[PATCH] IR: Make the X / undef -> undef fold match the comment
Sanjoy Das via llvm-commits
llvm-commits at lists.llvm.org
Wed Feb 24 16:59:54 PST 2016
Looks like the original code just had a typo; and after your change
both the control flow and comments sync up to what I'd have expected.
On Wed, Feb 24, 2016 at 4:46 PM, Justin Bogner <mail at justinbogner.com> wrote:
> The constant folding for sdiv and udiv has a big discrepancy between the
> comments and the code, which looks like a typo. Currently, we're folding
> X / undef pretty inconsistently:
> 0 / undef -> undef
> C / undef -> 0
> undef / undef -> 0
> Whereas the comments state we do X / undef -> undef. The logic that
> returns zero is actually commented as doing undef / X -> 0, despite that
> the LHS isn't undef in many of the cases that hit it.
> Is this okay to commit, or is it the comments that should be updated to
> match the code instead?
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