Michael_fogel writes:
> 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.
Are you telling us that you have got all this way with gcc, but you
have *never* debugged it with gdb? If so, this is the time to learn.
Run "gcc -v" to see te args passed to cc1, break out gdb, and start
debugging the ICE.
A clue:
/* Verify that the address is in the simplest possible shape
(only a register). If we cannot create such a memory reference,
something is really wrong. */
gcc_assert (parts.symbol == NULL_TREE);
gcc_assert (parts.index == NULL_TREE);
gcc_assert (!parts.step || integer_onep (parts.step));
gcc_assert (!parts.offset || integer_zerop (parts.offset));
gcc_unreachable ();
Andrew.
