[LLVMbugs] [Bug 2279] New: Conformance problems with pp expressions

bugzilla-daemon at cs.uiuc.edu bugzilla-daemon at cs.uiuc.edu
Sat May 3 18:29:34 PDT 2008


           Summary: Conformance problems with pp expressions
           Product: clang
           Version: unspecified
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: preprocessor
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: neil at daikokuya.co.uk
                CC: llvmbugs at cs.uiuc.edu

These are conformance problems I'm aware of regarding PP expressions.  If you
need a testcase I can provide, but they should be obvious from the

a) Comma subexpressions are permitted in C99 as long as they are unevaluated. 
Clang rejects them, which is correct behaviour for C90 but not C99 (see 6.6).
b) Clang doesn't follow the grammar for the 2nd operand of the conditional
c) Clang doesn't follow the rules for the signedness of the result of the shift
operators (no UAC).
d) Clang seems to have issues with unevaluated subexpressions.  Here are two

#if 0 ? 1/0: 2

#if 1 || 1/0

Configure bugmail: http://llvm.org/bugs/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.

More information about the llvm-bugs mailing list