On 05/03/2016 11:26 PM, David Edelsohn wrote:
Optimizations enabled by default at -O2 should show an overall net
benefit -- that is the general justification that we have used in the
past. I request that this change be reverted until more compelling
evidence of benefit is presented.
Shrug. Done. I was going to look at adding some more smarts to it to
clean up after the register allocator; I guess I shan't bother.
I must say I find the argumentation about the fallout not compelling.
It's a normal consequence of development work, and by enabling it at
-O2, we have found:
* a Linux kernel bug
* a rs6000 testsuite bug
* some i386.md issues that can cause performance problems
* and a compare-debug problem in regrename itself.
All of these are _good_ things. If we don't want to run into such issues
we'll have to cease all development work.
I'll still submit final versions of the fixes for the i386 and
compare-debug issues.
Bernd
