[LLVMbugs] [Bug 12145] New: codegen assert: Should not use decl without marking it used!

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=12145

             Bug #: 12145
           Summary: codegen assert: Should not use decl without marking it
                    used!
           Product: clang
           Version: unspecified
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: C++0x
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: richard-llvm at metafoo.co.uk
                CC: dgregor at apple.com, llvmbugs at cs.uiuc.edu,
                    sharparrow1 at yahoo.com
    Classification: Unclassified


The following code causes clang to assert in codegen:

  int a[20]; constexpr int *p = &a[5]; int n = *p;

clang-3.0: src/tools/clang/lib/CodeGen/CGExpr.cpp:1376: clang::CodeGen::LValue
clang::CodeGen::CodeGenFunction::EmitDeclRefLValue(const clang::DeclRefExpr *):
Assertion `(ND->isUsed(false) || !isa<VarDecl>(ND) ||
!E->getLocation().isValid()) && "Should not use decl without marking it used!"'
failed.

As far as I can see (please correct me if I'm wrong), we're right to not mark p
as used: it is usable in a constant expression and the lvalue-to-rvalue
conversion is immediately applied. Presumably codegen is simply not trying to
emit the value directly.

-- 
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.