diff options
| author | Jan Beulich <jbeulich@suse.com> | 2024-06-28 08:22:39 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2024-06-28 08:22:39 +0200 |
| commit | 82e06fa803fd00c0640dd4b2078f829f832847fd (patch) | |
| tree | 06a6e2a5444425bb4dde267dba5be9cce1221dad /opcodes/i386-tbl.h | |
| parent | 2a7f257afb4297394ea4239ed97c507d83220dd7 (diff) | |
| download | gdb-82e06fa803fd00c0640dd4b2078f829f832847fd.zip gdb-82e06fa803fd00c0640dd4b2078f829f832847fd.tar.gz gdb-82e06fa803fd00c0640dd4b2078f829f832847fd.tar.bz2 | |
x86/APX: optimize {nf}-form IMUL-by-power-of-2 to SHL
..., for differing only in the resulting EFLAGS, which are left
untouched anyway. That's a shorter encoding, available as long as
certain constraints on operands are met; see code comments. (SHL-by-1
forms may then be subject to further optimization that was introduced
earlier.)
Note that kind of as a side effect this also converts multiplication by
1 to shift by 0, which is a plain move or even no-op anyway. That could
be further shrunk (as could be presence of shifts/rotates by 0 in the
original code as well as a fair set of other {nf}-form insns), yet the
expectation (for now) is that people won't write such code in the first
place.
Diffstat (limited to 'opcodes/i386-tbl.h')
| -rw-r--r-- | opcodes/i386-tbl.h | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/opcodes/i386-tbl.h b/opcodes/i386-tbl.h index 0cd2b89..885fbc4 100644 --- a/opcodes/i386-tbl.h +++ b/opcodes/i386-tbl.h @@ -3452,7 +3452,7 @@ static const insn_template i386_optab[] = 0, 0, 0, 0, 0, 0 } } } }, { MN_imul, 0x69, 3, SPACE_EVEXMAP4, None, { 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 }, { { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 } }, { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }, @@ -3494,7 +3494,7 @@ static const insn_template i386_optab[] = 0, 0, 0, 0, 0, 0 } } } }, { MN_imul, 0x69, 2, SPACE_EVEXMAP4, None, { 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 }, { { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 } }, { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }, @@ -3504,7 +3504,7 @@ static const insn_template i386_optab[] = 0, 0, 0, 0, 0, 0 } } } }, { MN_imulzu, 0x6b, 3, SPACE_EVEXMAP4, None, { 0, 0, 0, 1, 0, 0, 0, 0, 10, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 }, { { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 } }, { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }, @@ -3516,7 +3516,7 @@ static const insn_template i386_optab[] = 0, 0, 0, 0, 0, 0 } } } }, { MN_imulzu, 0x69, 3, SPACE_EVEXMAP4, None, { 0, 0, 0, 1, 0, 0, 0, 0, 10, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 }, { { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 } }, { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }, @@ -3528,7 +3528,7 @@ static const insn_template i386_optab[] = 0, 0, 0, 0, 0, 0 } } } }, { MN_imulzu, 0x6b, 2, SPACE_EVEXMAP4, None, { 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 }, { { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 } }, { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }, @@ -3538,7 +3538,7 @@ static const insn_template i386_optab[] = 0, 0, 0, 0, 0, 0 } } } }, { MN_imulzu, 0x69, 2, SPACE_EVEXMAP4, None, { 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, - 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0 }, { { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0 } }, { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }, |