Rename llvm::array_lengthof into llvm::size to match std::size from C++17

As a conquence move llvm::array_lengthof from STLExtras.h to
STLForwardCompat.h (which is included by STLExtras.h so no buil

Rename llvm::array_lengthof into llvm::size to match std::size from C++17

As a conquence move llvm::array_lengthof from STLExtras.h to
STLForwardCompat.h (which is included by STLExtras.h so no build
breakage expected).

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[InstCombine] try to fold binop with phi operands

This is an alternate version of D115914 that handles/tests all binary opcodes.

I suspect that we don't see these patterns too often because -simpli

[InstCombine] try to fold binop with phi operands

This is an alternate version of D115914 that handles/tests all binary opcodes.

I suspect that we don't see these patterns too often because -simplifycfg
would convert the minimal cases into selects rather than leave them in phi form
(note: instcombine has logic holes for combining the select patterns too though,
so that's another potential patch).

We only create a new binop in a predecessor that unconditionally branches to
the final block.
https://alive2.llvm.org/ce/z/C57M2F
https://alive2.llvm.org/ce/z/WHwAoU (not safe to speculate an sdiv for example)
https://alive2.llvm.org/ce/z/rdVUvW (but it is ok on this path)

Differential Revision: https://reviews.llvm.org/D117110

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[InstCombine] reduce code duplication; NFC

[InstCombine] Simplify addends reordering logic

Previously some constants were not pushed to the top of the resulting
expression tree as intended by the algorithm. We can remove the logic
from simpl

[InstCombine] Simplify addends reordering logic

Previously some constants were not pushed to the top of the resulting
expression tree as intended by the algorithm. We can remove the logic
from simplifyFAdd and rely on SimplifyAssociativeOrCommutative to do
that.

Differential Revision: https://reviews.llvm.org/D117302

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[InstCombine] FP with reassoc FMF: (X * C) + X --> X * (MulC + 1.0)

This fold already exists for scalars via FAddCombine (and that's
why 2 of the tests are only changed cosmetically), but that code

[InstCombine] FP with reassoc FMF: (X * C) + X --> X * (MulC + 1.0)

This fold already exists for scalars via FAddCombine (and that's
why 2 of the tests are only changed cosmetically), but that code
misses vectors and has largely been replaced by simpler folds
over time, so this is another step towards removing it.

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[InstCombine] fix code comment to match code; NFC

[InstCombine] fold sub-of-umax to 0-usubsat

Op0 - umax(X, Op0) --> 0 - usub.sat(X, Op1)

I'm not sure if this is really an improvement in IR because
we probably have better recognition/analysis for

[InstCombine] fold sub-of-umax to 0-usubsat

Op0 - umax(X, Op0) --> 0 - usub.sat(X, Op1)

I'm not sure if this is really an improvement in IR because
we probably have better recognition/analysis for min/max,
but this lines up with the fold we do for the icmp+select
idiom and removes another diff from D98152.

This is similar to the previous fold in the code that was
added with:
83c2fb9f66be
baa6a851308d

https://alive2.llvm.org/ce/z/5MrVB9

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[InstCombine] allow commute in sub-of-umax fold

This fold was added with:
83c2fb9f66be
...but missed the commuted pattern:
https://alive2.llvm.org/ce/z/_tYEGy

[InstCombine] match usub.sat from umax intrinsic

umax(X, Op1) - Op1 --> usub.sat(X, Op1)

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

This happens in 2 or more steps with an icmp-select idiom
instead of an

[InstCombine] match usub.sat from umax intrinsic

umax(X, Op1) - Op1 --> usub.sat(X, Op1)

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

This happens in 2 or more steps with an icmp-select idiom
instead of an intrinsic. This is another step towards
canonicalization of the min/max intrinsics. See:
D98152

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[APInt] Stop using soft-deprecated constructors and methods in llvm. NFC.

Stop using APInt constructors and methods that were soft-deprecated in
D109483. This fixes all the uses I found in llvm, exc

[APInt] Stop using soft-deprecated constructors and methods in llvm. NFC.

Stop using APInt constructors and methods that were soft-deprecated in
D109483. This fixes all the uses I found in llvm, except for the APInt
unit tests which should still test the deprecated methods.

Differential Revision: https://reviews.llvm.org/D110807

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Fixed more warnings in LLVM produced by -Wbitwise-instead-of-logical

[InstCombine] update code/test comments; NFC

Follow-up for post-commit suggestion on:
28afaed691a0a7ca46bb9f64fac11

The comments were partly copied from the original
code, but not updated to match

[InstCombine] update code/test comments; NFC

Follow-up for post-commit suggestion on:
28afaed691a0a7ca46bb9f64fac11

The comments were partly copied from the original
code, but not updated to match the new code.

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[InstCombine] fold sub of min/max intrinsics with invertible ops

This is a translation of the existing code to handle the intrinsics
and another step towards D98152.

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

[InstCombine] fold sub of min/max intrinsics with invertible ops

This is a translation of the existing code to handle the intrinsics
and another step towards D98152.

https://alive2.llvm.org/ce/z/jA7eBC

This pattern is already handled by underlying folds if there are
less uses, so the minimal tests in this case have extra uses.

The larger cmyk tests show the motivation - when combined with
other folds, we invert a larger sequence and eliminate 'not' ops.

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[InstCombine] generalize subtract with 'not' operands; 2nd try

This is a re-try of 3aa009cc87e3 which was reverted at
9577fac0fddf because it caused an infinite loop.

