https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80382
--- Comment #9 from Peter Bergner <bergner at gcc dot gnu.org> --- It seems you can call creduce multiple times and see some reduction. Here's a reduced test case: bergner@pike:~/gcc/BUGS/PR80382$ cat bug.ii namespace a { typedef enum {} b; template <typename c> struct g { c d; g(c) {} b f; void i() { c a; __atomic_load(&d, &a, f); } }; } namespace ad { using a::g; } using ad::g; class k { int *ak; int h; }; class l { public: template <typename j> l(j); }; class m { public: m() : as(k()), au(1) { as.i(); } g<k> as; l au; }; enum av : int; class n { public: n(int, av); }; class G { G(); bool ay; m e; n bf; }; enum av : int { bg }; int bh(); G::G() : bf(bh(), bg) {} bergner@pike:~/gcc/BUGS/PR80382$ /home/bergner/gcc/build/gcc-fsf-mainline-pr80382-debug/gcc/xg++ -B/home/bergner/gcc/build/gcc-fsf-mainline-pr80382-debug/gcc -O3 -std=c++11 -mtune=power8 -mcpu=power8 -mno-lra -S bug.ii bug.ii: In constructor ‘G::G()’: bug.ii:44:24: error: unrecognizable insn: G::G() : bf(bh(), bg) {} ^ (insn 12 11 13 2 (set (reg:PTI 165) (unspec:PTI [ (mem/v:TI (plus:DI (reg/f:DI 161 [ this ]) (const_int 8 [0x8])) [-1 S16 A128]) ] UNSPEC_LSQ)) "bug.ii":9 -1 (nil)) bug.ii:44:24: internal compiler error: in extract_insn, at recog.c:2311 0x110c3cf7 _fatal_insn(char const*, rtx_def const*, char const*, int, char const*) /home/bergner/gcc/gcc-fsf-mainline-pr80382/gcc/rtl-error.c:108 0x110c3d6b _fatal_insn_not_found(rtx_def const*, char const*, int, char const*) /home/bergner/gcc/gcc-fsf-mainline-pr80382/gcc/rtl-error.c:116 0x1104ac5b extract_insn(rtx_insn*) /home/bergner/gcc/gcc-fsf-mainline-pr80382/gcc/recog.c:2311 0x10c0063f instantiate_virtual_regs_in_insn /home/bergner/gcc/gcc-fsf-mainline-pr80382/gcc/function.c:1589 0x10c0260f instantiate_virtual_regs /home/bergner/gcc/gcc-fsf-mainline-pr80382/gcc/function.c:1957 0x10c027af execute /home/bergner/gcc/gcc-fsf-mainline-pr80382/gcc/function.c:2006 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions.