[Bug middle-end/66313] Unsafe factorization of a*b+a*c

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66313

--- Comment #19 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 41441
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41441&action=edit
patch

Patch I am testing, I finally managed to convince tailrecursion optimization to
handle the case in gcc.dg/tree-ssa/tailrecursion-6.c after the fix to the
folding.

If testing goes well I'll commit this to trunk.