Fix crash in vect_is_slp_reduction

[Ryan Mansfield]

On 11-05-20 10:17 AM, Richard Guenther wrote:
> On Fri, May 20, 2011 at 4:06 PM, Ryan Mansfield<rmansfield@qnx.com>  wrote:
>> There is a crash in vect_is_slp_reduction where use_stmt doesn't get
>> initialized in the FOR_EACH_IMM_USE_FAST loop.
>>
>> 1718          FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
>> (gdb) call debug_tree(lhs)
>>   <ssa_name 0x7ffff6e3a5a0
>>     type<integer_type 0x7ffff7f8c7e0 int32_t sizes-gimplified public SI
>>         size<integer_cst 0x7ffff7ec47e0 constant 32>
>>         unit size<integer_cst 0x7ffff7ec4580 constant 4>
>>         align 32 symtab 0 alias set -1 canonical type 0x7ffff7ecb498
>> precision 32 min<integer_cst 0x7ffff7ec4780 -2147483648>  max<integer_cst
>> 0x7ffff7ec47a0 2147483647>  context<translation_unit_decl 0x7ffff7f98508
>> D.1314>
>>         pointer_to_this<pointer_type 0x7ffff7f9f930>>
>>     var<var_decl 0x7ffff6e1ce60 g_29_lsm.18>def_stmt g_29_lsm.18_137 = PHI
>> <g_29_lsm.18_87(15), D.2113_96(18)>
>>
>>     version 137>
>> (gdb) n
>> 1742          if (found)
>> (gdb)
>> 1746          if (gimple_code (use_stmt) == GIMPLE_PHI)
>> (gdb)
>>
>> Program received signal SIGSEGV, Segmentation fault.
>> 0x0000000000980f22 in gimple_code (g=0x0) at ../../gcc/gimple.h:1098
>> 1098      return g->gsbase.code;
>>
>> Is the following sufficient?
>
> No, we shouldn't arrive with a NULL use_stmt here.

OK, thanks. I've filed PR49087 with a testcase.

Regards,

Ryan Mansfield