On Wed, Apr 18, 2012 at 4:15 AM, Maxim Kuvyrkov <ma...@codesourcery.com> wrote: > Steven, > J"orn, > > I am looking into fixing performance regression on EEMBC's bitmnp01, and a > version of your combined patch attached to PR38785 still works very well. > Would you mind me getting it through upstream review, or are there any issues > with contributing this patch to GCC mainline? > > We (CodeSourcery/Mentor) were carrying this patch in our toolchains since GCC > 4.4, and it didn't show any performance or correctness problems on x86, ARM, > MIPS, and other architectures. It also reliably fixes bitmnp01 regression, > which is still present in current mainline. > > I have tested this patch on recent mainline on i686-linux-gnu with no > regressions. Unless I hear from you to the contrary, I will push this patch > for upstream review and, hopefully, get it checked in. > > Previous discussion of this patch is at > http://gcc.gnu.org/ml/gcc-patches/2009-03/msg00250.html
The addition of -ftree-pre-partial-partial is ok if you change its name to -ftree-partial-pre and add documentation to invoke.texi. + /* Assuming the expression is 50% anticipatable, we have + to multiply the number of insertions needed by two for a cost + comparison. */ why assume 50% anticipatibility if you can compute the exact anticipatibility? + if (!optimize_function_for_speed_p (cfun) please look at how I changed regular PRE to look at whether we want to optimize the path which has the redundancy for speed via optimize_edge_for_speed_p. The same surgerly should be applied to PPRE. Thanks, Richard. > Thank you, > > -- > Maxim Kuvyrkov > CodeSourcery / Mentor Graphics >
