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| author | Jan Beulich <jbeulich@suse.com> | 2023-02-10 08:10:03 +0100 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2023-02-10 08:10:03 +0100 |
| commit | aa4c197de1682b30d49a2ff163f8623039cb07e0 (patch) | |
| tree | 29114fb6233b8eb1a2428d6efd6dabaae84544f1 /gas | |
| parent | 7fc695286521fb4eec436a651677dfe6550db0f4 (diff) | |
| download | gdb-aa4c197de1682b30d49a2ff163f8623039cb07e0.zip gdb-aa4c197de1682b30d49a2ff163f8623039cb07e0.tar.gz gdb-aa4c197de1682b30d49a2ff163f8623039cb07e0.tar.bz2 | |
x86: simplify a few expressions
Fold adjacent comparisons when, by ORing in a certain mask, the same
effect can be achieved by a single one. In load_insn_p() this extends
to further uses of an already available local variable.
Diffstat (limited to 'gas')
| -rw-r--r-- | gas/config/tc-i386.c | 25 |
1 files changed, 7 insertions, 18 deletions
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index 4994191..511223e 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -4576,8 +4576,7 @@ load_insn_p (void) else if (i.tm.opcode_modifier.opcodespace == SPACE_BASE) { /* test, not, neg, mul, imul, div, idiv. */ - if ((i.tm.base_opcode == 0xf6 || i.tm.base_opcode == 0xf7) - && i.tm.extension_opcode != 1) + if (base_opcode == 0xf7 && i.tm.extension_opcode != 1) return 1; /* inc, dec. */ @@ -4589,13 +4588,12 @@ load_insn_p (void) return 1; /* rol, ror, rcl, rcr, shl/sal, shr, sar. */ - if ((base_opcode == 0xc1 - || (i.tm.base_opcode >= 0xd0 && i.tm.base_opcode <= 0xd3)) + if ((base_opcode == 0xc1 || (base_opcode | 2) == 0xd3) && i.tm.extension_opcode != 6) return 1; /* Check for x87 instructions. */ - if (base_opcode >= 0xd8 && base_opcode <= 0xdf) + if ((base_opcode | 6) == 0xdf) { /* Skip fst, fstp, fstenv, fstcw. */ if (i.tm.base_opcode == 0xd9 @@ -4638,7 +4636,7 @@ load_insn_p (void) { /* bt, bts, btr, btc. */ if (i.tm.base_opcode == 0xba - && (i.tm.extension_opcode >= 4 && i.tm.extension_opcode <= 7)) + && (i.tm.extension_opcode | 3) == 7) return 1; /* cmpxchg8b, cmpxchg16b, xrstors, vmptrld. */ @@ -4673,14 +4671,7 @@ load_insn_p (void) /* add, or, adc, sbb, and, sub, xor, cmp, test, xchg. */ if (i.tm.opcode_modifier.opcodespace == SPACE_BASE - && (base_opcode == 0x1 - || base_opcode == 0x9 - || base_opcode == 0x11 - || base_opcode == 0x19 - || base_opcode == 0x21 - || base_opcode == 0x29 - || base_opcode == 0x31 - || base_opcode == 0x39 + && ((base_opcode | 0x38) == 0x39 || (base_opcode | 2) == 0x87)) return 1; @@ -4708,8 +4699,7 @@ insert_lfence_after (void) chosen by the adversary using an LVI method, then this data-dependent behavior may leak some aspect of the secret. */ - if (((i.tm.base_opcode | 0x1) == 0xa7 - || (i.tm.base_opcode | 0x1) == 0xaf) + if (((i.tm.base_opcode | 0x9) == 0xaf) && i.prefix[REP_PREFIX]) { as_warn (_("`%s` changes flags which would affect control flow behavior"), @@ -4779,8 +4769,7 @@ insert_lfence_before (void) /* Output or/not/shl and lfence before near ret. */ if (lfence_before_ret != lfence_before_ret_none - && (i.tm.base_opcode == 0xc2 - || i.tm.base_opcode == 0xc3)) + && (i.tm.base_opcode | 1) == 0xc3) { if (last_insn.kind != last_insn_other && last_insn.seg == now_seg) |