[llvm-commits] [PATCH] Simplify negated bit test

[Jakub Staszak]

On Dec 10, 2012, at 9:58 PM, David Majnemer <david.majnemer at gmail.com> wrote:

> 
> 2. It doesn't have to be 1 which is shifted. It works with any power-of-two value (you can use m_Power2 pattern).
> I was under the impression that m_Power2 does not handle values generated from shl instructions.
> 
> Further, it seems that LLVM already turns !!(~A & C) into !(A & C) where C is a constant and a power of 2. Should I add such a transform anyway?
>  

What I meant was you should m_Power2 the constant value itself. So it should work also with (2 << x), (4 << x), etc.

- Kuba
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