https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116136
Richard Sandiford <rsandifo at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |rsandifo at gcc dot gnu.org
--- Comment #2 from Richard Sandiford <rsandifo at gcc dot gnu.org> ---
I was curious how far back this went, but it seems to be present in the
original combine.c commit:
/* Changing mode twice with SUBREG => just change it once,
or not at all if changing back to starting mode. */
if (GET_CODE (SUBREG_REG (x)) == SUBREG)
{
if (mode == GET_MODE (SUBREG_REG (SUBREG_REG (x)))
&& SUBREG_WORD (x) == 0 && SUBREG_WORD (SUBREG_REG (x)) == 0)
return SUBREG_REG (SUBREG_REG (x));
Kind-of amazed that this went undetected so long, especially since multiword
big-endian values were much more common back in the day.
