Remove an instruction through Dead Code Elimination pass of llvm

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1

My pass in LLVM generates an IR like this
%5 = icmp eq i32 %4, 0
%7 = or i1 %5, %5
;. . .
Since the ‘or’ instruction is actually not needed(dead code), I replaced all occurences of %7 with %5.
Now, the ‘or’ instruction should get deleted. How can I call Dead Code Elimination pass of LLVM from my pass or is there any method to remove that ‘or’ instruction?

Thank you.
Adarsh Konchady

2

Hi Adarsh,

3

Adarsh,

Usually the pass should handle such simple and clear clean ups itself. If you grep for Inst->eraseFromParent() in source based then you'll see that many transformations are doing it immediately after they know that they have replaced all occurrences of %7.