+2008-01-21 DJ Delorie <dj@redhat.com>
+
+ * doc/tm.texi (HARD_REGNO_NREGS): Note that this macro must not
+ return zero.
+
2008-01-21 Richard Guenther <rguenther@suse.de>
PR middle-end/34856
@defmac HARD_REGNO_NREGS (@var{regno}, @var{mode})
A C expression for the number of consecutive hard registers, starting
at register number @var{regno}, required to hold a value of mode
-@var{mode}.
+@var{mode}. This macro must never return zero, even if a register
+cannot hold the requested mode - indicate that with HARD_REGNO_MODE_OK
+and/or CANNOT_CHANGE_MODE_CLASS instead.
On a machine where all registers are exactly one word, a suitable
definition of this macro is