On Wed, Nov 18, 2015 at 09:52:41AM +1030, Alan Modra wrote:
> David noticed that gcc112 was generating gcc/auto-host.h with
> #define POWERPC64_TOC_POINTER_ALIGNMENT 32768
>
> This is not the correct value of either 8 or 256 depending on how old
> ld is. On investigating I found the cause is Fedora 21 modifying the
> toolchain to default to -z relro. ld -z relro puts the relro gap just
> before .got (prior to my patches reordering sections for relro on
> powerpc64). That unfortunately aligns .got, defeating the deliberate
> mis-alignment of .got in the testcase.
>
> Fixed with the following obvious patch and committed to mainline.
>
> Incidentally, bootstrap fails for me on powerpc64 due to "comparison
> is always true due to limited range of data type [-Wtype-limits]"
> && GET_MODE_SIZE (mode) <= POWERPC64_TOC_POINTER_ALIGNMENT));
> since my POWERPC64_TOC_POINTER_ALIGNMENT is 256 and mode_size is an
> unsigned char array. Grrr, so what code obfuscation do we use here to
> work around this annoying warning?
For the moment, I added the following to my local build. However, I can't
build libgcc on an x86 cross compiler:
In file included from
/home/meissner/fsf-src/ieee/libgcc/soft-fp/soft-fp.h:321:0,
from addkf3.c:33:
addkf3.c: In function ‘__addkf3’:
/home/meissner/fsf-src/ieee/libgcc/soft-fp/op-common.h:2057:6: internal
compiler error: in convert_move, at expr.c:286
(r) = __builtin_clzl (x); \
~~~~^~~~~~~~~~~~~~~~~~~~
/home/meissner/fsf-src/ieee/libgcc/soft-fp/op-2.h:129:2: note: in expansion of
macro ‘__FP_CLZ’
__FP_CLZ ((R), X##_f1); \
^~~~~~~~
/home/meissner/fsf-src/ieee/libgcc/soft-fp/op-common.h:827:8: note: in
expansion of macro ‘_FP_FRAC_CLZ_2’
_FP_FRAC_CLZ_##wc (_FP_ADD_INTERNAL_diff, R); \
^~~~~~~~~~~~~
/home/meissner/fsf-src/ieee/libgcc/soft-fp/op-common.h:850:34: note: in
expansion of macro ‘_FP_ADD_INTERNAL’
#define _FP_ADD(fs, wc, R, X, Y) _FP_ADD_INTERNAL (fs, wc, R, X, Y, '+')
^~~~~~~~~~~~~~~~
/home/meissner/fsf-src/ieee/libgcc/soft-fp/quad.h:306:29: note: in expansion of
macro ‘_FP_ADD’
# define FP_ADD_Q(R, X, Y) _FP_ADD (Q, 2, R, X, Y)
^~~~~~~
addkf3.c:48:3: note: in expansion of macro ‘FP_ADD_Q’
FP_ADD_Q (R, A, B);
^~~~~~~~
0x78432e convert_move(rtx_def*, rtx_def*, int)
/home/meissner/fsf-src/ieee/gcc/expr.c:286
0x8753a6 expand_direct_optab_fn
/home/meissner/fsf-src/ieee/gcc/internal-fn.c:2132
0x6686ca expand_call_stmt
/home/meissner/fsf-src/ieee/gcc/cfgexpand.c:2565
0x6698e4 expand_gimple_stmt_1
/home/meissner/fsf-src/ieee/gcc/cfgexpand.c:3525
0x6698e4 expand_gimple_stmt
/home/meissner/fsf-src/ieee/gcc/cfgexpand.c:3688
0x66b2fe expand_gimple_basic_block
/home/meissner/fsf-src/ieee/gcc/cfgexpand.c:5694
0x66f226 execute
/home/meissner/fsf-src/ieee/gcc/cfgexpand.c:6309
Please submit a full bug report,
Here is the temporary patch I'm using to get past rs6000.c. But I suspect the
TOC alignment should never be 256.
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 230511)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -7992,14 +7992,21 @@ rs6000_cannot_force_const_mem (machine_m
can be addressed relative to the toc pointer. */
static bool
-use_toc_relative_ref (rtx sym, machine_mode mode)
+use_toc_relative_ref (rtx sym, machine_mode mode ATTRIBUTE_UNUSED)
{
return ((constant_pool_expr_p (sym)
&& ASM_OUTPUT_SPECIAL_POOL_ENTRY_P (get_pool_constant (sym),
get_pool_mode (sym)))
|| (TARGET_CMODEL == CMODEL_MEDIUM
&& SYMBOL_REF_LOCAL_P (sym)
- && GET_MODE_SIZE (mode) <= POWERPC64_TOC_POINTER_ALIGNMENT));
+ /* If the linker says that TOC alignment is 256 bits, this test
+ will always be true, since GET_MODE_SIZE returns an unsigned
+ char on the PowerPC. Prevent an warning/error in this
+ case. */
+#if POWERPC64_TOC_POINTER_ALIGNMENT < 256
+ && GET_MODE_SIZE (mode) <= POWERPC64_TOC_POINTER_ALIGNMENT
+#endif
+ ));
}
/* Our implementation of LEGITIMIZE_RELOAD_ADDRESS. Returns a value to
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.vnet.ibm.com, phone: +1 (978) 899-4797
