https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117165
--- Comment #5 from Zdenek Sojka <zsojka at seznam dot cz> --- Similar, with __builtin_ia32_fnstenv(): $ cat testcase.c void foo() { __builtin_ia32_fnstenv(0); } $ x86_64-pc-linux-gnu-gcc -msoft-float testcase.c testcase.c: In function 'foo': testcase.c:1:41: error: unrecognizable insn: 1 | void foo() { __builtin_ia32_fnstenv(0); } | ^ (insn 5 2 0 2 (parallel [ (set (mem:BLK (const_int 0 [0]) [0 A8]) (unspec_volatile:BLK [ (const_int 0 [0]) ] UNSPECV_FNSTENV)) (clobber (reg:XF 8 st)) (clobber (reg:XF 9 st(1))) (clobber (reg:XF 10 st(2))) (clobber (reg:XF 11 st(3))) (clobber (reg:XF 12 st(4))) (clobber (reg:XF 13 st(5))) (clobber (reg:XF 14 st(6))) (clobber (reg:XF 15 st(7))) ]) "testcase.c":1:14 -1 (nil)) during RTL pass: vregs testcase.c:1:41: internal compiler error: in extract_insn, at recog.cc:2869 0x2cc8aae internal_error(char const*, ...) /repo/gcc-trunk/gcc/diagnostic-global-context.cc:518 0xe8690d fancy_abort(char const*, int, char const*) /repo/gcc-trunk/gcc/diagnostic.cc:1697 0x83cc81 _fatal_insn(char const*, rtx_def const*, char const*, int, char const*) /repo/gcc-trunk/gcc/rtl-error.cc:109 0x83ccfe _fatal_insn_not_found(rtx_def const*, char const*, int, char const*) /repo/gcc-trunk/gcc/rtl-error.cc:117 0x82ba82 extract_insn(rtx_insn*) /repo/gcc-trunk/gcc/recog.cc:2869 0x11e913d instantiate_virtual_regs_in_insn /repo/gcc-trunk/gcc/function.cc:1612 0x11e913d instantiate_virtual_regs /repo/gcc-trunk/gcc/function.cc:1995 0x11e913d execute /repo/gcc-trunk/gcc/function.cc:2042 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.