On Mon, Jul 1, 2013 at 7:45 AM, Gene Smith <g...@chartertn.net> wrote: > I tried -Og optimization on a recent svn snapshot of 4.8 and don't see much > difference in the code compared to -O1. If anything, at least for one case, > -Og is actually less debuggable than -O1, e.g., for a simple buffer > selection like this: > > uint8_t* buffer; > > if (condx == true) > buffer = buf1; // buf1 is a static external buffer > else > buffer = buf2; // buf2 is a static external buffer > uint8_t foo = buffer[1]; > > With -O1 there is assembly code associated with each buffer assignment > statement. But with -Og there is no code under the first buffer = buf1 with > it all under the 2nd buffer = buf2. > > So, with -Og, when stepping through the code with condx true, it appears > that the wrong line is executing since the first buffer = buf1 has no code > and never occurs. Of course, the result is still correct and is actually > maybe more efficient or at least equal to the -O1 code, but there is no > improved debug experience in this case. > > In this case, the debug experience with -O1 is closer to -O0 than -Og is. > > Also with -Og, some variables are still optimized away like -O1 and higher, > but unlike -O0 where all variables are, of course, visible with the debugger > (gdb).
Can you please file a bugreport with a testcase that can be compiled and executed? Thanks, Richard. > -gene > > >
