[Bug optimization/14706] New: [tree-ssa] range checks should be merged.

[kazu at cs dot umass dot edu]

We know that fold() can fold (a > 10 && a < 20) into
((unsigned int) (a - 11) <= 8).

We should also be able to optimize foo() in a similar way.
Note that bar() can be implemented using a conditional move and no jump.

int g;

void
foo (int a)
{
  if (a > 10)
    if (a < 20)
      g = 0;
}

void
bar (int a)
{
  if ((unsigned int) (a - 11) <= 8)
    g = 0;
}

-- 
           Summary: [tree-ssa] range checks should be merged.
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Keywords: pessimizes-code
          Severity: enhancement
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14706