https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65671
Bug ID: 65671 Summary: Assembly failure (invalid register operand) with -O3 -mavx512vl Product: gcc Version: 5.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: jamrial at gmail dot com https://raw.githubusercontent.com/foo86/dcadec/e884d9a0d9127528bdc47c1f8db392363fb50876/libdcadec/idct_float.c gcc -O3 -mavx512f -mavx512vl -c -o libdcadec/idct_float.o libdcadec/idct_float.c /tmp/cc3BQBvH.s: Assembler messages: /tmp/cc3BQBvH.s:1602: Error: invalid register operand for `vextractf128' /tmp/cc3BQBvH.s:1624: Error: invalid register operand for `vextractf128' /tmp/cc3BQBvH.s:1670: Error: invalid register operand for `vextractf128' Lines in question from the resulting assembly file 1602: vextractf128 $0x1, %ymm20, 144(%rdx) 1624: vextractf128 $0x1, %ymm24, 272(%rdx) 1670: vextractf128 $0x1, %ymm19, 400(%rdx) GCC 5.0.0 (20150329 snapshot) on x86_64-unknown-linux-gnu. Works fine with -mavx512f alone, so sounds like the assembler is trying to use VEX coding scheme with the new registers instead of EVEX.