[clang] [HLSL] Implement the `ldexp` intrinsic (PR #138182)

[Farzon Lotfi via cfe-commits]

farzonl wrote:

Might be worth looking at usages of ldexp in  https://github.com/microsoft/DirectX-Graphics-Samples/tree/master/MiniEngine/Core/Shaders/PixelPacking_RGBE.hlsli specically lines 52 and 79 and make sure their is no ambiguous cases to answer @V-FEXrt question here: https://github.com/llvm/wg-hlsl/issues/264#issuecomment-2845201428

Then start looking at
https://github.com/llvm/wg-hlsl/issues/242 (https://github.com/llvm-beanz/offload-test-suite/issues/95)




https://github.com/llvm/llvm-project/pull/138182