"Paul Koning" <paulkon...@comcast.net> wrote: >> On Jan 9, 2023, at 7:20 AM, Stefan Kanthak <stefan.kant...@nexgo.de> wrote: >> >> Hi, >> >> GCC (and other C compilers too) support the widening multiplication >> of i386/AMD64 processors, but DON'T support their narrowing division: > > I wonder if this changed in the recent past. > I have a pattern for this type of thing in pdp11.md: [...] > and I'm pretty sure this worked at some point in the past.
Unfortunately the C standard defines that the smaller operand (of lesser conversion rank), here divisor, has to undergo a conversion to the "real common type", i.e. the broader operand (of higher conversion rank), here dividend. Unless the information about promotion/conversion is handed over to the code generator it can't apply such patterns -- as demonstrated by the demo code. regards Stefan
