[PATCH] c++: mangle noexcept-expr [PR70790]

[Patrick Palka via Gcc-patches]

This implements noexcept-expr mangling (and demangling) as per the
Itanium ABI.

Bootstrapped and regtested on x86_64-pc-linux-gnu, does this
look OK for trunk?

        PR c++/70790

gcc/cp/ChangeLog:

        * mangle.cc (write_expression): Handle NOEXCEPT_EXPR.

libiberty/ChangeLog:

        * cp-demangle.c (cplus_demangle_operators): Add the noexcept
        operator.
        * testsuite/demangle-expected: Test noexcept operator
        demangling.

gcc/testsuite/ChangeLog:

        * g++.dg/abi/mangle78.C: New test.
---
 gcc/cp/mangle.cc                      |  5 +++++
 gcc/testsuite/g++.dg/abi/mangle78.C   | 14 ++++++++++++++
 libiberty/cp-demangle.c               |  1 +
 libiberty/testsuite/demangle-expected |  3 +++
 4 files changed, 23 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/abi/mangle78.C

diff --git a/gcc/cp/mangle.cc b/gcc/cp/mangle.cc
index 826c5e76c1d..7dab4e62bc9 100644
--- a/gcc/cp/mangle.cc
+++ b/gcc/cp/mangle.cc
@@ -3402,6 +3402,11 @@ write_expression (tree expr)
       else
        write_string ("tr");
     }
+  else if (code == NOEXCEPT_EXPR)
+    {
+      write_string ("nx");
+      write_expression (TREE_OPERAND (expr, 0));
+    }
   else if (code == CONSTRUCTOR)
     {
       bool braced_init = BRACE_ENCLOSED_INITIALIZER_P (expr);
diff --git a/gcc/testsuite/g++.dg/abi/mangle78.C 
b/gcc/testsuite/g++.dg/abi/mangle78.C
new file mode 100644
index 00000000000..a3647711604
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/mangle78.C
@@ -0,0 +1,14 @@
+// PR c++/70790
+// { dg-do compile { target c++11 } }
+
+template<bool B>
+struct A { };
+
+template<class T>
+void f(A<noexcept(T())>);
+
+int main() {
+  f<int>({});
+}
+
+// { dg-final { scan-assembler "_Z1fIiEv1AIXnxcvT__EEE" } }
diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index f2b36bcad68..341c66db919 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -1947,6 +1947,7 @@ const struct demangle_operator_info 
cplus_demangle_operators[] =
   { "ng", NL ("-"),         1 },
   { "nt", NL ("!"),         1 },
   { "nw", NL ("new"),       3 },
+  { "nx", NL ("noexcept"),  1 },
   { "oR", NL ("|="),        2 },
   { "oo", NL ("||"),        2 },
   { "or", NL ("|"),         2 },
diff --git a/libiberty/testsuite/demangle-expected 
b/libiberty/testsuite/demangle-expected
index d9bc7ed4b1f..7195cc39c19 100644
--- a/libiberty/testsuite/demangle-expected
+++ b/libiberty/testsuite/demangle-expected
@@ -1659,3 +1659,6 @@ auto f()::{lambda<typename $T0>(X<$T0>*, 
X<int>*)#1}::operator()<char>(X<char>*,
 
 _ZZN1XIiE1FEvENKUliE_clEi
 X<int>::F()::{lambda(int)#1}::operator()(int) const
+
+_Z1fIiEv1AIXnxcvT__EEE
+void f<int>(A<noexcept((int)())>)
-- 
2.41.0.rc0.4.g004e0f790f