http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51795
--- Comment #9 from Marc Glisse <marc.glisse at normalesup dot org> 2012-01-27 12:53:38 UTC --- (In reply to comment #6) > Marc, can you see a "quick and dirty" (ie, suited for 4.7 too) way to fix > this? Note that I am not a specialist. 1) add an assertion "not implemented yet, try a smaller constant" 2) if you know how to multiply by small a, you can decompose large a into a1*a2+a3 and perform the operations separately (variants might make sense, including using powers of 2 and also splitting x) 3) do the double precision operation. longlong.h contains generic code for that (but beware UDIV_NEEDS_NORMALIZATION). About comment #7, if that's how you interpret it, it may be worth opening a DR. I believe the formula has to be interpreted with mathematical, arbitrary size integers (although of course you can optimize when m*m fits in _Tp).
