Global register variable definition is removed as dead code

[Ian Lance Taylor]

Pitchumani Sivanupandi <pitchumani.s@hotmail.com> writes:

> Consider the following test case:
> // gcc-4.6.1// option: -O1
> register void  *ptr asm("rbx") ;
> void testfn1(void* func){  ptr = func;  // removed as dead code  goto *ptr;}
> When compiling with O1 option, 'ptr = func' definition is removed as dead code. But ref[1] says it should not be deleted even if it appears to be dead.
> In dead code elimination (gcc/dce.c), the register definition is not checked for "global register variable".
> Is gcc's behaviour is correct?
> ref1: http://gcc.gnu.org/onlinedocs/gcc/Global-Reg-Vars.html

That is definitely a bug.  Please file a bug report as described at
http://gcc.gnu.org/bugs .  Thanks.

Ian