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| author | Jan Beulich <jbeulich@suse.com> | 2021-06-10 12:39:08 +0200 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2021-06-10 12:39:08 +0200 |
| commit | 7772f16880afc636b43184f443d173ec93302242 (patch) | |
| tree | df018a13c360d06797e72505d1acbb995b55c1dc /gas/config | |
| parent | 4bdd1a062098b6ba5f59ce1fcd15ef654df648b2 (diff) | |
| download | gdb-7772f16880afc636b43184f443d173ec93302242.zip gdb-7772f16880afc636b43184f443d173ec93302242.tar.gz gdb-7772f16880afc636b43184f443d173ec93302242.tar.bz2 | |
x86: suppress LEA optimization in a specific 16-bit case
In 16-bit mode a 16-bit address size LEA with a 16-bit displacement and
a 32-bit destination is shorter to encode than the corresponding MOV.
Commit fe134c656991 ("x86: optimize LEA")'s promise was to only do the
transformation when the encoding size wouldn't grow, i.e. it did go a
little too far. Restrict this specific case of the transformation to
-O2.
Diffstat (limited to 'gas/config')
| -rw-r--r-- | gas/config/tc-i386.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index 80b7098..47c12b9 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -4140,6 +4140,13 @@ optimize_encoding (void) ? i.op[1].regs->reg_type.bitfield.dword : i.op[1].regs->reg_type.bitfield.word))) return; + /* In 16-bit mode converting LEA with 16-bit addressing and a 32-bit + destination is going to grow encoding size. */ + else if (flag_code == CODE_16BIT + && (optimize <= 1 || optimize_for_space) + && !i.prefix[ADDR_PREFIX] + && i.op[1].regs->reg_type.bitfield.dword) + return; else { i.tm.base_opcode = 0xb8; |