[Bug middle-end/46923] New: [trans-mem] thread-local memory variable not properly logged

[rth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46923

           Summary: [trans-mem] thread-local memory variable not properly
                    logged
           Product: gcc
           Version: trans-mem
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: r...@gcc.gnu.org


extern void baz(int);
int y;
void foo(volatile int x)
{
  __transaction {
    x += y;
    y++;
  }
  baz(x);
}

Ignore the fact that volatile is not really compatible with
transactional memory; it is used here only to force the 
compiler to put X into memory without having to generate a
much more complex test case.

It currently compiles to 

        call    _ITM_beginTransaction
        movl    12(%rsp), %ebx
        movl    $y, %edi
        call    _ITM_RfWU4
        leal    1(%rax), %esi
        movl    $y, %edi
        leal    (%rax,%rbx), %ebx
        movl    %ebx, 12(%rsp)
        call    _ITM_WaWU4
        call    _ITM_commitTransaction

Note that X, at %rbp+12, is written back to memory and is
not logged.  If the either the write or commit functions
have to restart the transaction, we will produce the wrong
answer.