For the extra test case, eithe

[InstCombine] generalize subtract with 'not' operands; 2nd try

This is a re-try of 3aa009cc87e3 which was reverted at
9577fac0fddf because it caused an infinite loop.

For the extra test case, either re-ordering the transforms
or adding the extra clause to avoid sub-of-sub is enough
to prevent the infinite compile, but I'm doing both to be
safer.

Original commit message:
The motivation was to get min/max intrinsics to parity
with cmp+select idioms, but this unlocks a few more
folds because isFreeToInvert recognizes add/sub with
constants too.

In the min/max example, we have too many extra uses
for smaller folds to improve things, but this fold
is able to eliminate uses even though we can't reduce
the number of instructions.

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Revert "[InstCombine] generalize subtract with 'not' operands"

This reverts commit 3aa009cc87e3789ac44bbb98b04846736373e08f.

The reverted commit causes an infinite loop in instcombine. See PR51584.

[InstCombine] generalize subtract with 'not' operands

The motivation was to get min/max intrinsics to parity
with cmp+select idioms, but this unlocks a few more
folds because isFreeToInvert recogniz

[InstCombine] generalize subtract with 'not' operands

The motivation was to get min/max intrinsics to parity
with cmp+select idioms, but this unlocks a few more
folds because isFreeToInvert recognizes add/sub with
constants too.

In the min/max example, we have too many extra uses
for smaller folds to improve things, but this fold
is able to eliminate uses even though we can't reduce
the number of instructions.

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[InstCombine] combine constants by reassociating add/sub/add

This may overlap partially with the reassociate pass,
but it seems simple enough that we should try it here
in InstCombine to enable othe

[InstCombine] combine constants by reassociating add/sub/add

This may overlap partially with the reassociate pass,
but it seems simple enough that we should try it here
in InstCombine to enable other folds.

This shows up as an opportunity and potential regression
if we improve a subtract fold with 'not' ops to be more
general.

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[InstCombine] fold reassociative FP add into start value of fadd reduction

This pattern is visible in unrolled and vectorized loops.
Although the backend seems to be able to reassociate to
ideal for

[InstCombine] fold reassociative FP add into start value of fadd reduction

This pattern is visible in unrolled and vectorized loops.
Although the backend seems to be able to reassociate to
ideal form in the examples I looked at, we might as well
do that in IR for efficiency.

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[InstCombine] fix nsz (fast-math) propagation from fneg-of-select

As discussed in the post-commit comments for:
3cdd05e519dd

It seems to be safe to propagate all flags from the final fneg
except fo

[InstCombine] fix nsz (fast-math) propagation from fneg-of-select

As discussed in the post-commit comments for:
3cdd05e519dd

It seems to be safe to propagate all flags from the final fneg
except for 'nsz' to the new select:
https://alive2.llvm.org/ce/z/J_APDc

nsz has unique FMF semantics: it is not poison, it is only
"insignificant" in the calculation according to the LangRef.

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[InstCombine] intersect nsz and ninf fast-math-flags (FMF) for fneg(fdiv) fold

https://alive2.llvm.org/ce/z/3KPvih

https://llvm.org/PR49654

[InstCombine] refactor match clauses; NFC

We need to adjust the FMF propagation on at least
one of these transforms as discussed in:
https://llvm.org/PR49654
...so this should make it easier to inte

[InstCombine] refactor match clauses; NFC

We need to adjust the FMF propagation on at least
one of these transforms as discussed in:
https://llvm.org/PR49654
...so this should make it easier to intersect flags.

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[InstCombine] fold fnegs around select

This is one of the folds requested in:
https://llvm.org/PR39480

https://alive2.llvm.org/ce/z/NczU3V

Note - this uses the normal FMF propagation logic
(flags

[InstCombine] fold fnegs around select

This is one of the folds requested in:
https://llvm.org/PR39480

https://alive2.llvm.org/ce/z/NczU3V

Note - this uses the normal FMF propagation logic
(flags transfer from the final value to new/intermediate ops).
It's not clear if this matches what Alive2 implements,
so we may want to adjust one or the other.

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[InstCombine] C - ctpop(a) - > ctpop(~a)) if C is bitwidth (PR50104)

Proof: https://alive2.llvm.org/ce/z/mncA9K
Solves https://bugs.llvm.org/show_bug.cgi?id=50104

Reviewed By: spatel

Differential

[InstCombine] C - ctpop(a) - > ctpop(~a)) if C is bitwidth (PR50104)

Proof: https://alive2.llvm.org/ce/z/mncA9K
Solves https://bugs.llvm.org/show_bug.cgi?id=50104

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D101257

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[InstCombine] ctpop(X) + ctpop(Y) => ctpop(X | Y) if X and Y have no common bits (PR48999)

For example:

```
int src(unsigned int a, unsigned int b)
{
return __builtin_popcount(a << 16) + __buil

[InstCombine] ctpop(X) + ctpop(Y) => ctpop(X | Y) if X and Y have no common bits (PR48999)

For example:

```
int src(unsigned int a, unsigned int b)
{
return __builtin_popcount(a << 16) + __builtin_popcount(b >> 16);
}

int tgt(unsigned int a, unsigned int b)
{
return __builtin_popcount((a << 16) | (b >> 16));
}
```

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D101210

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[InstCombine] X - usub.sat(X, Y) => umin(X, Y)

Pattern regressed in LLVM 9 with the introduction of usub.sat.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42178#c2

Reviewed By: nikic

Differential

[InstCombine] X - usub.sat(X, Y) => umin(X, Y)

Pattern regressed in LLVM 9 with the introduction of usub.sat.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42178#c2

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D101184

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