This fixes LTO profiledbootstrap. tracer tail-duplicates loop
headers; that is not profitable and it makes loops have multiple
entries which inhibits further optimization. The following
patch cures that.
LTO profiledbootstrapped on x86_64-unknown-linux-gnu, regular
testing in progress.
Richard
The following patch fixes PR52808 - the issue is as in the
duplicate_block fixme comment - if we are destroying a loop
by means of adding another entry we have to do that. Thus
tracer needs to cleanup the cfg after it finished (a good idea
anyway). And jump threading needs to tell cfg manipulati
