Hi Roman, On Wed, 16 May 2012, Роман Саженков wrote: > It seems like I've found an inaccuracy in GCC 4.7.0 documentation. It is > about -fdefer-pop optimization option. The point is that this option is > mentioned in the list of optimization flags which -O1 turns on (Chapter > 3: GCC Command Options, part 3.10 Options That Control Optimization, > page 107/766 of http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc.pdf), but > there are no any other allusions to -fdefer-pop in the document, even in > 3.1 Option Summary, where it is expected to be. There is no explanation > of what this flag does in HTML version of the document too (here > [http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Optimize-Options.html#Optimize-Options] > > and here > [http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Option-Summary.html#Option-Summary]). > > I'm guessing that this flag is not further supported by GCC, or not yet > implemented.
thank you for reporting this, and sorry for getting back to you with nearly three years delay. You did find a real issue in that -fdefer-pop is listed as being activated by the -O option, but not anywhere else in the documentation. However, there is actually code to support this option, specifically in gcc/common.opt and gcc/calls.c: calls.c: else if (flag_defer_pop && inhibit_defer_pop == 0 common.opt: Common Report Var(flag_defer_pop) Optimization I filed a bug report to track this, and hopefully one of the technical experts is going to address it: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65703 Gerald
