[Bug tree-optimization/64992] More optimize opportunity

[jakub at gcc dot gnu.org]

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

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Well, b is not volatile.

The difference is that 2U * (1 == c) we expand during gimplification as
if (1 == c)
  iftmp = 2;
else
  iftmp = 0;
while b * (1 == c) is expanded as multiplication of the EQ_EXPR result and
nothing at the tree level changes that afterwards.  Perhaps something for
match.pd, though not sure if such an transformation is always a win.