[Bug optimization/13000] New: Using -Ox cannot detect missing return statement in a function

["cheng at powertv dot com" <gcc-bugzilla at gcc dot gnu dot org>]

In the following contrived code snippet, gcc 2.953 will not complain about the 
function not returning a value despite its function signature says so when 
compiling with optimizations enabled (e.g. -O1 or -O2).  Disabling 
optimizations with -O0 will enable the compiler to display an appropriate error 
message.  This problem appears in both C and C++ test code.


typedef int ui32;

static ui32 AddPrimitiveDvrResource(ui32 hSession, ui32 *pSessNode,
									
	void *pvResourceDescriptor, ui32 dwSize);

static ui32 AddPrimitiveDvrResource(ui32 hSession, ui32 *pSessNode,
									
	void *pvResourceDescriptor, ui32 dwSize)
{
	ui32 rc;

	if (dwSize != 32)
	{
		rc = 0;
	}
	else
	{
		// set the DVR ID in the session node even if subsequent steps 
fail
		
		if (dwSize) 
		{
			rc = dwSize;
		}
		else
		{
			if (!pSessNode)
			{
				rc = 2;
			}
			else
			{
				ui32 dwTranscryptorAvrID = 0;
	
				if (rc = dwTranscryptorAvrID)
				{
					dwTranscryptorAvrID;
				}
				else
				{
					ui32 dk;

					if (rc = 16)
					{
						dk = rc;
					}
					else
					{
						if (dk) 
						{
							rc = 1;
						}
						else
						{
							rc = 0;
						}
					}
				}
			}
		}
	}
}

int main(int argc, char **argv)
{
	int result = AddPrimitiveDvrResource(0,0,0,0);

	return 0;
}

-- 
           Summary: Using -Ox cannot detect missing return statement in a
                    function
           Product: gcc
           Version: 2.95.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: cheng at powertv dot com
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13000