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ICE gcc_jit_block_add_assignment: mismatching types: assignment to input_register #830
Description
snippet:
//@compile-flags: -Zcodegen-backend=gcc
unsafe fn a() {
let j = {};
let pointer = &j;
core::arch::asm !("", in("eax")pointer)
}
fn main() {
unsafe { a() }
}Version information
rustc 1.95.0-nightly (87b272187 2026-01-24)
binary: rustc
commit-hash: 87b272187129343c0efc8f92d253c16958aeac0b
commit-date: 2026-01-24
host: x86_64-unknown-linux-gnu
release: 1.95.0-nightly
LLVM version: 21.1.8
Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zcodegen-backend=gcc
Program output
libgccjit.so: error: : gcc_jit_block_add_assignment: mismatching types: assignment to input_register (type: __int8_t *) from &stack_var_1 (type: __int8_t[0] __attribute__((aligned(1))) *)
error: linking with `cc` failed: exit status: 1
|
= note: "cc" "-m64" "/tmp/icemaker_global_tempdir.SlDjrMXGPvw1/rustc_testrunner_tmpdir_reporting.onHHy0kZiHXB/rustcbLsks4/symbols.o" "<2 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib/{libstd-*,libpanic_unwind-*,libobject-*,libmemchr-*,libaddr2line-*,libgimli-*,libcfg_if-*,librustc_demangle-*,libstd_detect-*,libhashbrown-*,librustc_std_workspace_alloc-*,libminiz_oxide-*,libadler2-*,libunwind-*,liblibc-*,librustc_std_workspace_core-*,liballoc-*,libcore-*,libcompiler_builtins-*}.rlib" "-Wl,-Bdynamic" "-lgcc_s" "-lutil" "-lrt" "-lpthread" "-lm" "-ldl" "-lc" "-L" "/tmp/icemaker_global_tempdir.SlDjrMXGPvw1/rustc_testrunner_tmpdir_reporting.onHHy0kZiHXB/rustcbLsks4/raw-dylibs" "-B<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/bin/gcc-ld" "-fuse-ld=lld" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "<sysroot>/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "outputfile" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs"
= note: some arguments are omitted. use `--verbose` to show all linker arguments
= note: rust-lld: error: cannot open outputfile.mvce.d7c3bcf1ed0de24f-cgu.0.rcgu.o: No such file or directory
collect2: error: ld returned 1 exit status
error: aborting due to 1 previous error
Activity
Dnreikronos commentedon May 30, 2026
This looks already fixed by #874 (commit
6ecabe8), which landed on master on April 30.I reproduced it locally to confirm. If I revert that commit's change and rebuild the backend, the exact error from this report comes back:
With the fix in place the snippet compiles fine. The change casts the input value to the register type before the assignment when the two differ, which covers the
&()case where the pointer is typed as a pointer to a zero-length array.Probably safe to close.
cc// @antoyo and @matthiaskrgr
antoyo commentedon May 31, 2026
Fixed by #874.
Indeed, thanks for pointing that out.