On Sat, Aug 31, 2019 at 10:36:00AM +0930, Alan Modra wrote: > On Fri, Aug 30, 2019 at 11:35:11AM -0500, Segher Boessenkool wrote: > > > - unsigned HOST_WIDE_INT val = INTVAL (XEXP (addr, 1)); > > > - return val + 0x8000 >= 0x10000 - (TARGET_POWERPC64 ? 8 : 12); > > > + HOST_WIDE_INT val = INTVAL (XEXP (addr, 1)); > > > + HOST_WIDE_INT extra = TARGET_POWERPC64 ? 8 : 12; > > > > The 8 vs. 12 could use a comment (yes, I know it was there already). Do you > > know what this is about, why it is 8 and 12? > > "extra" here covers the increase in offset needed to access the memory > using multiple registers. For example, when loading a TImode mem to > gprs you will load at offset+0 and offset+8 when powerpc64, and > offset+0, offset+4, offset+8, and offset+12 when powerpc32.
Ah, so it is the size of the mode minus the size of the accesses done to get it... 16 - UNITS_PER_WORD may be a good way to express it? I don't see a way to say it that isn't still helped by a comment though. Thanks, Segher
