[llvm-bugs] [Bug 45687] New: Failure to optimize away abs check based on known range of variable

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45687

            Bug ID: 45687
           Summary: Failure to optimize away abs check based on known
                    range of variable
           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

void g();

void f(int i)
{
    __builtin_assume(i >= -1 && i <= 1);

    if (abs(i) > 1)
        g();
}

This can all be optimized out. GCC does this transformation, LLVM does not.

Comparison here : https://godbolt.org/z/cLcicG

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