On Tue, Apr 13, 2010 at 05:11, charfi asma <charfiasma@xxxxxxxx> wrote: > 1. Are IPA performed in High gimple (before SSA convertion) or In SSA form just like other intraprocedural optimization? > If they are performed before SSA did this implementation has an impact on the memory consumption, since SSA is less compact than High Gimple. In SSA form, just like other intraprocedural optimizations. > 2. In -function-at-a-time, each function is compiled immediately after parsing its body. however, in unit-at-a-time, all functions are parsed first then analyzed and compiled. > > unit-at-time is a new compilation scheme that was added to perfrom IPA, cause it is impossible to implement IPA in function-at-time. why we can not do it ? Because in function-at-a-time, every function is lowered down to final assembly. By then, it is too late to do any analysis/transformation. The compiler operates in unit-at-a-time by default in recent versions. Diego.
