Re: [patch] fix regrename pass to ensure renamings produce valid insns

[Chung-Lin Tang <cltang@codesourcery.com>]

On 2015/6/30 下午 01:13, Chung-Lin Tang wrote:
> On 2015/6/30 12:22 PM, Sandra Loosemore wrote:
>> On 06/29/2015 09:07 PM, Kito Cheng wrote:
>>> Hi all:
>>>
>>> This patch seem will broken when disable assert checking for c6x....
>>>
>>> Index: gcc/config/c6x/c6x.c
>>> ===================================================================
>>> --- gcc/config/c6x/c6x.c (revision 225104)
>>> +++ gcc/config/c6x/c6x.c (working copy)
>>> @@ -3516,7 +3516,7 @@ try_rename_operands (rtx_insn *head, rtx
>>>     best_reg =
>>>       find_rename_reg (this_head, super_class, &unavailable, old_reg, true);
>>>
>>> -  regrename_do_replace (this_head, best_reg);
>>> +  gcc_assert (regrename_do_replace (this_head, best_reg));
>>>
>>>     count_unit_reqs (new_reqs, head, PREV_INSN (tail));
>>>     merge_unit_reqs (new_reqs);
>>> @@ -3529,7 +3529,7 @@ try_rename_operands (rtx_insn *head, rtx
>>>          unit_req_imbalance (reqs), unit_req_imbalance (new_reqs));
>>>       }
>>>     if (unit_req_imbalance (new_reqs) > unit_req_imbalance (reqs))
>>> -    regrename_do_replace (this_head, old_reg);
>>> +    gcc_assert (regrename_do_replace (this_head, old_reg));
>>>     else
>>>       memcpy (reqs, new_reqs, sizeof (unit_req_table));
>>>
>>
>> I'm sorry; do you have a suggestion for a fix?  I thought this was the change I was asked to make, and as I noted previously, I'm not set up to test (or even build) for this target.
>>
>> -Sandra the obviously confused :-(
> 
> You probably have to separate out the regrename_do_replace() bool result into a variable,
> placing the whole call into the gcc_assert() might make it disappear when assertions are turned off.

I notice the way gcc_assert() is defined in system.h now, the test won't disappear even when runtime checks
are disabled, though you might still adjust it to avoid any programmer confusion.

Chung-Lin