https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121183
Bug ID: 121183
Summary: extra sign extend in some cases
Product: gcc
Version: 14.2.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Take:
```
long long f(long long l){
if(l>1000) return l;
if(l<-1000) return l;
int t = l;
return t + 2;
}
long long f1(long long l){
if(l>1000) return l;
if(l<-1000) return l;
long long t = l;
return t + 2;
}
```
GCC knows that l is [-1000,1000] when there is a cast to int and then there is
an addition to 2 since that does not cause an overflow the addition could be
done in long long instead. So basically f and f1 should produce the same code.
This could in theory happen with induction variables but I have not seen this
in real code yet.
