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[PATCH v2 3/4] x86: adjust segment override prefix emission
- From: Jan Beulich <jbeulich at suse dot com>
- To: "binutils at sourceware dot org" <binutils at sourceware dot org>
- Cc: "H.J. Lu" <hjl dot tools at gmail dot com>
- Date: Fri, 14 Feb 2020 12:44:17 +0100
- Subject: [PATCH v2 3/4] x86: adjust segment override prefix emission
- References: <1fc51e5f-f2d6-67d5-a034-11b32a1e750f@suse.com>
Since we already suppress the prefix altogether when it's the default
one for the chosen addressing mode, let's do so also when instruction
prefix and override specified with the memory operand match. (Note that
insn prefix specified segment overrides never get discarded.)
gas/
2020-02-XX Jan Beulich <jbeulich@suse.com>
* config/tc-i386.c (process_operands): Also skip segment
override prefix emission if it matches an already present one.
* testsuite/gas/i386/prefix32.s: Add double segment override
cases.
* testsuite/gas/i386/prefix32.l: Adjust expectations.
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -7208,11 +7208,12 @@ duplicate:
}
/* If a segment was explicitly specified, and the specified segment
- is not the default, use an opcode prefix to select it. If we
- never figured out what the default segment is, then default_seg
- will be zero at this point, and the specified segment prefix will
- always be used. */
- if ((i.seg[0]) && (i.seg[0] != default_seg))
+ is neither the default nor the one already recorded from a prefix,
+ use an opcode prefix to select it. If we never figured out what
+ the default segment is, then default_seg will be zero at this
+ point, and the specified segment prefix will always be used. */
+ if ((i.seg[0]) && (i.seg[0] != default_seg)
+ && (i.seg[0]->seg_prefix != i.prefix[SEG_PREFIX]))
{
if (!add_prefix (i.seg[0]->seg_prefix))
return 0;
--- a/gas/testsuite/gas/i386/prefix32.l
+++ b/gas/testsuite/gas/i386/prefix32.l
@@ -8,6 +8,7 @@
.*:19: Error: same type of prefix .*
.*:20: Error: data size .* `vaddps'
.*:21: Error: data size .* `vaddpd'
+.*:25: Error: same type of prefix .*
GAS LISTING .*
#...
[ ]*1[ ]+\.text
@@ -33,4 +34,10 @@ GAS LISTING .*
[ ]*20[ ]+data16 vaddps %xmm0, %xmm0, %xmm0
[ ]*21[ ]+data16 vaddpd %xmm0, %xmm0, %xmm0
[ ]*22[ ]*
-[ ]*23[ ]*[\?]+ 0+[ \t]+\.p2align 4,0
+[ ]*23[ ]+\.Lsegment:
+[ ]*24[ ]+\?\?\?\? 368B4500[ ]+ss mov %ss:\(%ebp\), %eax
+[ ]*25[ ]+ss mov %ds:\(%ebp\), %eax
+[ ]*26[ ]+\?\?\?\? 3E8B4500[ ]+ds mov %ss:\(%ebp\), %eax
+[ ]*27[ ]+\?\?\?\? 3E8B4500[ ]+ds mov %ds:\(%ebp\), %eax
+[ ]*28[ ]*
+#pass
--- a/gas/testsuite/gas/i386/prefix32.s
+++ b/gas/testsuite/gas/i386/prefix32.s
@@ -20,4 +20,10 @@ prefix:
data16 vaddps %xmm0, %xmm0, %xmm0
data16 vaddpd %xmm0, %xmm0, %xmm0
+.Lsegment:
+ ss mov %ss:(%ebp), %eax
+ ss mov %ds:(%ebp), %eax
+ ds mov %ss:(%ebp), %eax
+ ds mov %ds:(%ebp), %eax
+
.p2align 4,0