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

["Kewen.Lin" <linkw@linux.ibm.com>]

>>> ...and of course, now I can't recreate that issue at all and the
>>> ptr_vector_*_type use work fine now.  Strange! ...so ok, changed.
>>> Maybe the behavior changed since my PR106017 fix went in???
>>
>> That is my best guess as well.  But, how did that help this test?
> 
> It didn't. :-)   During my bootstrap, I hit the gimple verification issue
> I mentioned seeing earlier.  My problem was I thought I hit it with the
> test case, but it was exposed on a different test case in the testsuite.
> Here's what I'm seeing, which only happens when using -O0 -flto:
> 
> rain6p1% gcc -O0 -mcpu=power10 -flto pr102347.c 
> lto1: internal compiler error: in gimple_canonical_types_compatible_p, at tree.cc:13677
> 0x11930a97 gimple_canonical_types_compatible_p(tree_node const*, tree_node const*, bool)
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/tree.cc:13677
> 0x1192f1ab verify_type_variant
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/tree.cc:13377
> 0x11930beb verify_type(tree_node const*)
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/tree.cc:13700
> 0x106bbd37 lto_fixup_state
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/lto/lto-common.cc:2629
> 0x106bbff3 lto_fixup_decls
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/lto/lto-common.cc:2660
> 0x106bce13 read_cgraph_and_symbols(unsigned int, char const**)
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/lto/lto-common.cc:2901
> 0x1067bcbf lto_main()
> 	/home/bergner/gcc/gcc-fsf-mainline-pr101322/gcc/lto/lto.cc:656
> Please submit a full bug report, with preprocessed source (by using -freport-bug).
> Please include the complete backtrace with any bug report.
> See <https://gcc.gnu.org/bugs/> for instructions.
> lto-wrapper: fatal error: /home/bergner/gcc/build/gcc-fsf-mainline-pr101322-debug/gcc/xgcc returned 1 exit status
> compilation terminated.
> /home/bergner/binutils/install/binutils-power10/bin/ld: error: lto-wrapper failed
> collect2: error: ld returned 1 exit status
> 
> 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???

Thanks for your time to reproduce this!

The only difference is that ptr_vector_*_type are built from the
qualified_type based on vector_*_type_node, instead of directly from
vector_*_type_node.  I'm interested to have a further look at this later.

BR,
Kewen