[PATCH][i386]Fix PR 57756

[Richard Biener]

On Sat, Sep 21, 2013 at 4:09 AM, Sriraman Tallam <tmsriram@google.com> wrote:
> Forgot to add the test case. Patch updated.
>
> Sri
>
> On Fri, Sep 20, 2013 at 7:06 PM, Sriraman Tallam <tmsriram@google.com> wrote:
>> On Wed, Aug 14, 2013 at 3:38 AM, Richard Biener
>> <richard.guenther@gmail.com> wrote:
>>> On Wed, Aug 14, 2013 at 2:02 AM, Sriraman Tallam <tmsriram@google.com>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>>     I have attached a patch to fix PR57756.  Description:  The
>>>> following program,
>>>>
>>>> __attribute__((always_inline,target("sse4.2")))
>>>> __inline int callee ()
>>>> {
>>>>   return 0;
>>>> }
>>>>
>>>> __attribute__((target("sse")))
>>>> __inline int caller ()
>>>> {
>>>>   return callee();
>>>> }
>>>>
>>>> does not generate an error and callee is inlined into caller. This is
>>>> because callee has a higher target ISA.  Interchanging the position of
>>>> caller and callee will generate the correct error. Also, removing the
>>>> target attribute from caller will generate the error.
>>>>
>>>> The reason for the bug is that when the caller's target options are
>>>> processed, global_options contain the ISA flags of the callee
>>>> (previously processed) and doing this in i386-common.c, where opts is
>>>> global_options:
>>>>
>>>> opts->x_ix86_isa_flags |= OPTION_MASK_ISA_SSE_SET;
>>>>
>>>> is not changing global options.  The fix is to reset global_options to
>>>> the default each time a new target option needs to be processed.
>>>
>>>
>>> Shouldn't  ix86_valid_target_attribute_tree be refactored to work on a
>>> selected
>>> opt structure rather than global_options?
>>
>> I have attached a patch that does the refactoring of
>> ix86_valid_target_attribute_tree. In that process I had to refactor
>> ix86_valid_target_attribute_inner_p and ix86_option_override_internal.
>> This made it a large patch because global_options structure is touched
>> by these functions in multiple places and through vvarious aliases
>> like ix86_arch_string for instance. In effect, this frees these
>> functions from depending on global_options and the code in
>> ix86_alid_target_attribute_p shows how the original bug can be fixed
>> by just using a different gcc_options structure.

This looks nice.  I suppose you grepped for effected targets and rs6000
was the only one besides i386.

This is ok given target maintainers do not object within 24h and the test
successfully bootstrapped and passed regression tests.

Thanks,
Richard.

>> Please review.
>>
>> Thanks
>> Sri
>>
>>
>>
>>> Richard.
>>>
>>>>
>>>> Patch ok?
>>>>
>>>> Thanks
>>>> Sri
>>>
>>>