Please note that llvm-upgrade is undergoing major surgery. Related issues are:

bug 645 and bug 1082

These will be resolved in the next week or so.

The recent re-write of llvm-upgrade should have fixed this but. It no longer
gives the error and produces this output for the attached test case:

; ModuleID = ''
%RPyString = type { i32, %arraytype_Char_1 }
%arraytype_Char_1 = type { i32, [0 x i8] }
%structtype_rpy_string = type { i32, %arraytype_Char_1 }

implementation ; Functions:

define i8* @​RPyString_AsString(%RPyString* %structstring) {
%source1ptr = getelementptr %RPyString* %structstring, i32 0, i32 1, i32
1 ; <[0 x i8]> [#uses=1]
%source1 = bitcast [0 x i8] %source1ptr to i8* ; <i8*> [#uses=1]
ret i8* %source1
}