https://issues.dlang.org/show_bug.cgi?id=23568

          Issue ID: 23568
           Summary: Error: cannot implicitly convert expression 'a < b' of
                    type 'float4' to 'int4'
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: ibuclaw@gdcproject.org

For some reason, __vector(float) comparisons result in a float type, not a
mask.

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