https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65167
--- Comment #4 from Ilya Enkovich <enkovich.gnu at gmail dot com> --- ix86_function_arg_regno_p doesn't recognize bnd registers as args. Also avoid_func_arg_motion doesn't work for BNDSTX because it is not a single set. This patch works for reproducer: diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 71a5b22..acbe25f 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -6068,6 +6068,9 @@ ix86_function_arg_regno_p (int regno) int i; const int *parm_regs; + if (TARGET_MPX && BND_REGNO_P (regno)) + return true; + if (!TARGET_64BIT) { if (TARGET_MACHO) @@ -26846,6 +26849,16 @@ avoid_func_arg_motion (rtx_insn *first_arg, rtx_insn *insn) rtx set; rtx tmp; + /* Add anti dependencies for bounds stores. */ + if (INSN_P (insn) + && GET_CODE (PATTERN (insn)) == PARALLEL + && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == UNSPEC + && XINT (XVECEXP (PATTERN (insn), 0, 0), 1) == UNSPEC_BNDSTX) + { + add_dependence (first_arg, insn, REG_DEP_ANTI); + return; + } + set = single_set (insn); if (!set) return; Will run a testing for it.