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reload: Adjust comment in find_reloads about subset, not intersection

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gcc:
	* reload.cc (find_reloads): Align comment with code where
	considering the intersection of register classes then tweaking the
	regclass for the current alternative or rejecting it.
This commit is contained in:
Hans-Peter Nilsson 2022-03-26 05:31:22 +01:00
parent 81faedaa8e
commit 75d1c8fea9
1 changed files with 9 additions and 6 deletions
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15
gcc/reload.cc
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@ -3635,9 +3635,11 @@ find_reloads (rtx_insn *insn, int replace, int ind_levels, int live_known,
a hard reg and this alternative accepts some
register, see if the class that we want is a subset
of the preferred class for this register. If not,
but it intersects that class, use the preferred class
instead. If it does not intersect the preferred
class, show that usage of this alternative should be
but it intersects that class, we'd like to use the
intersection, but the best we can do is to use the
preferred class, if it is instead a subset of the
class we want in this alternative. If we can't use
it, show that usage of this alternative should be
discouraged; it will be discouraged more still if the
register is `preferred or nothing'. We do this
because it increases the chance of reusing our spill
@ -3664,9 +3666,10 @@ find_reloads (rtx_insn *insn, int replace, int ind_levels, int live_known,
if (! reg_class_subset_p (this_alternative[i],
preferred_class[i]))
{
/* Since we don't have a way of forming the intersection,
we just do something special if the preferred class
is a subset of the class we have; that's the most
/* Since we don't have a way of forming a register
class for the intersection, we just do
something special if the preferred class is a
subset of the class we have; that's the most
common case anyway. */
if (reg_class_subset_p (preferred_class[i],
this_alternative[i]))