Need help for a net target

[Michael_fogel]

Hello

For my diploma thesis I have to implement a new back-end for GCC.
The microcontroller is based on an FPGA and was developed one year ago. 
Only an Assembler is available and now my university lecturer wants an C 
compiler too. I decided to use GCC in version 4.2.1 as basis for the new 
compiler.

I started with an new target, defined the mandatory target macros and 
implemented the instruction patterns.

After i few tries i was able to compile my first file. Now I try to make 
the optimization working, but there is a problem i can not solve.
Compiling the following code with activated optimization comes up with 
an error message.


#define RAM_ADDRESS 0
#define SERIAL_OFFSET 800

void ReadSerialNumber(void) {
 int  SerialNumber, c;
 char *s;
  
 SerialNumber   =   0;                
 s   =   (char*)(RAM_ADDRESS + SERIAL_OFFSET);
 while ((c =  *s - '0') <= 9){         
     SerialNumber = 10*SerialNumber + c;       
     s++;          
 }

 // ...
}

test.c: In function 'ReadSerialNumber':
test.c:40: internal compiler error: in create_mem_ref, at 
tree-ssa-address.c:677
Please submit a full bug report,

adding an volatile

volatile char *s;


fixes it but I think the real problem is somewhere else.


thanks for you help

best regards
Michael Fogel