Re: [PATCH] rs6000: Don't ICE when we disassemble an MMA variable [PR101322]

[Peter Bergner <bergner@linux.ibm.com>]

On 8/31/22 6:08 PM, Segher Boessenkool wrote:
> On Wed, Aug 31, 2022 at 05:01:04PM -0500, Peter Bergner wrote:
>> The problem goes away if I use use -O1 or above, I drop -flto or I use
>> the code I originally posted without the ptr_vector_*_type
>>
>> The assert in gimple_canonical_types_compatible_p() we're hitting is:
>> 13673	    default:
>> 13674	      /* Consider all types with language specific trees in them mutually
>> 13675		 compatible.  This is executed only from verify_type and false
>> 13676	         positives can be tolerated.  */
>> 13677	      gcc_assert (!in_lto_p);
>> 13678	      return true;
>>
>> I have no idea why ptr_vector_*_type would behave differently here than
>> build_pointer_type (vector_*_type_node).  Using the build_pointer_type()
>> fixed it for me, so that's why I went with it. :-)  Maybe this is a bug
>> in lto???
> 
> It looks like left-over debugging code.  Or this truly should never
> happen in LTO?

I have no idea.  Either way, I'm going to go with the code that works,
because either it's the "correct" code or it works around buggy code
in lto.  Either is a valid reason to me to use it.

Peter