[Bug middle-end/28283] SuperH: Very unoptimal code generated for 64-bit ints

[roger at eyesopen dot com]

------- Comment #2 from roger at eyesopen dot com  2006-07-06 19:17 -------
Investigating...  I suspect that the SH backend's rtx_costs are parameterized
incorrectly, such that a 64-bit shift by the constant 32, looks to be at least
32 times more expensive than a 64-bit addition.  The middle-end then uses
these numbers to select the appropriate code sequence to generate.  Combine
also doesn't both cleaning this up because it also the same invalid rtx_costs,
and discovers than combining additions into shifts doesn't appear to be a win
on this target.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28283