[Bug tree-optimization/64992] More optimize opportunity

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64992

Marc Glisse <glisse at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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             Status|WAITING                     |NEW

--- Comment #5 from Marc Glisse <glisse at gcc dot gnu.org> ---
We do not sink the code that computes d into the branch c==-1. If we did, the
second comparison would simplify to a constant. VRP is not clever enough to
"backport" new assertions to already computed values.

We could also simplify N*x==0 to x==0 even for unsigned when VRP information
tells us that overflow/wrap cannot happen (here N is 2 and x is in [0,1]).