possible gcse failure: not able to eliminate redundant loads

[Daniel Berlin]

On Thursday, December 12, 2002, at 05:42  PM, Richard Henderson wrote:

> On Thu, Dec 12, 2002 at 05:31:39PM -0500, David Edelsohn wrote:
>> 	I do not believe that the code exists, or if the code exists it is
>> disabled because it is broken in other ways, not alias.c.
>
> Yawn.
>
> 	int x;
> 	void foo()
> 	{
> 	  int i;
> 	  for (i = 0; i < 100; i++)
> 	    x += i;
> 	}
>
> foo:
>         movl    x, %eax
>         xorl    %edx, %edx
>         .p2align 4,,15
> .L6:
>         addl    %edx, %eax
>         incl    %edx
>         cmpl    $99, %edx
>         jle     .L6
>         movl    %eax, x
>         ret
>
> And from the .loop dump file,
>
> Loop from 10 to 31: 6 real insns.
> Continue at insn 23.
> Hoisted regno 62 r/w from (mem/f:SI (symbol_ref:SI ("x")) [2 x+0 S4 
> A32])
>
> Believe me now?

I remember someone saying that store motion should replace this, since 
it subsumes it.

>
> r~