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Re: [PATCH] Add new target-hook truncated_to_mode


In http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00732.html, you wrote:

meant by these instructions complementing each other.  Or in other
words instead of:

narrowing SUBREG != TRUNCATE

we will now say:

widening SUBREG == SIGN_EXTEND

and try to derive the former property from the latter.  But overall I
do agree that it usually carries more information to say what
something _is_ than what it _is not_.

Actually, that is not an accurate description for the SH5. Although an SImode value in an integer register will be held sign-extended, that is not true of SImode values in floating point registers.

If you hold an SImode value in a floating point register and want to store it
sign-extended to memory, you have to do a sign-extending copy into an integer
register first (at least that is the most straightforward way to do it).




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