[llvm-bugs] [Bug 45966] New: Failure to optimize result of function in switch optimally

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45966

            Bug ID: 45966
           Summary: Failure to optimize result of function in switch
                    optimally
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: gabravier at gmail.com
                CC: llvm-bugs at lists.llvm.org

inline int check(int i, int j)
{
    if (i == j)
        return 0;
    else if (i > j)
        return 1;
    else
        return 2;
}

int foo(int i, int j)
{
    switch (check(i, j))
    {
        case 0:
            return i + j;
        case 1:
            return i;
        case 2:
            return j;
    }
}

`foo` can be optimized to `return (i == j) ? (i + j) : ((i > j) ? i : j)`. This
transformation is done by GCC, but not by LLVM.

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