------- Additional Comments From uttamp at us dot ibm dot com 2005-05-26 18:23
-------
(In reply to comment #0)
> test case:
> $ cat bug1.c
> void f1()
> {
> long bit=0, exponent;
> exponent = -exponent;
> for (bit = 1; exponent; bit <<= 1)
> if (exponent & bit)
> exponent ^= bit;
> }
>
> # Compilation parameters
> $ gcc -c -O3 -m64 bug1,c
>
> gcc gives internal compiler error on Powerpc platform.
>
> bug1.c: In function ‘f1’:
> bug1.c:8: error: could not split insn
> (insn:TI 13 11 14 (parallel [
> (set (reg:CC 75 7 [125])
> (compare:CC (neg:DI (reg/v:DI 0 0 [orig:119 exponent ] [119]))
> (const_int 0 [0x0])))
> (set (reg/v:DI 0 0 [orig:118 exponent.1 ] [118])
> (neg:DI (reg/v:DI 0 0 [orig:119 exponent ] [119])))
> ]) 76 {*rs6000.md:1653} (nil)
> (nil))
> bug1.c:8: internal compiler error: in final_scan_insn, at final.c:2419
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <URL:http://gcc.gnu.org/bugs.html> for instructions.
>
> Compiler works with all other optimization flags.
I didn't mean to mislead anybody with my earlier comment. But actually compiler
fails with all optimization flags (-O2 and above). And a test case also has one
change to make it more generic type. In the original test case 'exponent' was
just a local and unitialized variable.
void f1(long exponent)
{
long bit=0;
exponent = -exponent;
for (bit = 1; exponent; bit <<= 1)
if (exponent & bit)
exponent ^= bit;
}
>
> After doing reghunt I found a patch, which may not necessarily have caused the
> above failure but compiler started failing after application of this patch,
>
> http://gcc.gnu.org/ml/gcc-cvs/2005-05/msg00232.html
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21761
