bndmk, bndldx, and bndstx assign special meaning to base and index registers, and hence silently swapping the registers should be suppressed. gas/ 2013-10-08 Jan Beulich * tc-i386.c (i386_intel_simplify_register): Suppress base/index swapping for bndmk, bndldx, and bndstx. --- 2013-10-07/gas/config/tc-i386-intel.c +++ 2013-10-07/gas/config/tc-i386-intel.c @@ -291,6 +291,8 @@ i386_intel_simplify_register (expression else if (!intel_state.index) { if (intel_state.in_scale + || current_templates->start->base_opcode == 0xf30f1b /* bndmk */ + || (current_templates->start->base_opcode & ~1) == 0x0f1a /* bnd{ld,st}x */ || i386_regtab[reg_num].reg_type.bitfield.baseindex) intel_state.index = i386_regtab + reg_num; else