[Bug middle-end/55259] New: plus_constant doesn't handle zero-extended address properly

[Bug middle-end/55259] New: plus_constant doesn't handle zero-extended address properly

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55259

             Bug #: 55259
           Summary: plus_constant doesn't handle zero-extended address
                    properly
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: hjl.tools@gmail.com


For address,

#0  plus_constant (mode=SImode, x=0x7ffff0fadf40, c=8)
    at /export/gnu/import/git/gcc/gcc/explow.c:211
#1  0x00000000006f9b04 in adjust_address_1 (memref=0x7ffff0fff2e8, 
    mode=DImode, offset=8, validate=1, adjust_address=1, adjust_object=0)
    at /export/gnu/import/git/gcc/gcc/emit-rtl.c:2113
#2  0x0000000000cdd259 in split_double_mode (mode=TImode, 
    operands=0x7fffffffd828, num=0, lo_half=0x7fffffffd8f0, 
    hi_half=0x7fffffffd8f8)
    at /export/gnu/import/git/gcc/gcc/config/i386/i386.c:14721
#3  0x0000000000ceafe7 in ix86_split_to_parts (operand=0x7ffff0fff2e8, 
    parts=0x7fffffffd8f0, mode=TImode)
    at /export/gnu/import/git/gcc/gcc/config/i386/i386.c:20695
#4  0x0000000000ceb4ad in ix86_split_long_move (
    operands=0x17a5fa0 <recog_data>)
    at /export/gnu/import/git/gcc/gcc/config/i386/i386.c:20794

Breakpoint 2, plus_constant (mode=DImode, x=0x7ffff0fadf30, c=8)
    at /export/gnu/import/git/gcc/gcc/explow.c:96
96          zero_extend_mode = GET_MODE (x);
(gdb) call debug_rtx (x)
(zero_extend:DI (reg:SI 0 ax [82]))
(gdb) 

it should generate

(gdb) call debug_rtx (x)
(zero_extend:DI (plus:SI (reg:SI 0 ax [82])
        (const_int 8 [0x8])))
(gdb)

Instead, plus_constant generates

(gdb) call debug_rtx (addr)
(plus:DI (zero_extend:DI (reg:SI 0 ax [82]))
    (const_int 8 [0x8]))

[Bug middle-end/55259] plus_constant doesn't handle zero-extended address properly

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55259

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> 2012-11-10 04:13:32 UTC ---
A potential fix:

diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index 95bbfa7..d7c454c 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -2109,6 +2109,12 @@ adjust_address_1 (rtx memref, enum machine_mode mode,
HOS
T_WIDE_INT offset,
     addr = gen_rtx_LO_SUM (address_mode, XEXP (addr, 0),
                    plus_constant (address_mode,
                           XEXP (addr, 1), offset));
+      else if (GET_CODE (addr) == ZERO_EXTEND)
+    {
+      addr = XEXP (addr, 0);
+      addr = plus_constant (GET_MODE (addr), addr, offset);
+      addr = gen_rtx_ZERO_EXTEND (address_mode, addr);
+    }
       else
     addr = plus_constant (address_mode, addr, offset);
     }

[Bug middle-end/55259] plus_constant doesn't handle zero-extended address properly

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55259

--- Comment #2 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2012-11-11 21:52:53 UTC ---
Author: ebotcazou
Date: Sun Nov 11 21:52:49 2012
New Revision: 193415

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193415
Log:
    PR rtl-optimization/55247
    PR middle-end/55259
    * emit-rtl.c (adjust_address_1): If POINTERS_EXTEND_UNSIGNED > 0,
    handle ZERO_EXTEND.
    * recog.c (offsettable_address_addr_space_p): Likewise.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr55247-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/emit-rtl.c
    trunk/gcc/recog.c
    trunk/gcc/testsuite/ChangeLog

[Bug middle-end/55259] plus_constant doesn't handle zero-extended address properly

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55259

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.8.0

--- Comment #3 from H.J. Lu <hjl.tools at gmail dot com> 2012-11-11 23:54:51 UTC ---
Fixed.