https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80618
--- Comment #4 from seurer at gcc dot gnu.org --- Yup, you were right. Compiling with r247543: seurer@genoa:~/gcc/build/gcc-test$ /home/seurer/gcc/build/gcc-test/gcc/xgcc -B/home/seurer/gcc/build/gcc-test/gcc/ /home/seurer/gcc/gcc-test/gcc/testsuite/gcc.dg/pr50310-2.c -fno-diagnostics-show-caret -fdiagnostics-color=never -O3 -lm -o ./pr50310-2.exe And adding --param vect-max-peeling-for-alignment=0 seurer@genoa:~/gcc/build/gcc-test$ /home/seurer/gcc/build/gcc-test/gcc/xgcc -B/home/seurer/gcc/build/gcc-test/gcc/ /home/seurer/gcc/gcc-test/gcc/testsuite/gcc.dg/pr50310-2.c -fno-diagnostics-show-caret -fdiagnostics-color=never -O3 -lm -o ./pr50310-2.exe --param vect-max-peeling-for-alignment=0 /home/seurer/gcc/gcc-test/gcc/testsuite/gcc.dg/pr50310-2.c: In function 'main': /home/seurer/gcc/gcc-test/gcc/testsuite/gcc.dg/pr50310-2.c:47:1: error: unrecognizable insn: (insn 361 360 176 2 (set (reg:V2DF 342) (not:V2DF (ior:V2DF (reg:V2DF 470) (reg:V2DF 471)))) "/home/seurer/gcc/gcc-test/gcc/testsuite/gcc.dg/pr50310-2.c":30 -1 (nil)) /home/seurer/gcc/gcc-test/gcc/testsuite/gcc.dg/pr50310-2.c:47:1: internal compiler error: in extract_insn, at recog.c:2311 0x108ab353 _fatal_insn(char const*, rtx_def const*, char const*, int, char const*) /home/seurer/gcc/gcc-test/gcc/rtl-error.c:108 0x108ab3b7 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*) /home/seurer/gcc/gcc-test/gcc/rtl-error.c:116 0x108701d7 extract_insn(rtx_insn*) /home/seurer/gcc/gcc-test/gcc/recog.c:2311 0x1120fe63 decompose_multiword_subregs /home/seurer/gcc/gcc-test/gcc/lower-subreg.c:1467 0x1121150b execute /home/seurer/gcc/gcc-test/gcc/lower-subreg.c:1734 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.