On Tue, Oct 09, 2012 at 08:23:27AM -0700, Richard Henderson wrote: > On 10/09/2012 08:13 AM, Aurelien Jarno wrote: > >> > It also prefers > >> > > >> > add r, r, c > >> > over > >> > add r, c, r > >> > > >> > when both inputs are known constants. This doesn't matter for true add, > >> > as > >> > we will fully constant fold that. But it matters for a follow-on patch > >> > using > >> > this routine for add2 which may not be fully foldable. > ... > > Does this sum += and -= actually generates better code than the previous > > one? It's not something obvious to read (fortunately there is the > > comment for helping), so if it doesn't bring any optimization, it's > > better to keep the previous form. > > Yes. See the comment within the log above.
I am not talking about the code generated by TCG, but rather by the code generated by GCC. Does using sum += and sum -= brings a gain to compare to the equivalent if function? -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net
