"Yangfei (Felix)" <felix.y...@huawei.com> writes:
> Turns out that this ICE triggers under x86 -m32.
>
> Command to reproduce:
> ~/build-gcc/x86_64-pc-linux-gnu/32/libgcc$ gcc -g -O2 -m32 -O2 -g -O2
> -DIN_GCC -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual
> -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition -isystem
> ./include -fpic -mlong-double-80 -DUSE_ELF_SYMVER -fcf-protection -mshstk
> -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector -fpic
> -mlong-double-80 -DUSE_ELF_SYMVER -fcf-protection -mshstk -I. -I.
> -I../../.././gcc -I../../../../gcc-git/libgcc -I../../../../gcc-git/libgcc/.
> -I../../../../gcc-git/libgcc/../gcc -I../../../../gcc-git/libgcc/../include
> -I../../../../gcc-git/libgcc/config/libbid -DENABLE_DECIMAL_BID_FORMAT
> -DHAVE_CC_TLS -DUSE_TLS -o _isinfd32.o -MT _isinfd32.o -MD -MP -MF
> _isinfd32.dep -c ../../../../gcc-git/libgcc/config/libbid/_isinfd32.c
>
> Source:
> 28 int
> 29 isinfd32 (_Decimal32 x) {
> 30 int res;
> 31 UINT64 x64;
> 32 union decimal32 ux;
> 33
> 34 ux.d = x;
> 35 x64 = __bid32_to_bid64 (ux.i);
> 36 res = __bid64_isInf (x64);
> 37 return (res);
> 38 }
>
> On the crash site (emit_single_push_insn), we have three insns:
> (gdb) p debug_rtx (prev)
> (insn 12 0 13 (parallel [
> (set (reg/f:SI 7 sp)
> (plus:SI (reg/f:SI 7 sp)
> (const_int -12 [0xfffffffffffffff4])))
> (clobber (reg:CC 17 flags))
> ]) "../../../../gcc-git/libgcc/config/libbid/_isinfd32.c":35:9 -1
> (expr_list:REG_ARGS_SIZE (const_int 12 [0xc])
> (nil)))
> $1 = void
> (gdb) p debug_rtx (last)
> (insn 14 13 0 (set (mem:SI (reg/f:SI 87) [0 S4 A32])
> (subreg:SI (reg/v:SD 86 [ x ]) 0))
> "../../../../gcc-git/libgcc/config/libbid/_isinfd32.c":35:9 -1
> (nil))
> $2 = void
> (gdb) p debug_rtx (PREV_INSN (last))
> (insn 13 12 14 (set (reg/f:SI 87)
> (pre_dec:SI (reg/f:SI 7 sp)))
> "../../../../gcc-git/libgcc/config/libbid/_isinfd32.c":35:9 -1
> (nil))
> $3 = void
>
> Here, insn 13 is invalid. It is emitted by: x = adjust_address (x, GET_MODE
> (y_inner), 0);
>
> The v5 patch attached addressed this issue.
>
> There two added changes compared with the v4 patch:
> 1. In candidate_mem_p, mov_optab for innermode should be available.
> In this case, mov_optab for SDmode is not there and subreg are added
> back by emit_move_insn_1. So we won't get the benefit with the patch.
I agree we should have this check. I think the rule applies to all
of the transforms though, not just the mem one, so we should add
the check to the register and constant cases too.
> 2. Instead of using adjust_address, I changed to use adjust_address_nv to
> avoid the emit of invalid insn 13.
> The latter call to validize_mem() in emit_move_insn will take care of the
> address for us.
The validation performed by validize_mem is the same as that performed
by adjust_address, so the only case this should make a difference is
for push_operands:
/* If X or Y are memory references, verify that their addresses are valid
for the machine. */
if (MEM_P (x)
&& (! memory_address_addr_space_p (GET_MODE (x), XEXP (x, 0),
MEM_ADDR_SPACE (x))
&& ! push_operand (x, GET_MODE (x))))
x = validize_mem (x);
if (MEM_P (y)
&& ! memory_address_addr_space_p (GET_MODE (y), XEXP (y, 0),
MEM_ADDR_SPACE (y)))
y = validize_mem (y);
So I think the fix is to punt on push_operands instead (and continue
to use adjust_address rather than adjust_address_nv).
Thanks,
Richard
