x86: Add -muse-unaligned-vector-move to assembler

Unaligned load/store instructions on aligned memory or register are as
fast as aligned load/store instructions on modern Intel processors.  Add
a command-line option, -muse-unaligned-vector-move, to x86 assembler to
encode encode aligned vector load/store instructions as unaligned
vector load/store instructions.

	* NEWS: Mention -muse-unaligned-vector-move.
	* config/tc-i386.c (use_unaligned_vector_move): New.
	(encode_with_unaligned_vector_move): Likewise.
	(md_assemble): Call encode_with_unaligned_vector_move for
	-muse-unaligned-vector-move.
	(OPTION_MUSE_UNALIGNED_VECTOR_MOVE): New.
	(md_longopts): Add -muse-unaligned-vector-move.
	(md_parse_option): Handle -muse-unaligned-vector-move.
	(md_show_usage): Add -muse-unaligned-vector-move.
	* doc/c-i386.texi: Document -muse-unaligned-vector-move.
	* testsuite/gas/i386/i386.exp: Run unaligned-vector-move and
	x86-64-unaligned-vector-move.
	* testsuite/gas/i386/unaligned-vector-move.d: New file.
	* testsuite/gas/i386/unaligned-vector-move.s: Likewise.
	* testsuite/gas/i386/x86-64-unaligned-vector-move.d: Likewise.

7 files changed, 110 insertions, 0 deletions

diff --git a/gas/NEWS b/gas/NEWS
index 5de205ecd55..de4c61b320d 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -1,5 +1,8 @@
 -*- text -*-
 
+* Add a command-line option, -muse-unaligned-vector-move, for x86 target
+  to encode aligned vector move as unaligned vector move.
+
 * Add support for Cortex-R52+ for Arm.
 
 * Add support for Cortex-A510, Cortex-A710, Cortex-X2 for AArch64.
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 339f9694948..ef30a6bc0e9 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -800,6 +800,9 @@ static unsigned int no_cond_jump_promotion = 0;
 /* Encode SSE instructions with VEX prefix.  */
 static unsigned int sse2avx;
 
+/* Encode aligned vector move as unaligned vector move.  */
+static unsigned int use_unaligned_vector_move;
+
 /* Encode scalar AVX instructions with specific vector length.  */
 static enum
   {
@@ -4073,6 +4076,30 @@ check_hle (void)
     }
 }
 
+/* Encode aligned vector move as unaligned vector move.  */
+
+static void
+encode_with_unaligned_vector_move (void)
+{
+  switch (i.tm.base_opcode)
+    {
+    case 0x28:
+      /* movaps/movapd/vmovaps/vmovapd.  */
+      if (i.tm.opcode_modifier.opcodespace == SPACE_0F
+	  && i.tm.opcode_modifier.opcodeprefix <= PREFIX_0X66)
+	i.tm.base_opcode = 0x10;
+      break;
+    case 0x6f:
+      /* movdqa/vmovdqa/vmovdqa64/vmovdqa32. */
+      if (i.tm.opcode_modifier.opcodespace == SPACE_0F
+	  && i.tm.opcode_modifier.opcodeprefix == PREFIX_0X66)
+	i.tm.opcode_modifier.opcodeprefix = PREFIX_0XF3;
+      break;
+    default:
+      break;
+    }
+}
+
 /* Try the shortest encoding by shortening operand size.  */
 
 static void
@@ -5056,6 +5083,9 @@ md_assemble (char *line)
   if (optimize && !i.no_optimize && i.tm.opcode_modifier.optimize)
     optimize_encoding ();
 
+  if (use_unaligned_vector_move)
+    encode_with_unaligned_vector_move ();
+
   if (!process_suffix ())
     return;
 
