http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51030
Bug #: 51030 Summary: PHI opt does not handle value-replacement with a transfer function Classification: Unclassified Product: gcc Version: 4.7.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: enhancement Priority: P3 Component: tree-optimization AssignedTo: unassig...@gcc.gnu.org ReportedBy: rgue...@gcc.gnu.org int f(int i) { if (i) return i+2; return 2; } struct C { int i; }; int *g(struct C *p) { if (p) return &p->i; return (int *)0; } both cases can be optimized to return i + 2 or &p->i, respectively. Currently it only handles int f(int i) { if (i != 1) return i; return 1; }