Improve -mlfence-after-load
1.Implict load for POP/POPF/POPA/XLATB, no load for Anysize insns
2. Add -mlfence-before-ret=shl/yes, adjust operand size of
or/not/shl according to ret's.
3. Issue warning for REP CMPS/SCAS since they would affect control
flow behavior.
4. Adjust testcases and documents.
gas/Changelog:
* config/tc-i386.c (lfence_before_ret_shl): New member.
(load_insn_p): implict load for POP/POPA/POPF/XLATB, no load
for Anysize insns.
(insert_after_load): Issue warning for REP CMPS/SCAS.
(insert_before_before): Handle iret, Handle
-mlfence-before-ret=shl, Adjust operand size of or/not/shl to ret's,
(md_parse_option): Change -mlfence-before-ret=[none|not|or] to
-mlfence-before-ret=[none/not/or/shl/yes].
Enable -mlfence-before-ret=shl when
-mlfence-beofre-indirect-branch=all and no explict -mlfence-before-ret option.
(md_show_usage): Ditto.
* doc/c-i386.texi: Ditto.
* testsuite/gas/i386/i386.exp: Add new testcases.
* testsuite/gas/i386/lfence-load-b.d: New.
* testsuite/gas/i386/lfence-load-b.e: New.
* testsuite/gas/i386/lfence-load.d: Modified.
* testsuite/gas/i386/lfence-load.e: New.
* testsuite/gas/i386/lfence-load.s: Modified.
* testsuite/gas/i386/lfence-ret-a.d: Modified.
* testsuite/gas/i386/lfence-ret-b.d: Modified.
* testsuite/gas/i386/lfence-ret-c.d: New.
* testsuite/gas/i386/lfence-ret-d.d: New.
* testsuite/gas/i386/lfence-ret.s: Modified.
* testsuite/gas/i386/x86-64-lfence-load-b.d: New.
* testsuite/gas/i386/x86-64-lfence-load.d: Modified.
* testsuite/gas/i386/x86-64-lfence-load.s: Modified.
* testsuite/gas/i386/x86-64-lfence-ret-a.d: Modified.
* testsuite/gas/i386/x86-64-lfence-ret-b.d: Modified.
* testsuite/gas/i386/x86-64-lfence-ret-c.d: New.
* testsuite/gas/i386/x86-64-lfence-ret-d.d: New
* testsuite/gas/i386/x86-64-lfence-ret-e.d: New.
* testsuite/gas/i386/x86-64-lfence-ret.e: New.
* testsuite/gas/i386/x86-64-lfence-ret.s: New.
21 files changed
