Fix #1371.

Not sure about whether we could remove `convertTypeForMem` completely.
Let's fix the doc first.

This change moves all declarations of emit* functions in
CIRGenFunction.h into a common location and sorts them alphabetically.
The goal of this change is to make it easier to keep upstream and
incubator code in a consistent location, making functions easier to find
for upstreaming and minimizing conflicts in the incubator when rebasing.

I did most of this sort manually, and I've probably been inconsistent in
how I treat sorting of uppercase versus lowercase. I made no attempt to
provide a rule for ordering different declarations of functions with the
same name. We can improve on that over time if anyone feels the need.

I tried very hard not to drop comments (one of the reasons I had to do
this manually), but I may have lost a few.

This change loses the grouping of some declarations that were co-located
by common purpose, but most of the declarations lacked a coherent
ordering, so I think this is a step forward overall.

This is a rebased version of the inactive PR #1380.

---------

Co-authored-by: koparasy <[email protected]>

Adds implementation for ATanOp's lowering ThroughMLIR.

Lower `vabds_f32` and `vabdd_f64`

Adds implementation for ACosOp's lowering ThroughMLIR.

Lower vmaxv_s32

Adds implementation for ASinOp's lowering ThroughMLIR.

Lower vmaxv_u32

Lower vmaxvq_f64

- Part of #70.

Lower vmaxnmvq f32 and f64

In the review for upstreaming unary operation support
(llvm/llvm-project#131369), it was suggested
that the VisitPlus and VisitMinus functions should be combined. This is
a backport of that refactoring.

This also removes some unused `#include`s.

I choose to allow lowering to LLVM dialect when we're lowering CIR to
MLIR core dialects, because some operations don't have their
counterparts in these dialects (for example, `UnreachableOp ->
llvm.unreachable` and `LLVMIntrinsicCallOp -> cir.llvm.intr.xxx`). I
don't think we can delay them to the MLIR->LLVM pass as it seems we
assume all CIR operations have been lowered after CIR->MLIR conversion.

Co-authored-by: Yue Huang <[email protected]>

…#1543)

- Part of #1192

Lower vmaxnmv_f32

Update getZeroInitAttr to cover more FP types, Backport from
(llvm/llvm-project#133100)

Adds implementation for TanOp's lowering via ThroughMLIR.

Upstream commit changed behavior
llvm/llvm-project@ff585fe
I tested in original clang and it produced the same IR with clangir.
Related: #1497

…nmvq_f32 (#1546)

ower vminnmv_f32, vminnmvq_f64 and vminnmvq_f32

…#1547)

When a pointer variable is initialized with a null pointer, the AST
contains a NullToPointer cast. If we just emit a null pointer of the
correct type, we will miss any side effects that occur in the
initializer. This change adds code to emit the initializer expression if
it is not a simple constant.

This results in an extra null pointer constant being emitted when the
expression has side effects, but the constant emitted while visiting the
expression does not have the correct type, so the alternative would be
to capture the emitted constant and bitcast it to the correct type. An
extra constant seems less intrusive than an unnecessary bitcast.

Lower vminv_s32

Lower vminv_u32

#1552)

These entries exist in OG but are not present in CIR codegen.

Added:
- `cos`
- `floor`
- `round`
- `rint`
- `nearbyint`
- `sin`
- `sqrt`
- `tan`
- `trunc`

Lower vminvq_f32 and vminvq_f64

We were missing argument handling for `-fclangir-idiom-recognizer` on
its own, and were not propagating `-fclangir-lib-opt` for the clang
toolchain.

Failure:
```
calling convention does not permit calls
  call spir_kernel void @bar(ptr addrspace(1) %10)
fatal error: error in backend: Lowering from LLVMIR dialect to llvm IR failed!
```

…urn}

This makes it on par with OG but does not add anything just yet (same NYI
asserts should fail).

This will enable handling for records (coming next)

This includes member data attribute in to enable and existing test.
LLVM lowering is follow up work.

Fixes XFAIL in ../clang/test/CIR/CodeGen/nonzeroinit-struct.cpp

This PR is inspired by the discussion in
#1745 (comment).
When changing the type of

```mlir
IndexAttr:$index,
I64Attr:$index
```

in `GetMemberOp`, the `getIndex` method becomes auto-generated.
This allows us to remove the custom builder previously defined for this
operation.

Backport AbstractConditionalOperator for ComplexType from the upstream

Fix: #1788

Previously, when an array of destructible object went out of scope, the
object destructors were called in the same order that they were
constructed. This is incorrect. The objects should be destructed in
reverse order. This change fixes that.

This fixes #1759

Backport LValueBitcast support for ComplexType from the upstream