[LLVMdev] Missed constant replacement opportunity with llvm.assume?

[Josh Klontz]

Opened a bug with a minimum reproducing example:

https://llvm.org/bugs/show_bug.cgi?id=23055

It seems to me the issue is that InstCombiner successfully simplifies
return values when they can be proven constant, but misses the same
optimization opportunity for store values.

v/r,
Josh

On Fri, Mar 27, 2015 at 11:29 AM, Josh Klontz <josh.klontz at gmail.com> wrote:

> As of ToT it seems that even the simplest cases of assumes involving
> equality between an instruction and a constant don't cause an instruction
> RAUW constant.
>
> In the attached example, %channels is assumed to be 3, leading to a missed
> optimization opportunity with %src_c.
>
> Am I overlooking something that would cause this optimization to be
> invalid?
>
> v/r,
> Josh
>
>
>
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