On 12-10-29 12:21 PM, Richard Sandiford wrote:
Vladimir Makarov <vmaka...@redhat.com> writes:
H.J. in
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55116
reported an interesting address
(and:DI (subreg:DI (plus:SI (ashift:SI (reg:SI 96 [ glob_vol_int.22 ])
(const_int 2 [0x2]))
(symbol_ref:SI ("glob_vol_int_arr") <var_decl
0x7ffff03c2720 glob_vol_int_arr>)) 0)
(const_int 4294967295 [0xffffffff]))
which can not be correctly extracted. Here `and' with `subreg'
behaves as an address mutation.
The following patch fixes the problem.
Ok to commit, Richard?
Heh, I wondered if subregs might still be used like that, and was almost
tempted to add them just in case.
I think this particular case is really a failed canonicalisation and that:
(and:DI (subreg:DI (foo:SI ...) 0) (const_int 0xffffffff))
ought to be:
(zero_extend:DI (foo:SI ...))
Yes, that was my thought too.
But I know I've approved MIPS patches to accept
(and:DI ... (const_int 0xffffffff)) as an alternative.
Index: rtlanal.c
===================================================================
--- rtlanal.c (revision 192942)
+++ rtlanal.c (working copy)
@@ -5459,6 +5459,11 @@ strip_address_mutations (rtx *loc, enum
else if (code == AND && CONST_INT_P (XEXP (*loc, 1)))
/* (and ... (const_int -X)) is used to align to X bytes. */
loc = &XEXP (*loc, 0);
+ else if (code == SUBREG
+ && ! REG_P (XEXP (*loc, 0)) && ! MEM_P (XEXP (*loc, 0)))
+ /* (subreg (operator ...) ...) usually inside and is used for
+ mode conversion too. */
+ loc = &XEXP (*loc, 0);
I think the condition should be:
else if (code == SUBREG
&& !OBJECT_P (SUBREG_REG (*loc))
&& subreg_lowpart (*loc))
OK with that change, if it works.
Yes, it works.
I've submitted the following patch.
Index: rtlanal.c
===================================================================
--- rtlanal.c (revision 192942)
+++ rtlanal.c (working copy)
@@ -5459,6 +5459,12 @@ strip_address_mutations (rtx *loc, enum
else if (code == AND && CONST_INT_P (XEXP (*loc, 1)))
/* (and ... (const_int -X)) is used to align to X bytes. */
loc = &XEXP (*loc, 0);
+ else if (code == SUBREG
+ && !OBJECT_P (SUBREG_REG (*loc))
+ && subreg_lowpart_p (*loc))
+ /* (subreg (operator ...) ...) inside and is used for mode
+ conversion too. */
+ loc = &XEXP (*loc, 0);
else
return loc;
if (outer_code)
