On 8/31/22 3:51 PM, Segher Boessenkool wrote:
> On Wed, Aug 31, 2022 at 01:53:48PM -0500, Peter Bergner wrote:
>> Question for my own education, when would you use VIEW_CONVERT_EXPR over
>> NOP_EXPR?
>
> VIEW_CONVERT_EXPR is essentially a bit_cast. Only use it when you need
> that, it is sub-optimal if you don't.
Ok. I believe I added a couple of other similar uses of VIEW_CONVERT_EXPR for
pointer casts on the __builtin_vsx_lxvp/stxvp built-ins. I'll try converting
those to use NOP_EXPR too in a separate cleanup patch. Thanks!
>> - tree src_type = TREE_TYPE (src_ptr);
>> + tree src_type = (fncode == RS6000_BIF_DISASSEMBLE_ACC)
>> + ? ptr_vector_quad_type_node :
>> ptr_vector_pair_type_node;
>
> If you split a?b:c over multiple lines, please make it three lines.
Can do, however...
>> ...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???
Peter
