PR116080: Fix tail call dejagnu checks

- Run the target_effective tail_call checks without optimization to
match the actual test cases.
- Add an extra check for external tail calls to handle targets like
powerpc that cannot tail call between different object files.
This one will also cover templates.

gcc/testsuite/ChangeLog:

	PR testsuite/116080
	* g++.dg/musttail10.C: Use external tail call target check.
	* g++.dg/musttail6.C: Dito.
	* lib/target-supports.exp: Add external_tail_call. Disable
	optimization for tail call checks.

3 files changed, 13 insertions, 5 deletions

diff --git a/gcc/testsuite/g++.dg/musttail10.C b/gcc/testsuite/g++.dg/musttail10.C
index ff7fcc7..bd75aff 100644
--- a/gcc/testsuite/g++.dg/musttail10.C
+++ b/gcc/testsuite/g++.dg/musttail10.C
@@ -8,7 +8,7 @@ double g() { [[gnu::musttail]] return f<int>(); } /* { dg-error "cannot tail-cal
 
 template <class T>
 __attribute__((noinline, noclone, noipa))
-T g1() { [[gnu::musttail]] return f<T>(); } /* { dg-error "target is not able" "" { target powerpc*-*-* } } */
+T g1() { [[gnu::musttail]] return f<T>(); } /* { dg-error "target is not able" "" { target { external_tail_call } } } */
 
 template <class T>
 __attribute__((noinline, noclone, noipa))
diff --git a/gcc/testsuite/g++.dg/musttail6.C b/gcc/testsuite/g++.dg/musttail6.C
index 5c6f694..81f6d9f 100644
--- a/gcc/testsuite/g++.dg/musttail6.C
+++ b/gcc/testsuite/g++.dg/musttail6.C
@@ -1,6 +1,6 @@
 /* { dg-do compile { target { struct_tail_call } } } */
+/* { dg-require-effective-target external_tail_call } */
 /* A lot of architectures will not build this due to PR115606 and PR115607 */
-/* { dg-skip-if "powerpc does not support sibcall to templates" { powerpc*-*-* } } */
 /* { dg-options "-std=gnu++11" } */
 /* { dg-additional-options "-fdelayed-branch" { target sparc*-*-* } } */
 
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index d368251..0a3946e 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -12741,7 +12741,15 @@ proc check_effective_target_tail_call { } {
     return [check_no_messages_and_pattern tail_call ",SIBCALL" rtl-expand {
 	__attribute__((__noipa__)) void foo (void) { }
 	__attribute__((__noipa__)) void bar (void) { foo(); }
-    } {-O2 -fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed dump.
+    } {-fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed dump.
+}
+
+# Return 1 if the target can perform tail-calls for externals
+proc check_effective_target_external_tail_call { } {
+    return [check_no_messages_and_pattern tail_call ",SIBCALL" rtl-expand {
+	extern __attribute__((__noipa__)) void foo (void);
+	__attribute__((__noipa__)) void bar (void) { foo(); }
+    } {-fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed dump.
 }
 
 # Return 1 if the target can perform tail-call optimizations for structures
@@ -12751,9 +12759,9 @@ proc check_effective_target_struct_tail_call { } {
     return [check_no_messages_and_pattern tail_call ",SIBCALL" rtl-expand {
 	// C++
 	struct foo { int a, b; };
-	__attribute__((__noipa__)) struct foo foo (void) { return {}; }
+	extern __attribute__((__noipa__)) struct foo foo (void);
 	__attribute__((__noipa__)) struct foo bar (void) { return foo(); }
-    } {-O2 -fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed dump.
+    } {-fdump-rtl-expand-all}] ;# The "SIBCALL" note requires a detailed dump.
 }
 
 # Return 1 if the target's calling sequence or its ABI