@@ -13060,6 +13090,7 @@ const char *md_shortopts = "qnO::";
 #define OPTION_MLFENCE_AFTER_LOAD (OPTION_MD_BASE + 31)
 #define OPTION_MLFENCE_BEFORE_INDIRECT_BRANCH (OPTION_MD_BASE + 32)
 #define OPTION_MLFENCE_BEFORE_RET (OPTION_MD_BASE + 33)
+#define OPTION_MUSE_UNALIGNED_VECTOR_MOVE (OPTION_MD_BASE + 34)
 
 struct option md_longopts[] =
 {
@@ -13081,6 +13112,7 @@ struct option md_longopts[] =
   {"mindex-reg", no_argument, NULL, OPTION_MINDEX_REG},
   {"mnaked-reg", no_argument, NULL, OPTION_MNAKED_REG},
   {"msse2avx", no_argument, NULL, OPTION_MSSE2AVX},
+  {"muse-unaligned-vector-move", no_argument, NULL, OPTION_MUSE_UNALIGNED_VECTOR_MOVE},
   {"msse-check", required_argument, NULL, OPTION_MSSE_CHECK},
   {"moperand-check", required_argument, NULL, OPTION_MOPERAND_CHECK},
   {"mavxscalar", required_argument, NULL, OPTION_MAVXSCALAR},
@@ -13381,6 +13413,10 @@ md_parse_option (int c, const char *arg)
       sse2avx = 1;
       break;
 
+    case OPTION_MUSE_UNALIGNED_VECTOR_MOVE:
+      use_unaligned_vector_move = 1;
+      break;
+
     case OPTION_MSSE_CHECK:
       if (strcasecmp (arg, "error") == 0)
 	sse_check = check_error;
@@ -13796,6 +13832,9 @@ md_show_usage (FILE *stream)
   fprintf (stream, _("\
   -msse2avx               encode SSE instructions with VEX prefix\n"));
   fprintf (stream, _("\
+  -muse-unaligned-vector-move\n\
+                          encode aligned vector move as unaligned vector move\n"));
+  fprintf (stream, _("\
   -msse-check=[none|error|warning] (default: warning)\n\
                           check SSE instructions\n"));
   fprintf (stream, _("\
diff --git a/gas/doc/c-i386.texi b/gas/doc/c-i386.texi
index 99576ef2953..6245d9be82a 100644
--- a/gas/doc/c-i386.texi
+++ b/gas/doc/c-i386.texi
@@ -316,6 +316,12 @@ Valid @var{CPU} values are identical to the processor list of
 This option specifies that the assembler should encode SSE instructions
 with VEX prefix.
 
