From 4e3be89fdaa5fb1647e6fb91c6f2fae47d923f90 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Fri, 2 Feb 2024 08:27:16 +0100 Subject: [PATCH] x86: move Q-suffix-to-REX.W translation logic By pulling it ahead of the SHORT_MNEM_SUFFIX case label we can drop a part of another conditional there. While moving, also drop a pointless check: With QWORD_MNEM_SUFFIX, register operands of XCHG necessarily have both been 64-bit ones. --- gas/config/tc-i386.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index e091b864e03..3e1811a092d 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -9464,13 +9464,31 @@ process_suffix (void) else i.tm.base_opcode |= 1; } + + /* Set mode64 for an operand. */ + if (i.suffix == QWORD_MNEM_SUFFIX) + { + if (flag_code == CODE_64BIT + && !i.tm.opcode_modifier.norex64 + && !i.tm.opcode_modifier.vexw + /* Special case for xchg %rax,%rax. It is NOP and doesn't + need rex64. */ + && ! (i.operands == 2 + && i.tm.base_opcode == 0x90 + && i.tm.opcode_space == SPACE_BASE + && i.types[0].bitfield.instance == Accum + && i.types[1].bitfield.instance == Accum)) + i.rex |= REX_W; + + break; + } + /* fall through */ case SHORT_MNEM_SUFFIX: /* Now select between word & dword operations via the operand size prefix, except for instructions that will ignore this prefix anyway. */ - if (i.suffix != QWORD_MNEM_SUFFIX - && i.tm.opcode_modifier.mnemonicsize != IGNORESIZE + if (i.tm.opcode_modifier.mnemonicsize != IGNORESIZE && !i.tm.opcode_modifier.floatmf && (!is_any_vex_encoding (&i.tm) || i.tm.opcode_space == SPACE_EVEXMAP4) @@ -9494,21 +9512,6 @@ process_suffix (void) return 0; } - /* Set mode64 for an operand. */ - if (i.suffix == QWORD_MNEM_SUFFIX - && flag_code == CODE_64BIT - && !i.tm.opcode_modifier.norex64 - && !i.tm.opcode_modifier.vexw - /* Special case for xchg %rax,%rax. It is NOP and doesn't - need rex64. */ - && ! (i.operands == 2 - && i.tm.base_opcode == 0x90 - && i.tm.opcode_space == SPACE_BASE - && i.types[0].bitfield.instance == Accum - && i.types[0].bitfield.qword - && i.types[1].bitfield.instance == Accum)) - i.rex |= REX_W; - break; case 0: -- 2.39.5