[gas][arm] Add -mwarn-restrict-it

Add a -m{no-}warn-restrict-it option to control IT related warnings in
ARMv8-A and ARMv8-R.  This is disabled by default.

Committed on behalf of Wilco Dijkstra.

gas/ChangeLog:
2019-12-11  Wilco Dijkstra  <wdijkstr@arm.com>

	* config/tc-arm.c (warn_on_restrict_it): Add new variable.
	(it_fsm_post_encode): Check warn_on_restrict_it.
	(arm_option_table): Add -mwarn-restrict-it/-mno-warn-restrict-it.
	* testsuite/gas/arm/armv8-2-fp16-scalar-bad.d: Add -mwarn-restrict-it.
	* testsuite/gas/arm/armv8-2-fp16-scalar-bad-ext.d: Likewise.
	* testsuite/gas/arm/armv8-a-bad.d: Likewise.
	* testsuite/gas/arm/armv8-a-it-bad.d: Likewise.
	* testsuite/gas/arm/armv8-r-bad.d: Likewise.
	* testsuite/gas/arm/armv8-r-it-bad.d: Likewise.
	* testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d: Likewise.
	* testsuite/gas/arm/udf.d: Likewise.

10 files changed, 29 insertions, 8 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 4931c1a..700014d 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,17 @@
+2019-12-11  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	* config/tc-arm.c (warn_on_restrict_it): Add new variable.
+	(it_fsm_post_encode): Check warn_on_restrict_it.
+	(arm_option_table): Add -mwarn-restrict-it/-mno-warn-restrict-it.
+	* testsuite/gas/arm/armv8-2-fp16-scalar-bad.d: Add -mwarn-restrict-it.
+	* testsuite/gas/arm/armv8-2-fp16-scalar-bad-ext.d: Likewise.
+	* testsuite/gas/arm/armv8-a-bad.d: Likewise.
+	* testsuite/gas/arm/armv8-a-it-bad.d: Likewise.
+	* testsuite/gas/arm/armv8-r-bad.d: Likewise.
+	* testsuite/gas/arm/armv8-r-it-bad.d: Likewise.
+	* testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d: Likewise.
+	* testsuite/gas/arm/udf.d: Likewise.
+
 2018-12-11  Jan Beulich  <jbeulich@suse.com>
 
 	* config/tc-i386.c (md_assemble): Extend SSE check conditional.
diff --git a/gas/config/tc-arm.c b/gas/config/tc-arm.c
index c4ffeee..e680f93 100644
--- a/gas/config/tc-arm.c
+++ b/gas/config/tc-arm.c
@@ -154,6 +154,7 @@ static int pic_code	     = FALSE;
 static int fix_v4bx	     = FALSE;
 /* Warn on using deprecated features.  */
 static int warn_on_deprecated = TRUE;
+static int warn_on_restrict_it = FALSE;
 
 /* Understand CodeComposer Studio assembly syntax.  */
 bfd_boolean codecomposer_syntax = FALSE;
@@ -22788,6 +22789,7 @@ it_fsm_post_encode (void)
     handle_pred_state ();
 