+@cindex @samp{-muse-unaligned-vector-move} option, i386
+@cindex @samp{-muse-unaligned-vector-move} option, x86-64
+@item -muse-unaligned-vector-move
+This option specifies that the assembler should encode aligned vector
+move as unaligned vector move.
+
 @cindex @samp{-msse-check=} option, i386
 @cindex @samp{-msse-check=} option, x86-64
 @item -msse-check=@var{none}
diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index 680259b1c4e..378e32b39cb 100644
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -272,6 +272,7 @@ if [gas_32_check] then {
     run_dump_test "evex-wig1-intel"
     run_dump_test "evex-no-scale-32"
     run_dump_test "sse2avx"
+    run_dump_test "unaligned-vector-move"
     run_list_test "inval-avx" "-al"
     run_list_test "inval-avx512f" "-al"
     run_list_test "inval-avx512vl" "-al"
@@ -948,6 +949,7 @@ if [gas_64_check] then {
     run_dump_test "x86-64-evex-wig2"
     run_dump_test "evex-no-scale-64"
     run_dump_test "x86-64-sse2avx"
+    run_dump_test "x86-64-unaligned-vector-move"
     run_list_test "x86-64-inval-avx" "-al"
     run_list_test "x86-64-inval-avx512f" "-al"
     run_list_test "x86-64-inval-avx512vl" "-al"
diff --git a/gas/testsuite/gas/i386/unaligned-vector-move.d b/gas/testsuite/gas/i386/unaligned-vector-move.d
new file mode 100644
index 00000000000..d5df2aed58e
--- /dev/null
+++ b/gas/testsuite/gas/i386/unaligned-vector-move.d
@@ -0,0 +1,22 @@
+#as: -muse-unaligned-vector-move
+#objdump: -dw
+#name: i386 (Encode aligned vector move as unaligned vector move)
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+:	0f 10 d1             	movups %xmm1,%xmm2
+ +[a-f0-9]+:	66 0f 10 d1          	movupd %xmm1,%xmm2
+ +[a-f0-9]+:	f3 0f 6f d1          	movdqu %xmm1,%xmm2
+ +[a-f0-9]+:	c5 f8 10 d1          	vmovups %xmm1,%xmm2
+ +[a-f0-9]+:	c5 f9 10 d1          	vmovupd %xmm1,%xmm2
+ +[a-f0-9]+:	c5 fa 6f d1          	vmovdqu %xmm1,%xmm2
+ +[a-f0-9]+:	c5 f8 10 d1          	vmovups %xmm1,%xmm2
+ +[a-f0-9]+:	62 f1 fd 09 10 d1    	vmovupd %xmm1,%xmm2\{%k1\}
+ +[a-f0-9]+:	62 f1 7c 09 10 d1    	vmovups %xmm1,%xmm2\{%k1\}
+ +[a-f0-9]+:	62 f1 7e 09 6f d1    	vmovdqu32 %xmm1,%xmm2\{%k1\}
+ +[a-f0-9]+:	62 f1 fe 09 6f d1    	vmovdqu64 %xmm1,%xmm2\{%k1\}
+#pass
diff --git a/gas/testsuite/gas/i386/unaligned-vector-move.s b/gas/testsuite/gas/i386/unaligned-vector-move.s
new file mode 100644
index 00000000000..b88ae232a38
--- /dev/null
+++ b/gas/testsuite/gas/i386/unaligned-vector-move.s
@@ -0,0 +1,15 @@
+# Encode aligned vector move as unaligned vector move.
+
+	.text
+_start:
+	movaps %xmm1, %xmm2
+	movapd %xmm1, %xmm2
+	movdqa %xmm1, %xmm2
+	vmovaps %xmm1, %xmm2
+	vmovapd %xmm1, %xmm2
+	vmovdqa %xmm1, %xmm2
+	vmovaps %xmm1, %xmm2
+	vmovapd %xmm1, %xmm2{%k1}
+	vmovaps %xmm1, %xmm2{%k1}
+	vmovdqa32 %xmm1, %xmm2{%k1}
+	vmovdqa64 %xmm1, %xmm2{%k1}
diff --git a/gas/testsuite/gas/i386/x86-64-unaligned-vector-move.d b/gas/testsuite/gas/i386/x86-64-unaligned-vector-move.d
new file mode 100644
index 00000000000..cbcd7719bf0
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-unaligned-vector-move.d
@@ -0,0 +1,23 @@
+#source: unaligned-vector-move.s
+#as: -muse-unaligned-vector-move
+#objdump: -dw
+#name: x86-64 (Encode aligned vector move as unaligned vector move)
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <_start>:
+ +[a-f0-9]+:	0f 10 d1             	movups %xmm1,%xmm2
+ +[a-f0-9]+:	66 0f 10 d1          	movupd %xmm1,%xmm2
+ +[a-f0-9]+:	f3 0f 6f d1          	movdqu %xmm1,%xmm2
+ +[a-f0-9]+:	c5 f8 10 d1          	vmovups %xmm1,%xmm2
+ +[a-f0-9]+:	c5 f9 10 d1          	vmovupd %xmm1,%xmm2
+ +[a-f0-9]+:	c5 fa 6f d1          	vmovdqu %xmm1,%xmm2
+ +[a-f0-9]+:	c5 f8 10 d1          	vmovups %xmm1,%xmm2
+ +[a-f0-9]+:	62 f1 fd 09 10 d1    	vmovupd %xmm1,%xmm2\{%k1\}
+ +[a-f0-9]+:	62 f1 7c 09 10 d1    	vmovups %xmm1,%xmm2\{%k1\}
+ +[a-f0-9]+:	62 f1 7e 09 6f d1    	vmovdqu32 %xmm1,%xmm2\{%k1\}
+ +[a-f0-9]+:	62 f1 fe 09 6f d1    	vmovdqu64 %xmm1,%xmm2\{%k1\}
+#pass