier::optimizeMemChr which does the following transformation:

```
// memchr("\r\n", C, 2) != nullptr -> (1 << C & ((1 << '\r') | (1 << '\n')))
// != 0
// after bounds check.
```

As written above, a bounds check on C (whether it is less than integer bitwidth) is done before doing `1 << C` otherwise 1 << C will overflow.
If the bounds check is false, the result of (1 << C & ...) must not be used at all, otherwise the result of shift (which is poison) will contaminate the whole results.
A correct way to encode this is `select i1 (bounds check), (1 << C & ...), false` because select does not allow the unused operand to contaminate the result.
However, this optimization was introducing `and (bounds check), (1 << C & ...)` which cannot do that.

The bug was found from compilation of this C++ code: https://reviews.llvm.org/rG2fd3037ac615#1007197

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D104901

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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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[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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[SimplifyLibCalls] Add dereferenceable bytes from known callsites

Summary:
int mm(char *a, char *b) {
return memcmp(a,b,16);
}

Currently:
define dso_local i32 @mm(i8* nocapture readonly %a, i8*

[SimplifyLibCalls] Add dereferenceable bytes from known callsites

Summary:
int mm(char *a, char *b) {
return memcmp(a,b,16);
}

Currently:
define dso_local i32 @mm(i8* nocapture readonly %a, i8* nocapture readonly %b) local_unnamed_addr #1 {
entry:
%call = tail call i32 @memcmp(i8* %a, i8* %b, i64 16)
ret i32 %call
}

After patch:
define dso_local i32 @mm(i8* nocapture readonly %a, i8* nocapture readonly %b) local_unnamed_addr #1 {
entry:
%call = tail call i32 @memcmp(i8* dereferenceable(16) %a, i8* dereferenceable(16) %b, i64 16)
ret i32 %call
}




Reviewers: jdoerfert, efriedma

Reviewed By: jdoerfert

Subscribers: javed.absar, spatel, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66079

llvm-svn: 368657

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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

[SimplifyLibCalls] Fix memchr expansion for constant strings.

The C standard says "The memchr function locates the first
occurrence of c (converted to an unsigned char)[...]". The expansion
was mis

[SimplifyLibCalls] Fix memchr expansion for constant strings.

The C standard says "The memchr function locates the first
occurrence of c (converted to an unsigned char)[...]". The expansion
was missing the conversion to unsigned char.

Fixes https://bugs.llvm.org/show_bug.cgi?id=39041 .

Differential Revision: https://reviews.llvm.org/D55947

llvm-svn: 350775

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SimplifyLibCalls: Optimize wcslen

Refactor the strlen optimization code to work for both strlen and wcslen.

This especially helps with programs in the wild where people pass
L"string"s to const std

SimplifyLibCalls: Optimize wcslen

Refactor the strlen optimization code to work for both strlen and wcslen.

This especially helps with programs in the wild where people pass
L"string"s to const std::wstring& function parameters and the wstring
constructor gets inlined.

This also fixes a lingerind API problem/bug in getConstantStringInfo()
where zeroinitializers would always give you an empty string (without a
length) back regardless of the actual length of the initializer which
did not work well in the TrimAtNul==false causing the PR mentioned
below.

Note that the fixed getConstantStringInfo() needed fixes to SelectionDAG
memcpy lowering and may lead to some cases for out-of-bounds
zeroinitializer accesses not getting optimized anymore. So some code
with UB may produce out of bound memory reads now instead of just
producing zeros.

The refactoring "accidentally" fixes http://llvm.org/PR32124

Differential Revision: https://reviews.llvm.org/D32839

llvm-svn: 303461

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[InstCombine] regenerate checks

llvm-svn: 268244