   if (now_pred.insn_cond
+      && warn_on_restrict_it
       && !now_pred.warn_deprecated
       && warn_on_deprecated
       && ARM_CPU_HAS_FEATURE (cpu_variant, arm_ext_v8)
@@ -30529,6 +30531,11 @@ struct arm_option_table arm_opts[] =
   {"mwarn-deprecated", NULL, &warn_on_deprecated, 1, NULL},
   {"mno-warn-deprecated", N_("do not warn on use of deprecated feature"),
    &warn_on_deprecated, 0, NULL},
+
+  {"mwarn-restrict-it", N_("warn about performance deprecated IT instructions"
+   " in ARMv8-A and ARMv8-R"), &warn_on_restrict_it, 1, NULL},
+  {"mno-warn-restrict-it", NULL, &warn_on_restrict_it, 0, NULL},
+
   {"mwarn-syms", N_("warn about symbols that match instruction names [default]"), (int *) (& flag_warn_syms), TRUE, NULL},
   {"mno-warn-syms", N_("disable warnings about symobls that match instructions"), (int *) (& flag_warn_syms), FALSE, NULL},
   {NULL, NULL, NULL, 0, NULL}
diff --git a/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad-ext.d b/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad-ext.d
index b98e7cf..d904944 100644
--- a/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad-ext.d
+++ b/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad-ext.d
@@ -1,4 +1,4 @@
 #name: Invalid armv8.2-a scalar fp16
 #source: armv8-2-fp16-scalar-bad.s
-#as: -march=armv8.2-a+fp16
+#as: -march=armv8.2-a+fp16 -mwarn-restrict-it
 #error_output: armv8-2-fp16-scalar-bad.l
diff --git a/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad.d b/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad.d
index 13eb7c7..da625db 100644
--- a/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad.d
+++ b/gas/testsuite/gas/arm/armv8-2-fp16-scalar-bad.d
@@ -1,4 +1,4 @@
 #name: Invalid armv8.2-a scalar fp16
 #source: armv8-2-fp16-scalar-bad.s
-#as: -march=armv8.2-a+fp16 -mfpu=fp-armv8
+#as: -march=armv8.2-a+fp16 -mfpu=fp-armv8 -mwarn-restrict-it
 #error_output: armv8-2-fp16-scalar-bad.l
diff --git a/gas/testsuite/gas/arm/armv8-a-bad.d b/gas/testsuite/gas/arm/armv8-a-bad.d
index 302658d..45109ce 100644
--- a/gas/testsuite/gas/arm/armv8-a-bad.d
+++ b/gas/testsuite/gas/arm/armv8-a-bad.d
@@ -1,4 +1,4 @@
 #name: Invalid v8-a
 #source: armv8-ar-bad.s
-#as: -march=armv8-a
+#as: -march=armv8-a -mwarn-restrict-it
 #error_output: armv8-ar-bad.l
diff --git a/gas/testsuite/gas/arm/armv8-a-it-bad.d b/gas/testsuite/gas/arm/armv8-a-it-bad.d
index 43fc9f1..02788e0 100644
--- a/gas/testsuite/gas/arm/armv8-a-it-bad.d
+++ b/gas/testsuite/gas/arm/armv8-a-it-bad.d
@@ -1,4 +1,4 @@
 #name: Deprecated IT blocks (ARM v8)
 #source: armv8-ar-it-bad.s
 #error_output: armv8-ar-it-bad.l
-#as: -march=armv8-a -mimplicit-it=always
+#as: -march=armv8-a -mimplicit-it=always -mwarn-restrict-it
diff --git a/gas/testsuite/gas/arm/armv8-r-bad.d b/gas/testsuite/gas/arm/armv8-r-bad.d
index 150390b..b643c81 100644
--- a/gas/testsuite/gas/arm/armv8-r-bad.d
+++ b/gas/testsuite/gas/arm/armv8-r-bad.d
@@ -1,4 +1,4 @@
 #name: Invalid v8-r
 #source: armv8-ar-bad.s
-#as: -march=armv8-r
+#as: -march=armv8-r -mwarn-restrict-it
 #error_output: armv8-ar-bad.l
diff --git a/gas/testsuite/gas/arm/armv8-r-it-bad.d b/gas/testsuite/gas/arm/armv8-r-it-bad.d
index 5260ae0..c6f0c5b 100644
--- a/gas/testsuite/gas/arm/armv8-r-it-bad.d
+++ b/gas/testsuite/gas/arm/armv8-r-it-bad.d
@@ -1,4 +1,4 @@
 #name: Deprecated IT blocks (ARM v8)
 #source: armv8-ar-it-bad.s
 #error_output: armv8-ar-it-bad.l
-#as: -march=armv8-r -mimplicit-it=always
+#as: -march=armv8-r -mimplicit-it=always -mwarn-restrict-it
diff --git a/gas/testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d b/gas/testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d
index 8ca576b..41a6cdc 100644
--- a/gas/testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d
+++ b/gas/testsuite/gas/arm/sp-pc-validations-bad-t-v8a.d
@@ -1,4 +1,4 @@
-# as: -march=armv8-a
+# as: -march=armv8-a -mwarn-restrict-it
 # name: Invalid SP and PC operands test - THUMB (v8a)
 # source: sp-pc-validations-bad-t.s
 # error_output: sp-pc-validations-bad-t-v8a.l
diff --git a/gas/testsuite/gas/arm/udf.d b/gas/testsuite/gas/arm/udf.d
index f53a437..a6a021e 100644
--- a/gas/testsuite/gas/arm/udf.d
+++ b/gas/testsuite/gas/arm/udf.d
@@ -1,6 +1,6 @@
 #objdump: -dr --prefix-addresses --show-raw-insn
 #name: UDF
-#as: -march=armv8-a
+#as: -march=armv8-a -mwarn-restrict-it
 #warning_output: udf.l
 #skip: *-*-pe *-*-wince