[binutils-gdb] x86/Intel: SHLD/SHRD have dual meaning

[Jan Beulich]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6ccf16c19d318bae09b7b405825285f7579d820f

commit 6ccf16c19d318bae09b7b405825285f7579d820f
Author: Jan Beulich <jbeulich@suse.com>
Date:   Wed May 29 10:02:01 2024 +0200

    x86/Intel: SHLD/SHRD have dual meaning
    
    Since we uniformly permit D suffixes in Intel mode whenever in AT&T mode
    an L suffix may be used, we need to be consistent with this.
    
    Take the easy route, despite that still leading to an anomaly which is
    also visible from the new testcase:
    
            shld    eax, ecx, 1
            shld    eax, ecx, cl
    
    can mean two things with APX: SHL with a D suffix in NDD EVEX encoding,
    or the traditional SHLD in legacy encoding.

Diff:
---
 gas/config/tc-i386.c                  |  7 +++++--
 gas/testsuite/gas/i386/intel-suffix.d | 34 ++++++++++++++++++++++++++++++
 gas/testsuite/gas/i386/intel-suffix.s | 39 +++++++++++++++++++++++++++++++++++
 gas/testsuite/gas/i386/x86-64.exp     |  1 +
 4 files changed, 79 insertions(+), 2 deletions(-)

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index b1cc06851c5..65d992311b7 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -5392,7 +5392,7 @@ static void init_globals (void)
 }
 
 /* Helper for md_assemble() to decide whether to prepare for a possible 2nd
-   parsing pass. Instead of introducing a rarely use new insn attribute this
+   parsing pass. Instead of introducing a rarely used new insn attribute this
    utilizes a common pattern between affected templates. It is deemed
    acceptable that this will lead to unnecessary pass 2 preparations in a
    limited set of cases.  */
@@ -5404,7 +5404,10 @@ static INLINE bool may_need_pass2 (const insn_template *t)
 	 : (t->opcode_space == SPACE_0F
 	    && (t->base_opcode | 1) == 0xbf)
 	   || (t->opcode_space == SPACE_BASE
-	       && t->base_opcode == 0x63);
+	       && t->base_opcode == 0x63)
+	   || (intel_syntax /* shld / shrd may mean suffixed shl / shr.  */
+	       && t->opcode_space == SPACE_EVEXMAP4
+	       && (t->base_opcode | 8) == 0x2c);
 }
 
 #if defined (OBJ_MAYBE_ELF) || defined (OBJ_ELF)
diff --git a/gas/testsuite/gas/i386/intel-suffix.d b/gas/testsuite/gas/i386/intel-suffix.d
new file mode 100644
index 00000000000..5ac3209e212
--- /dev/null
+++ b/gas/testsuite/gas/i386/intel-suffix.d
@@ -0,0 +1,34 @@
+#objdump: -dw
+#name: Intel syntax w/ suffixes
+
+.*: +file format .*
+
+Disassembly of section \.text:
+0+0 <.*>:
+[ 	]*[a-f0-9]+:	0f a4 c8 01[ 	]+shld   \$0x1,%ecx,%eax
+[ 	]*[a-f0-9]+:	0f a5 c8[ 	]+shld   %cl,%ecx,%eax
+[ 	]*[a-f0-9]+:	d1 e1[ 	]+shl    \$1,%ecx
+[ 	]*[a-f0-9]+:	d3 e1[ 	]+shl    %cl,%ecx
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d1 e1[ 	]+shl    \$1,%ecx,%eax
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d3 e1[ 	]+shl    %cl,%ecx,%eax
+[ 	]*[a-f0-9]+:	d1 e1[ 	]+shl    \$1,%ecx
+[ 	]*[a-f0-9]+:	d3 e1[ 	]+shl    %cl,%ecx
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d1 c1[ 	]+rol    \$1,%ecx,%eax
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d3 c1[ 	]+rol    %cl,%ecx,%eax
+[ 	]*[a-f0-9]+:	d1 c1[ 	]+rol    \$1,%ecx
+[ 	]*[a-f0-9]+:	d3 c1[ 	]+rol    %cl,%ecx
+
+0+[0-9a-f]+ <.*>:
+[ 	]*[a-f0-9]+:	0f ac c8 01[ 	]+shrd   \$0x1,%ecx,%eax
+[ 	]*[a-f0-9]+:	0f ad c8[ 	]+shrd   %cl,%ecx,%eax
+[ 	]*[a-f0-9]+:	d1 e9[ 	]+shr    \$1,%ecx
+[ 	]*[a-f0-9]+:	d3 e9[ 	]+shr    %cl,%ecx
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d1 f9[ 	]+sar    \$1,%ecx,%eax
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d3 f9[ 	]+sar    %cl,%ecx,%eax
+[ 	]*[a-f0-9]+:	d1 f9[ 	]+sar    \$1,%ecx
+[ 	]*[a-f0-9]+:	d3 f9[ 	]+sar    %cl,%ecx
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d1 c9[ 	]+ror    \$1,%ecx,%eax
+[ 	]*[a-f0-9]+:	62 f4 7c 18 d3 c9[ 	]+ror    %cl,%ecx,%eax
+[ 	]*[a-f0-9]+:	d1 c9[ 	]+ror    \$1,%ecx
+[ 	]*[a-f0-9]+:	d3 c9[ 	]+ror    %cl,%ecx
+#pass
diff --git a/gas/testsuite/gas/i386/intel-suffix.s b/gas/testsuite/gas/i386/intel-suffix.s
new file mode 100644
index 00000000000..cc88afabb4a
--- /dev/null
+++ b/gas/testsuite/gas/i386/intel-suffix.s
@@ -0,0 +1,39 @@
+	.intel_syntax noprefix
+	.text
+left:
+	shld	eax, ecx, 1
+	shld	eax, ecx, cl
+
+	shld	ecx, 1
+	shld	ecx, cl
+
+	sald	eax, ecx, 1
+	sald	eax, ecx, cl
+
+	sald	ecx, 1
+	sald	ecx, cl
+
+	rold	eax, ecx, 1
+	rold	eax, ecx, cl
+
+	rold	ecx, 1
+	rold	ecx, cl
+
+right:
+	shrd	eax, ecx, 1
+	shrd	eax, ecx, cl
+
+	shrd	ecx, 1
+	shrd	ecx, cl
+
+	sard	eax, ecx, 1
+	sard	eax, ecx, cl
+
+	sard	ecx, 1
+	sard	ecx, cl
+
+	rord	eax, ecx, 1
+	rord	eax, ecx, cl
+
+	rord	ecx, 1
+	rord	ecx, cl
diff --git a/gas/testsuite/gas/i386/x86-64.exp b/gas/testsuite/gas/i386/x86-64.exp
index ef1ad2dfe8a..8ac7aca1fec 100644
--- a/gas/testsuite/gas/i386/x86-64.exp
+++ b/gas/testsuite/gas/i386/x86-64.exp
@@ -160,6 +160,7 @@ run_dump_test "x86-64-disp-intel"
 run_list_test "disp-imm-64"
 run_dump_test "intel-movs64"
 run_dump_test "intel-cmps64"
+run_dump_test "intel-suffix"
 run_dump_test "x86-64-disp32"
 run_dump_test "rexw"
 run_list_test "x86-64-specific-reg"