------- Comment #21 from ebotcazou at gcc dot gnu dot org 2010-01-07 07:39 ------- > Because at the point of propagation, propagated constant _is_ equal to > whatever REG_EQUAL says. Removing this note at the point of propagation > would IMO disable much more optimization opportunities.
What kind of opportunities exactly? The insn is more precise that the note. > BTW: This fixup happens in very rare occasions. Although the loop looks scary, > it usually processes very small BBs (I didn't found the case where more than > one assignment was moved at the top of the test BB. Yes, but removing REG_EQUAL notes pointing to constants seems a bad idea. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42511
