Paul Eggert wrote:
But so far, benchmark scores are the only scores given by the people
who oppose having -O2 imply -fwrapv.
And you expect real-world results will be different because...?
You say you doubt it affects performance. Based on what? Facts
please, not guesses and hand-waiving...
The burden of proof ought to be on the guys proposing -O2
optimizations that break longstanding code, not on the skeptics.
IMHO the burden of proof should be on the people who are surprised that
interesting things happen when they write in a language that isn't C and
then try to pass it through a C compiler.
Has an example of code that actually breaks with a new gcc but not an
old one been posted in this thread yet? With -fstrict-aliasing we at
least had examples of code that really broke with a new optimization
before we disabled it (in the compiler, not in autoconf, mind you).
Code got fixed, -fstrict-aliasing got enabled a release later, everyone
moved on.
Bernd
