[clang] [CLANG] Full support of complex multiplication and division. (PR #81514)

[Andy Kaylor via cfe-commits]

================

----------------
andykaylor wrote:

Can you add test cases for targets that will have problems with promotion. Something like this?

```
// RUN: %clang_cc1 -triple x86_64-windows-pc \
// RUN: -complex-range=promoted -emit-llvm -o - %s \
// RUN: | FileCheck %s --check-prefix=X86WINPRMTD

// RUN: %clang_cc1 -triple=avr-unknown-unknown -mdouble=32 \
// RUN: -complex-range=promoted -emit-llvm -o - %s \
// RUN: | FileCheck %s --check-prefix=AVRFP32

// RUN: %clang_cc1 -triple=avr-unknown-unknown -mdouble=64 \
// RUN: -complex-range=promoted -emit-llvm -o - %s \
// RUN: | FileCheck %s --check-prefix=AVRFP64
```

https://github.com/llvm/llvm-project/pull/81514