Finding MAC instructions

Hi,

for a project I want to extend our comiler (more accurately, our
code generator) for a DSP by generating optimized code using
DSP-specific instructions like the MAC (multiply accumulte).

Our compiler framework consists of a high- and a low-level
intermediate represetation and translates C code.

Could you give me any hints how potential high-level language
candidates (in C) can be recognized (and realized in assembler
by the efficient MAC instructions).
Do I need to take information from our low-level IR into account
or does it suffice to consider code in the target-specific
(assembly-like) low-level IR?

I appreciate your help since I could not find any information
about this specific topic on the internet.

Best regards,
Christian

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