http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47744
--- Comment #17 from H.J. Lu <hjl.tools at gmail dot com> 2011-07-17 21:21:01
UTC ---
(In reply to comment #16)
> Following patch to original ix86_decompose_address solves all failures for me:
>
> --cut here--
> Index: i386.c
> ===================================================================
> --- i386.c (revision 176373)
> +++ i386.c (working copy)
> @@ -11149,8 +11149,11 @@ ix86_decompose_address (rtx addr, struct
> return 0;
> break;
>
> - case REG:
> case SUBREG:
> + if (GET_CODE (op) != REG)
> + return 0;
> +
> + case REG:
> if (!base)
> base = op;
> else if (!index)
> --cut here--
>
> The patch simply prevents subregs of anything else than registers in
> addresses.
>
> So, instead of mess as in comment 14, we have a sequence of two instructions:
>
> (insn 185 87 89 3 (set (reg:DI 0 ax)
> (plus:DI (reg/f:DI 7 sp)
> (const_int 200 [0xc8]))) pr47744.c:5 248 {*lea_1}
> (nil))
>
> (insn 89 185 90 3 (set (reg:SI 40 r11 [177])
> (plus:SI (plus:SI (mult:SI (reg:SI 40 r11 [175])
> (const_int 8 [0x8]))
> (reg:SI 0 ax))
> (const_int -160 [0xffffffffffffff60]))) pr47744.c:5 286
> {*lea_general_3}
> (nil))
>
> Please note, that "normal" lea instructions are now generated, no need for
> some
> special x32 versions.
>
> BTW: I'd also argue that this sequence is more correct w.r.t. to overflows,
> but
> I didn't investigate this since it is already late in the night here...
I will give it a try on x32 branch. Thanks.
