Global register variable definition is removed as dead code

Pitchumani Sivanupandi pitchumani.s@hotmail.com
Wed Dec 7 08:20:00 GMT 2011


Thanks.
A bug is filed in gcc-bugs. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51447
Thanks,Pitchumani.S

> > 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
 		 	   		   		 	   		  



More information about the Gcc-help mailing list