Bug 63277

I extracted the buggy function and all of it's dependent garbage and was able 
to make it continue failing with a much smaller file (like 300 lines vs. 300 
files).  I was able to isolate the problem to lines of the form:

    stats->testVector.tifport0 = (INT16)(p->p0 & port0Mask);

where:
  stats is a large structure including a structure named testVector that has a 
short named tifport0,
  INT16 is typedef to be a short,
  p is a structure consisting of six int (p0-p5),
  port0Mask is also an int.

If you managed to cut it down into a 300 line testcase, then please preprocess
it (gcc -E) and attach here. Without testcase there is nothing I can do about this.

Here's the file that fails.  I've chopped it down about as much as possible to 
still see the failure.  I also included the Makefile.  It doesn't fail when I 
get rid of the -O4, and it also doesn't seem to fail when I get rid of the 
CM_PORTTYPE structure and just use a plain INT32 for p0.

The Makefile is the following:
// Begin Makefile
OPTIMIZE_LEVEL = -O4

BASEOPCFLAGS = -c  $(OPTIMIZE_LEVEL) -Iinclude
COMPILE = g++

CFLAGS = -c -g `gtk-config --cflags` 
LFLAGS = `gtk-config --libs` 

texture_short.o:        texture_short.cc 
                        $(COMPILE) $(BASEOPCFLAGS) texture_short.cc -o texture_s
hort.o

clean:
        rm -f texture_short.o
// End Makefile

The C++ code is the following:
// Begin texture_short.cc
typedef unsigned char   BYTE;
typedef short           INT16;
typedef int             INT32;
typedef double          REAL;

typedef struct  {
        INT32   p0;             // This was much bigger
} CM_PORTTYPE;

typedef struct {
        INT16   tp0;
        BYTE    tpV;
        BYTE    bVal;
} TEST_VECTOR;

typedef struct {
        BYTE    CMOutEn;
        BYTE    CMOutEn2;
        TEST_VECTOR testVector;
} STATS;

void
loadIRPixelPorts(CM_PORTTYPE *p, REAL p0, INT32 irMask, STATS *stats)
{
        REAL p0Mult = 65536.0;          // 16 bits unsigned
        REAL p0IRMult = 4096.0; // 16 bits unsigned 3.12
        INT32 p0Mask = 0x0ffff;         // 12 bits
        INT32 p0IR =  irMask & 1;

        if (p0IR) p->p0 = (INT32) (p0 * p0IRMult);
        else p->p0 = (INT32)(p0 * p0Mult);

        if (stats->CMOutEn || stats->CMOutEn2) {

                stats->testVector.tpV = stats->testVector.bVal;
// The compile problem is the next line
                stats->testVector.tp0 = (INT16)(p->p0 & p0Mask);
        }
}
// End texture_short.cc

Fixed in gcc-2.96-110.