* [RS6000] Fix PR54131, ICE building 416.gamess
[not found] <OF1B2923F2.E3980D6E-ON86257A4B.00769310-86257A4B.00769C1F@us.ibm.com>
@ 2012-07-31 11:59 ` Alan Modra
2012-07-31 14:36 ` David Edelsohn
0 siblings, 1 reply; 2+ messages in thread
From: Alan Modra @ 2012-07-31 11:59 UTC (permalink / raw)
To: David Edelsohn, Pat Haugen; +Cc: gcc-patches
This cures the 'Y' constraint of being overly restrictive with lo_sum
offsets. I've added a comment that explains why it is wrong to limit
the range of lo_sum offsets. Bootstrapped and regressiotn tested
powerpc-linux. OK to apply?
PR target/54131
* config/rs6000/rs6000.c (mem_operand_gpr): Don't limit range
of lo_sum offsets. Comment. Assert mode at least word size
rather than bypassing powerpc64 word offset check.
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 189996)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -5008,24 +5008,38 @@
Offsetting a lo_sum should not be allowed, except where we know by
alignment that a 32k boundary is not crossed, but see the ???
- comment in rs6000_legitimize_reload_address. */
+ comment in rs6000_legitimize_reload_address. Note that by
+ "offsetting" here we mean a further offset to access parts of the
+ MEM. It's fine to have a lo_sum where the inner address is offset
+ from a sym, since the same sym+offset will appear in the high part
+ of the address calculation. */
bool
mem_operand_gpr (rtx op, enum machine_mode mode)
{
unsigned HOST_WIDE_INT offset;
int extra;
+ rtx addr = XEXP (op, 0);
- op = address_offset (XEXP (op, 0));
+ op = address_offset (addr);
if (op == NULL_RTX)
return true;
offset = INTVAL (op);
+ if (TARGET_POWERPC64 && (offset & 3) != 0)
+ return false;
+
+ if (GET_CODE (addr) == LO_SUM)
+ /* We know by alignment that ABI_AIX medium/large model toc refs
+ will not cross a 32k boundary, since all entries in the
+ constant pool are naturally aligned and we check alignment for
+ other medium model toc-relative addresses. For ABI_V4 and
+ ABI_DARWIN lo_sum addresses, we just check that 64-bit
+ offsets are 4-byte aligned. */
+ return true;
+
extra = GET_MODE_SIZE (mode) - UNITS_PER_WORD;
- if (extra < 0)
- extra = 0;
- else if (TARGET_POWERPC64 && (offset & 3) != 0)
- return false;
+ gcc_assert (extra >= 0);
return offset + 0x8000 < 0x10000u - extra;
}
\f
--
Alan Modra
Australia Development Lab, IBM
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [RS6000] Fix PR54131, ICE building 416.gamess
2012-07-31 11:59 ` [RS6000] Fix PR54131, ICE building 416.gamess Alan Modra
@ 2012-07-31 14:36 ` David Edelsohn
0 siblings, 0 replies; 2+ messages in thread
From: David Edelsohn @ 2012-07-31 14:36 UTC (permalink / raw)
To: Alan Modra, Pat Haugen, gcc-patches
On Tue, Jul 31, 2012 at 7:51 AM, Alan Modra <amodra@gmail.com> wrote:
> This cures the 'Y' constraint of being overly restrictive with lo_sum
> offsets. I've added a comment that explains why it is wrong to limit
> the range of lo_sum offsets. Bootstrapped and regressiotn tested
> powerpc-linux. OK to apply?
>
> PR target/54131
> * config/rs6000/rs6000.c (mem_operand_gpr): Don't limit range
> of lo_sum offsets. Comment. Assert mode at least word size
> rather than bypassing powerpc64 word offset check.
Okay.
Thanks, David
^ permalink raw reply [flat|nested] 2+ messages in thread
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2012-07-31 11:59 ` [RS6000] Fix PR54131, ICE building 416.gamess Alan Modra
2012-07-31 14:36 ` David Edelsohn
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