PR target/96307: Fix KASAN option checking.

- Disable kasan if target is unsupported and -fasan-shadow-offset= is not
   given, no matter `--param asan-stack=1` is given or not.

 - Moving KASAN option checking testcase to gcc.dg, those testcase could be
   useful for all other target which not support asan.

 - Verifed on riscv and x86.

gcc/ChangeLog:

	PR target/96307
	* toplev.c (process_options): Remove param_asan_stack checking for kasan
	option checking.

gcc/testsuite/ChangeLog:

	PR target/96307
	* gcc.dg/pr96307.c: New.
	* gcc.target/riscv/pr96260.c: Move this test case from here to ...
	* gcc.dg/pr96260.c: ... here.
	* gcc.target/riscv/pr91441.c: Move this test case from here to ...
	* gcc.dg/pr91441.c: ... here.
	* lib/target-supports.exp (check_effective_target_no_fsanitize_address):
	New proc.

gcc/testsuite/gcc.dg/pr91441.c

@@ -1,5 +1,6 @@
 /* PR target/91441 */
 /* { dg-do compile  } */
+/* { dg-require-effective-target no_fsanitize_address }*/
 /* { dg-options "--param asan-stack=1 -fsanitize=kernel-address" } */
 
 int *bar(int *);

gcc/testsuite/gcc.dg/pr96260.c

@@ -1,5 +1,6 @@
 /* PR target/96260 */
 /* { dg-do compile } */
+/* { dg-require-effective-target no_fsanitize_address }*/
 /* { dg-options "--param asan-stack=1 -fsanitize=kernel-address -fasan-shadow-offset=0x100000" } */
 
 int *bar(int *);

gcc/testsuite/gcc.dg/pr96307.c

@@ -0,0 +1,25 @@
+/* PR target/96307 */
+/* { dg-do compile } */
+/* { dg-require-effective-target no_fsanitize_address }*/
+/* { dg-additional-options "-fsanitize=kernel-address --param=asan-instrumentation-with-call-threshold=8" } */
+
+#include <limits.h>
+enum a {test1, test2, test3=INT_MAX};
+enum a a;
+enum a *b;
+
+void reset (void);
+
+void
+t()
+{
+  if (a != test2)
+    __builtin_abort ();
+  if (*b != test2)
+    __builtin_abort ();
+  reset ();
+  if (a != test1)
+    __builtin_abort ();
+  if (*b != test1)
+    __builtin_abort ();
+}

gcc/testsuite/lib/target-supports.exp

@@ -10582,3 +10582,14 @@ proc check_effective_target_movdir { } {
 	}
     } "-mmovdiri -mmovdir64b" ]
 }
+
+# Return 1 if target is not support address sanitize, 1 otherwise.
+
+proc check_effective_target_no_fsanitize_address {} {
+    if ![check_no_compiler_messages fsanitize_address executable {
+	int main (void) { return 0; }
+    }] {
+	return 1;
+    }
+    return 0;
+}

gcc/toplev.c

@@ -1843,7 +1843,6 @@ process_options (void)
 
   if ((flag_sanitize & SANITIZE_KERNEL_ADDRESS)
       && (targetm.asan_shadow_offset == NULL
-	  && param_asan_stack
 	  && !asan_shadow_offset_set_p ()))
     {
       warning_at (UNKNOWN_LOCATION, 0,