On 03/09/15 03:53, Steven Bosscher wrote:
On Wed, Mar 4, 2015 at 12:09 PM, Alex Velenko wrote:
For example, in arm testcase pr43920-2.c, CSE previously decided not to put
an "obvious" note on insn 9, as set value was the same as note value.
At the same time, other insns set up as -1 were set up through a register
and did get a note:
...which is the point of the REG_EQUAL notes. In insn 8 there is a
REG_EQUAL note to show that the value of r111 is known. In insn 9 the
known value is, well, known from SET_SRC so there is no need for a
REG_EQUAL note. Adding REG_EQUAL notes in such cases is just wasteful.
RIght. I'd rather look into why later passes aren't discovering
whatever equivalences are important rather than adding the redundant notes.
Regardless, I think this is a gcc-6 issue, so I'm not likely to look at
it in the immediate future.
jeff
