[LLVM][IR] Use splat syntax when printing Constant[Data]Vector. (#112548)

[InstCombine] Remove some of the complexity-based canonicalization (#91185)

The idea behind this canonicalization is that it allows us to handle less
patterns, because we know that some will be can

[InstCombine] Remove some of the complexity-based canonicalization (#91185)

The idea behind this canonicalization is that it allows us to handle less
patterns, because we know that some will be canonicalized away. This is
indeed very useful to e.g. know that constants are always on the right.

However, this is only useful if the canonicalization is actually
reliable. This is the case for constants, but not for arguments: Moving
these to the right makes it look like the "more complex" expression is
guaranteed to be on the left, but this is not actually the case in
practice. It fails as soon as you replace the argument with another
instruction.

The end result is that it looks like things correctly work in tests,
while they actually don't. We use the "thwart complexity-based
canonicalization" trick to handle this in tests, but it's often a
challenge for new contributors to get this right, and based on the
regressions this PR originally exposed, we clearly don't get this right
in many cases.

For this reason, I think that it's better to remove this complexity
canonicalization. It will make it much easier to write tests for
commuted cases and make sure that they are handled.

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[InstCombine] Transform (icmp eq/ne rotate(X,AX),rotate(Y,AY)) -> (icmp eq/ne rotate(Y,AX-AY))

Only do so if we don't create more instructions, so either both
rotates have one use or one of the rota

[InstCombine] Transform (icmp eq/ne rotate(X,AX),rotate(Y,AY)) -> (icmp eq/ne rotate(Y,AX-AY))

Only do so if we don't create more instructions, so either both
rotates have one use or one of the rotates has one use and both `AX`
and `AY` are constant.
Proof: https://alive2.llvm.org/ce/z/rVmJgz

Differential Revision: https://reviews.llvm.org/D152348

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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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[InstCombine] ror/rol(X, RotAmt) == C --> X == rol/ror(C, RotAmt) (PR51567)

```
----------------------------------------
define i1 @src(i32 %0) {
%1:
%2 = fshl i32 %0, i32 %0, i32 25
%3 = icmp

[InstCombine] ror/rol(X, RotAmt) == C --> X == rol/ror(C, RotAmt) (PR51567)

```
----------------------------------------
define i1 @src(i32 %0) {
%1:
%2 = fshl i32 %0, i32 %0, i32 25
%3 = icmp eq i32 %2, 5
ret i1 %3
}
=>
define i1 @tgt(i32 %0) {
%1:
%2 = icmp eq i32 %0, 640
ret i1 %2
}
Transformation seems to be correct!
```

https://alive2.llvm.org/ce/z/GdY8Jm

Solves PR51567

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D109283

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[NFC] Added tests for D109283

[InstCombine] rotate(X,Z) eq/ne rotate(Y,Z) ---> X eq/ne Y (PR51565)

```

----------------------------------------
define i1 @src(i8 %x, i8 %y, i8 %z) {
%0:
%f = fshl i8 %x, i8 %x, i8 %z
%f2 = f

[InstCombine] rotate(X,Z) eq/ne rotate(Y,Z) ---> X eq/ne Y (PR51565)

```

----------------------------------------
define i1 @src(i8 %x, i8 %y, i8 %z) {
%0:
%f = fshl i8 %x, i8 %x, i8 %z
%f2 = fshl i8 %y, i8 %y, i8 %z
%r = icmp eq i8 %f, %f2
ret i1 %r
}
=>
define i1 @tgt(i8 %x, i8 %y, i8 %z) {
%0:
%r = icmp eq i8 %x, %y
ret i1 %r
}
Transformation seems to be correct!

```

https://alive2.llvm.org/ce/z/qAZp8f

Solves PR51565

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D109271

show more ...

[NFC] Added tests for PR51565