> Hi Honza,
>
> thanks for putting this together. Please find some notes below.
> Can you please take these plus the other bits of feedback you got
> and post an updated patch for a quick final check?
Thanks, here is updated patch!
Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
retrieving revision 1.72
diff -u -r1.72 changes.html
--- changes.html 25 Jan 2015 23:47:32 -0000 1.72
+++ changes.html 26 Jan 2015 06:10:15 -0000
@@ -35,6 +35,15 @@
<ul>
<li>Inter-procedural optimization improvements:
<ul>
+ <li>An Identical Code Folding (ICF) pass (controled via
+ <code>-fipa-icf</code>) has been added. Compared to the identical
+ code folding performed by the Gold linker this
+ pass does not require function sections. It also performs merging
+ before inlining so inter-procedural optimizations are aware of the
+ code re-use. On the other hand not all unifications performed
+ by a linker are doable by GCC which must honor
+ aliasing information. During link-time optimization of Firefox,
+ this pass unifies about 29000 functions that is 10% overall.</li>
<li>The devirtualization pass was significantly improved by adding
better support for speculative devirtualization and dynamic type
detection. About 50% of virtual calls in Firefox are speculatively
@@ -72,6 +81,11 @@
</ul></li>
<li>Feedback directed optimization improvements:
<ul>
+ <li>A new auto-FDO mode uses profiles collected by low overhead
+ profiling tools (perf) instead of more expensive program
+ instrumentation (via <code>-fprofile-generate</code>). SPEC2006
+ benchmarks on x86-64 improve by 4.7% with auto-FDO and by 7.3% with
+ traditional feedback directed optimization.
<li>Profile precision was improved in presence of C++ inline and extern
inline functions.</li>
<li>New <code>gcov-tool</code> to manipulate profiles.</li>
