[gcc(refs/users/glisse/heads/fenv)] Handle dg-require-effective-target fenv in C++

[Marc Glisse <glisse@gcc.gnu.org>]

https://gcc.gnu.org/g:2b20eff5d40e170b59ca90ff31c050f4a57a802e

commit 2b20eff5d40e170b59ca90ff31c050f4a57a802e
Author: Marc Glisse <marc.glisse@inria.fr>
Date:   Thu Aug 6 18:11:30 2020 +0200

    Handle dg-require-effective-target fenv in C++

Diff:
---
 gcc/testsuite/lib/target-supports.exp | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index e79015b4d54..c81637eb2ec 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -9554,9 +9554,18 @@ proc check_effective_target_avr_tiny { } {
 # Return 1 if <fenv.h> is available.
 
 proc check_effective_target_fenv {} {
+    set opts ""
+    if [check_effective_target_c] {
+        append opts "-std=gnu99"
+    }
+    if [check_effective_target_c++] {
+	if { ![check_effective_target_c++11] } {
+	    return 0
+	}
+    }
     return [check_no_compiler_messages fenv object {
 	#include <fenv.h>
-    } [add_options_for_ieee "-std=gnu99"]]
+    } [add_options_for_ieee "$opts"]]
 }
 
 # Return 1 if <fenv.h> is available with all the standard IEEE
@@ -9565,6 +9574,15 @@ proc check_effective_target_fenv {} {
 # exceptions, those need to be specified in the testcases.)
 
 proc check_effective_target_fenv_exceptions {} {
+    set opts ""
+    if [check_effective_target_c] {
+        append opts "-std=gnu99"
+    }
+    if [check_effective_target_c++] {
+	if { ![check_effective_target_c++11] } {
+	    return 0
+	}
+    }
     return [check_runtime fenv_exceptions {
 	#include <fenv.h>
 	#include <stdlib.h>
@@ -9593,7 +9611,7 @@ proc check_effective_target_fenv_exceptions {} {
 	  else
 	    abort ();
 	}
-    } [add_options_for_ieee "-std=gnu99"]]
+    } [add_options_for_ieee "$opts"]]
 }
 
 # Return 1 if -fexceptions is supported.