[LLVMbugs] [Bug 23976] New: Cast linear array to rectangular array compilation failure

[bugzilla-daemon at llvm.org]

https://llvm.org/bugs/show_bug.cgi?id=23976

            Bug ID: 23976
           Summary: Cast linear array to rectangular array compilation
                    failure
           Product: clang
           Version: 3.5
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++
          Assignee: unassignedclangbugs at nondot.org
          Reporter: jhart.public at gmail.com
                CC: dgregor at apple.com, llvmbugs at cs.uiuc.edu
    Classification: Unclassified

Reinterpreting a dynamically allocated N*M block of int as an NxM rectangular
array fails with clang++ 3.5, producing a spurious error message:

test.cpp:5:8: error: non-const lvalue reference to type 'int [n][m]' cannot
bind to a value of unrelated type 'int [n][m]'

Code compiles successfully on the same platform with gcc 4.9.


test case:

#include <cassert>

void f(int *mem, int n, int m)
{
        int (&array)[n][m] = *reinterpret_cast<int (*)[n][m]>(mem);

        assert((void*)&array == (void*)mem);
        assert(sizeof(array) == (n*m)*sizeof(int));
}

int main() {
        const int N = 3;
        const int M = 4;
        int *p = new int[N*M];
        f(p, N, M);
        delete[] p;
}


clang++ -v output:
Debian clang version 3.5.2-1 (tags/RELEASE_352/final) (based on LLVM 3.5.2)
Target: x86_64-pc-linux-gnu

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