https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121193
Bug ID: 121193
Summary: ICE: in get_alias_set, at alias.cc:955 with may_alias
on volatile
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: iamanonymous.cs at gmail dot com
Target Milestone: ---
When compiling this program, GCC-16 crashes:
```
volatile __attribute__((may_alias)) float a[1];
```
The GCC version:
```
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/home/software/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/16.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++ --prefix=/home/software/gcc-trunk --enable-coverage
--disable-werror --enable-checking=yes
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 16.0.0 20250613 (experimental) (GCC)
```
The full stack dump:
```
mutant.c:1:1: internal compiler error: in get_alias_set, at alias.cc:955
1 | volatile __attribute__((may_alias)) float a[1];
| ^~~~~~~~
0x5554b38 internal_error(char const*, ...)
../../gcc/gcc/diagnostic-global-context.cc:517
0x54d2d0a fancy_abort(char const*, int, char const*)
../../gcc/gcc/diagnostic.cc:1803
0x1281d58 get_alias_set(tree_node*)
../../gcc/gcc/alias.cc:955
0x15c6a17 set_mem_attributes_minus_bitpos(rtx_def*, tree_node*, int,
poly_int<1u, long>)
../../gcc/gcc/emit-rtl.cc:1989
0x15c8132 set_mem_attributes(rtx_def*, tree_node*, int)
../../gcc/gcc/emit-rtl.cc:2194
0x2a52303 make_decl_rtl(tree_node*)
../../gcc/gcc/varasm.cc:1645
0x2a57734 assemble_variable(tree_node*, int, int, int)
../../gcc/gcc/varasm.cc:2528
0x2a8e1fc varpool_node::assemble_decl()
../../gcc/gcc/varpool.cc:596
0x1433181 cgraph_order_sort::process()
../../gcc/gcc/cgraphunit.cc:2144
0x143372d output_in_order
../../gcc/gcc/cgraphunit.cc:2209
0x14343cf symbol_table::compile()
../../gcc/gcc/cgraphunit.cc:2415
0x1434de1 symbol_table::finalize_compilation_unit()
../../gcc/gcc/cgraphunit.cc:2607
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.
```
But on trunk version, it gets internal compiler error: 'verify_type' failed.
Complier Explorer on trunk: https://gcc.godbolt.org/z/G7PTYGoob
