https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96245
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2020-07-20
CC| |marxin at gcc dot gnu.org
Keywords| |missed-optimization
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
switch-conversion(?), it does look like a very special case. Similar:
int y;
void f(int x)
{
switch (x)
{
case 0:
y = 0;
break;
case 1:
y = 1;
break;
...
converting to if (...) y = x; or more general to x + CST. The store
commoning patch should in this case sink this to y = PHI<...> where
switch-conversion would convert the PHI<...>. For the putchar case
there's nothing "commoming" the call (the same code doing the store
sinking could also sink calls if we want that). Not sure if
switch-conversion itself would want to do this (profitability increases
if we can eliminate the PHI<> by arithmetics).
