[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

(cherry picked from commit bcef4d238d113c61127575bf5dd0328f97bda9e9)

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

Reviewed By: efriedma

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

[SimplifyLibCalls] avoid converting pow() to powi() with no FMF

powi() is not a standard math library function; it is specified
with non-strict semantics in the LangRef. We currently require
'afn' t

[SimplifyLibCalls] avoid converting pow() to powi() with no FMF

powi() is not a standard math library function; it is specified
with non-strict semantics in the LangRef. We currently require
'afn' to do this transform when it needs a sqrt(), so I just
extended that requirement to the whole-number exponent too.

This bug was introduced with:
b17754bcaa14
...where we deferred expansion of pow() to later passes.

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[InstCombine] Enable strtol folding with nonnull endptr

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D129593

[SimplifyLibCalls] refactor pow(x, n) expansion where n is a constant integer value

Since the backend's codegen is capable to expand powi into fmul's, it
is not needed anymore to do so in the ::opti

[SimplifyLibCalls] refactor pow(x, n) expansion where n is a constant integer value

Since the backend's codegen is capable to expand powi into fmul's, it
is not needed anymore to do so in the ::optimizePow() function of
SimplifyLibCalls.cpp. What is sufficient is to always turn pow(x, n)
into powi(x, n) for the cases where n is a constant integer value.

Dropping the current expansion code allowed relaxation of the folding
conditions and now this can also happen at optimization levels below
Ofast.

The added CodeGen/AArch64/powi.ll test case ensures that powi is
actually expanded into fmul's, confirming that this refactor did not
cause any performance degradation.

Following an idea proposed by David Sherwood <[email protected]>.

Differential Revision: https://reviews.llvm.org/D128591

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[InstCombine] Fold memchr and strchr equality with first argument

Enhance memchr and strchr handling to simplify calls to the functions
used in equality expressions with the first argument to at mos

[InstCombine] Fold memchr and strchr equality with first argument

Enhance memchr and strchr handling to simplify calls to the functions
used in equality expressions with the first argument to at most two
integer comparisons:

- memchr(A, C, N) == A to N && *A == C for either a dereferenceable
A or a nonzero N,
- strchr(S, C) == S to *S == C for any S and C, and
- strchr(S, '\0') == 0 to true for any S

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D128939

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[InstCombine] Transform strrchr to memrchr for constant strings

Add an emitter for the memrchr common extension and simplify the strrchr
call handler to use it. This enables transforming calls with

[InstCombine] Transform strrchr to memrchr for constant strings

Add an emitter for the memrchr common extension and simplify the strrchr
call handler to use it. This enables transforming calls with the empty
string to the test C ? S : 0.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D128954

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[SimplifyLibCalls] Use inbounds GEP

When converting strchr(p, '\0') to p + strlen(p) we know that
strlen() must return an offset that is inbounds of the allocated
object (otherwise it would be UB),

[SimplifyLibCalls] Use inbounds GEP

When converting strchr(p, '\0') to p + strlen(p) we know that
strlen() must return an offset that is inbounds of the allocated
object (otherwise it would be UB), so we can use an inbounds GEP.
An equivalent argument can be made for the other cases.

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[InstCombine] Fix memrchr logic error that prevents folding

Correct a logic bug in the memrchr enhancement added in D123629 that
makes it ineffective in a subset of cases.

Reviewed By: nikic

Diffe

[InstCombine] Fix memrchr logic error that prevents folding

Correct a logic bug in the memrchr enhancement added in D123629 that
makes it ineffective in a subset of cases.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D128856

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[InstCombine] Fold strncmp of constant arrays and variable size

Extend the solution accepted in D127766 to strncmp and simplify
strncmp(A, B, N) calls with constant A and B and variable N to
the equ

[InstCombine] Fold strncmp of constant arrays and variable size

Extend the solution accepted in D127766 to strncmp and simplify
strncmp(A, B, N) calls with constant A and B and variable N to
the equivalent of

N <= Pos ? 0 : (A < B ? -1 : B < A ? +1 : 0)

where Pos is the offset of either the first mismatch between A
and B or the terminating null character if both A and B are equal
strings.

Reviewed By: courbet

Differential Revision: https://reviews.llvm.org/D128089

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[InstCombine] Look through more casts when folding memchr and memcmp

Enhance getConstantDataArrayInfo to let the memchr and memcmp library
call folders look through arbitrarily long sequences of bit

[InstCombine] Look through more casts when folding memchr and memcmp

Enhance getConstantDataArrayInfo to let the memchr and memcmp library
call folders look through arbitrarily long sequences of bitcast and
GEP instructions.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D128364

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[InstCombine] handle subobjects of constant aggregates

Remove the known limitation of the library function call folders to only
work with top-level arrays of characters (as per the TODO comment in
t

[InstCombine] handle subobjects of constant aggregates

Remove the known limitation of the library function call folders to only
work with top-level arrays of characters (as per the TODO comment in
the code) and allows them to also fold calls involving subobjects of
constant aggregates such as member arrays.

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[InstCombine] Fold memcmp of constant arrays and variable size

The memcmp simplifier is limited to folding to constants calls with constant
arrays and constant sizes. This change adds the ability t

[InstCombine] Fold memcmp of constant arrays and variable size

The memcmp simplifier is limited to folding to constants calls with constant
arrays and constant sizes. This change adds the ability to simplify
memcmp(A, B, N) calls with constant A and B and variable N to the pseudocode
equivalent of

N <= Pos ? 0 : (A < B ? -1 : B < A ? +1 : 0)

where Pos is the offset of the first mismatch between A and B.

Differential Revision: https://reviews.llvm.org/D127766

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[SimplifyLibCalls] Drop duplicate check (NFC)

The same condition already exists inside optimizeMemCmpConstantSize().

[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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[InstCombine] Add substr helper function (NFC).

Reviewed By: nikic

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

[InstCombine] Fold memrchr calls with sequences of identical bytes.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123631

[IR] create and use helper functions that test the signbit; NFCI

Reapply "[BuildLibCalls] Introduce getOrInsertLibFunc() for use when building
libcalls." (was 0f8c626). This reverts commit 14d9390.

The patch previously failed to recognize cases where user had def

Reapply "[BuildLibCalls] Introduce getOrInsertLibFunc() for use when building
libcalls." (was 0f8c626). This reverts commit 14d9390.

The patch previously failed to recognize cases where user had defined a
function alias with an identical name as that of the library
function. Module::getFunction() would then return nullptr which is what the
sanitizer discovered.

In this updated version a new function isLibFuncEmittable() has as well been
introduced which is now used instead of TLI->has() anytime a library function
is to be emitted . It additionally also makes sure there is e.g. no function
alias with the same name in the module.

Reviewed By: Eli Friedman

Differential Revision: https://reviews.llvm.org/D123198

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[InstCombine] Fold strnlen calls in equality to zero.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123818

[SimplifyLibCalls] avoid slicing 64-bit integers in an ILP32 build (PR #54739)

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123472

[InstCombine] Fold strnlen of constant strings.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123817

[InstCombine] Fold memrchr calls with a constant character.

Reviewed By: nikic

Differential Revision: //reviews.llvm.org/D123629

[InstCombine] Fold memrchr calls with constant size, bail on excessive.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123626
Differential Revision: https://reviews.llvm.org/D1

[InstCombine] Fold memrchr calls with constant size, bail on excessive.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123626
Differential Revision: https://reviews.llvm.org/D123628

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[InstCombine] Fold strnlen with a bound of zero and one.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D123816