[Bug debug/48853] [4.7 Regression] Wrong DWARF codegen when Pmode != ptr_mode

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48853

--- Comment #19 from H.J. Lu <hjl.tools at gmail dot com> 2011-05-06 22:43:36 UTC ---
(In reply to comment #17)
> loc_descriptor change in
> 
> http://gcc.gnu.org/ml/gcc-cvs/2011-04/msg01406.html
> 
> @@ -14469,7 +15018,10 @@
>       up an entire register.  For now, just assume that it is
>       legitimate to make the Dwarf info refer to the whole register which
>       contains the given subreg.  */
> -      loc_result = loc_descriptor (SUBREG_REG (rtl), mode, initialized);
> +      if (REG_P (SUBREG_REG (rtl)) && subreg_lowpart_p (rtl))
> +    loc_result = loc_descriptor (SUBREG_REG (rtl), mode, initialized);
> +      else
> +    goto do_default;
>        break;
> 
>      case REG:
> 
> doesn't handle:
> 
> Breakpoint 5, loc_descriptor (rtl=0x7ffff0b24c30, mode=SImode, 
>     initialized=VAR_INIT_STATUS_INITIALIZED)
>     at /export/gnu/import/git/gcc-x32/gcc/dwarf2out.c:15035
> 15035          if ((REG_P (SUBREG_REG (rtl))
> (gdb) call debug_rtx (rtl)
> (subreg:SI (symbol_ref:DI ("a") [flags 0x2] <var_decl 0x7ffff0a9c500 a>) 0)
> (gdb) 
> 

Also

Breakpoint 5, loc_descriptor (rtl=0x7ffff086be88, mode=SImode, 
    initialized=VAR_INIT_STATUS_INITIALIZED)
    at /export/gnu/import/git/gcc-x32/gcc/dwarf2out.c:15035
15035          if ((REG_P (SUBREG_REG (rtl))
(subreg:SI (const:DI (plus:DI (symbol_ref:DI ("a") [flags 0x2] <var_decl
0x7ffff0993e60 a>)
            (const_int 4 [0x4]))) 0)
(gdb) 

gcc.dg/guality/pr45882.c failures may expose other issues.