[llvm-dev] How to add a pass to do zero check for all DIV instructions

[Jeremy Lakeman via llvm-dev]

If you write a pass that runs against IR, other optimisations may be able
to prove when the value is zero and remove the test.

On 13 November 2018 at 13:44, 石博文 via llvm-dev <llvm-dev at lists.llvm.org>
wrote:

> Hi. I'm a new learner for LLVM. I want to write a pass to add some custom
> instructions to check zero for DIV. （X86-64 architecture）
>
> before:
> ```
> IDIV EBX
> ```
>
> after:
> ```
> TEST EBX, EBX
> JNZ L1
> MOV EBX, 1
> L1:
> IDIV EBX
> ```
>
> I think it's need to modify some code in instruction generate pass, but I
> don't know where is the relation files.
>
> --
> *B. W. Shek*
>
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