arm: Fix up gcc.target/arm/lto/pr96939_* FAIL

The following patch on top of the
https://gcc.gnu.org/pipermail/gcc-patches/2020-September/553801.html
patch fixes the gcc.target/arm/lto/pr96939_* test in certain ARM
configurations.
As said in the above mentioned patch, the generic code takes care of
saving/restoring TargetVariables or Target Save options, so this just
arranges for the generic code to save those instead of needing the
arm backend to do it manually.

2020-09-14  Jakub Jelinek  <jakub@redhat.com>

	* config/arm/arm.opt (x_arm_arch_string, x_arm_cpu_string,
	x_arm_tune_string): Remove TargetSave entries.
	(march=, mcpu=, mtune=): Add Save keyword.
	* config/arm/arm.c (arm_option_save): Remove.
	(TARGET_OPTION_SAVE): Don't redefine.
	(arm_option_restore): Don't restore x_arm_*_string here.

2 files changed, 3 insertions, 30 deletions

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index f4f32b6..e37cd6f 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -247,8 +247,6 @@ static tree arm_build_builtin_va_list (void);
 static void arm_expand_builtin_va_start (tree, rtx);
 static tree arm_gimplify_va_arg_expr (tree, tree, gimple_seq *, gimple_seq *);
 static void arm_option_override (void);
-static void arm_option_save (struct cl_target_option *, struct gcc_options *,
-			     struct gcc_options *);
 static void arm_option_restore (struct gcc_options *, struct gcc_options *,
 				struct cl_target_option *);
 static void arm_override_options_after_change (void);
@@ -443,9 +441,6 @@ static const struct attribute_spec arm_attribute_table[] =
 #undef TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE
 #define TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE arm_override_options_after_change
 
-#undef TARGET_OPTION_SAVE
-#define TARGET_OPTION_SAVE arm_option_save
-
 #undef TARGET_OPTION_RESTORE
 #define TARGET_OPTION_RESTORE arm_option_restore
 
@@ -3042,24 +3037,11 @@ arm_override_options_after_change (void)
   arm_override_options_after_change_1 (&global_options, &global_options_set);
 }
 
-/* Implement TARGET_OPTION_SAVE.  */
-static void
-arm_option_save (struct cl_target_option *ptr, struct gcc_options *opts,
-		 struct gcc_options */* opts_set */)
-{
-  ptr->x_arm_arch_string = opts->x_arm_arch_string;
-  ptr->x_arm_cpu_string = opts->x_arm_cpu_string;
-  ptr->x_arm_tune_string = opts->x_arm_tune_string;
-}
-
 /* Implement TARGET_OPTION_RESTORE.  */
 static void
 arm_option_restore (struct gcc_options *opts, struct gcc_options *opts_set,
 		    struct cl_target_option *ptr)
 {
-  opts->x_arm_arch_string = ptr->x_arm_arch_string;
-  opts->x_arm_cpu_string = ptr->x_arm_cpu_string;
-  opts->x_arm_tune_string = ptr->x_arm_tune_string;
   arm_configure_build_target (&arm_active_target, ptr, opts_set, false);
 }
 
diff --git a/gcc/config/arm/arm.opt b/gcc/config/arm/arm.opt
index cd3d8e1..f01cd65 100644
--- a/gcc/config/arm/arm.opt
+++ b/gcc/config/arm/arm.opt
@@ -21,15 +21,6 @@
 HeaderInclude
 config/arm/arm-opts.h
 
-TargetSave
-const char *x_arm_arch_string
-
-TargetSave
-const char *x_arm_cpu_string
-
-TargetSave
-const char *x_arm_tune_string
-
 Enum
 Name(tls_type) Type(enum arm_tls_type)
 TLS dialect to use:
@@ -82,7 +73,7 @@ mapcs-stack-check
 Target Report Mask(APCS_STACK) Undocumented
 
 march=
-Target RejectNegative Negative(march=) ToLower Joined Var(arm_arch_string)
+Target Save RejectNegative Negative(march=) ToLower Joined Var(arm_arch_string)
 Specify the name of the target architecture.
 
 ; Other arm_arch values are loaded from arm-tables.opt
@@ -107,7 +98,7 @@ Target Report Mask(CALLER_INTERWORKING)
 Thumb: Assume function pointers may go to non-Thumb aware code.
 
 mcpu=
-Target RejectNegative Negative(mcpu=) ToLower Joined Var(arm_cpu_string)
+Target Save RejectNegative Negative(mcpu=) ToLower Joined Var(arm_cpu_string)
 Specify the name of the target CPU.
 
 mfloat-abi=
@@ -232,7 +223,7 @@ Target Report Mask(TPCS_LEAF_FRAME)
 Thumb: Generate (leaf) stack frames even if not needed.
 
 mtune=
-Target RejectNegative Negative(mtune=) ToLower Joined Var(arm_tune_string)
+Target Save RejectNegative Negative(mtune=) ToLower Joined Var(arm_tune_string)
 Tune code for the given processor.
 
 mprint-tune-info