PR c++/84294 - attributes on a function template redeclaration silently discarded

gcc/cp/ChangeLog:

	PR c++/84294
	* decl.c (check_redeclaration_no_default_args): Merge attributes
	specified on redeclarations of the same function template.
	Remove dead code.

gcc/testsuite/ChangeLog:

	PR c++/84294
	* g++.dg/ext/attr-const.C: Remove xfail.
	* g++.dg/ext/attr-malloc-3.C: New test.
	* g++.dg/ext/attr-noinline-3.C: New test.
	* g++.dg/ext/attr-noreturn-3.C: New test.
	* g++.dg/ext/attr-nothrow-3.C: New test.
	* g++.dg/ext/attr-pure.C: Remove xfail.

From-SVN: r258121

9 files changed, 208 insertions, 41 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index d44845b..2d5363c 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2018-03-01  Martin Sebor  <msebor@redhat.com>
+
+	PR c++/84294
+	* decl.c (check_redeclaration_no_default_args): Merge attributes
+	specified on redeclarations of the same function template.
+	Remove dead code.
+
 2018-03-01  Marek Polacek  <polacek@redhat.com>
 	    Jason Merrill  <jason@redhat.com>
 
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index db64d12..735ed5d 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -1355,6 +1355,26 @@ check_redeclaration_no_default_args (tree decl)
       }
 }
 
+/* Merge tree bits that correspond to attributes noreturn, nothrow,
+   const,  malloc, and pure from NEWDECL with those of OLDDECL.  */
+
+static void
+merge_attribute_bits (tree newdecl, tree olddecl)
+{
+  TREE_THIS_VOLATILE (newdecl) |= TREE_THIS_VOLATILE (olddecl);
+  TREE_THIS_VOLATILE (olddecl) |= TREE_THIS_VOLATILE (newdecl);
+  TREE_NOTHROW (newdecl) |= TREE_NOTHROW (olddecl);
+  TREE_NOTHROW (olddecl) |= TREE_NOTHROW (newdecl);
+  TREE_READONLY (newdecl) |= TREE_READONLY (olddecl);
+  TREE_READONLY (olddecl) |= TREE_READONLY (newdecl);
+  DECL_IS_MALLOC (newdecl) |= DECL_IS_MALLOC (olddecl);
+  DECL_IS_MALLOC (olddecl) |= DECL_IS_MALLOC (newdecl);
+  DECL_PURE_P (newdecl) |= DECL_PURE_P (olddecl);
+  DECL_PURE_P (olddecl) |= DECL_PURE_P (newdecl);
+  DECL_UNINLINABLE (newdecl) |= DECL_UNINLINABLE (olddecl);
+  DECL_UNINLINABLE (olddecl) |= DECL_UNINLINABLE (newdecl);
+}
+
 #define GNU_INLINE_P(fn) (DECL_DECLARED_INLINE_P (fn)			\
 			  && lookup_attribute ("gnu_inline",		\
 					       DECL_ATTRIBUTES (fn)))
@@ -2048,6 +2068,8 @@ next_arg:;
 	      DECL_DISREGARD_INLINE_LIMITS (old_result)
 	        |= DECL_DISREGARD_INLINE_LIMITS (new_result);
 	      check_redeclaration_exception_specification (newdecl, olddecl);
+
+	      merge_attribute_bits (new_result, old_result);
 	    }
 	}
 
@@ -2228,18 +2250,7 @@ next_arg:;
 	    |= DECL_LOOPING_CONST_OR_PURE_P (olddecl);
 
 	  if (merge_attr)
-	    {
-	      TREE_THIS_VOLATILE (newdecl) |= TREE_THIS_VOLATILE (olddecl);
-	      TREE_THIS_VOLATILE (olddecl) |= TREE_THIS_VOLATILE (newdecl);
-	      TREE_NOTHROW (newdecl) |= TREE_NOTHROW (olddecl);
-	      TREE_NOTHROW (olddecl) |= TREE_NOTHROW (newdecl);
-	      TREE_READONLY (newdecl) |= TREE_READONLY (olddecl);
-	      TREE_READONLY (olddecl) |= TREE_READONLY (newdecl);
-	      DECL_IS_MALLOC (newdecl) |= DECL_IS_MALLOC (olddecl);
-	      DECL_IS_MALLOC (olddecl) |= DECL_IS_MALLOC (newdecl);
-	      DECL_PURE_P (newdecl) |= DECL_PURE_P (olddecl);
-	      DECL_PURE_P (olddecl) |= DECL_PURE_P (newdecl);
-	    }
+	    merge_attribute_bits (newdecl, olddecl);
 	  else
 	    {
 	      /* Merge the noreturn bit.  */
@@ -2412,32 +2423,15 @@ next_arg:;
 
 	  /* [temp.expl.spec/14] We don't inline explicit specialization
 	     just because the primary template says so.  */
+	  gcc_assert (!merge_attr);
 
-	  if (merge_attr)
-	    {
-	      /* But still keep DECL_DISREGARD_INLINE_LIMITS in sync with
-		 the always_inline attribute.  */
-	      if (DECL_DISREGARD_INLINE_LIMITS (olddecl)
-		  && !DECL_DISREGARD_INLINE_LIMITS (newdecl))
-		{
-		  if (DECL_DECLARED_INLINE_P (newdecl))
-		    DECL_DISREGARD_INLINE_LIMITS (newdecl) = true;
-		  else
-		    DECL_ATTRIBUTES (newdecl)
-		      = remove_attribute ("always_inline",
-					  DECL_ATTRIBUTES (newdecl));
-		}
-	    }
-	  else
-	    {
-	      DECL_DECLARED_INLINE_P (olddecl)
-		= DECL_DECLARED_INLINE_P (newdecl);
+	  DECL_DECLARED_INLINE_P (olddecl)
+	    = DECL_DECLARED_INLINE_P (newdecl);
 
-	      DECL_DISREGARD_INLINE_LIMITS (olddecl)
-		= DECL_DISREGARD_INLINE_LIMITS (newdecl);
+	  DECL_DISREGARD_INLINE_LIMITS (olddecl)
+	    = DECL_DISREGARD_INLINE_LIMITS (newdecl);
 
-	      DECL_UNINLINABLE (olddecl) = DECL_UNINLINABLE (newdecl);
-	    }
+	  DECL_UNINLINABLE (olddecl) = DECL_UNINLINABLE (newdecl);
 	}
       else if (new_defines_function && DECL_INITIAL (olddecl))
 	{
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ef84baf..62fde2d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,13 @@
+2018-03-01  Martin Sebor  <msebor@redhat.com>
+
+	PR c++/84294
+	* g++.dg/ext/attr-const.C: Remove xfail.
+	* g++.dg/ext/attr-malloc-3.C: New test.
+	* g++.dg/ext/attr-noinline-3.C: New test.
+	* g++.dg/ext/attr-noreturn-3.C: New test.
+	* g++.dg/ext/attr-nothrow-3.C: New test.
+	* g++.dg/ext/attr-pure.C: Remove xfail.
+
 2018-03-02  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/70875
diff --git a/gcc/testsuite/g++.dg/ext/attr-const.C b/gcc/testsuite/g++.dg/ext/attr-const.C
index 28f2c6e..17cdae6b 100644
--- a/gcc/testsuite/g++.dg/ext/attr-const.C
+++ b/gcc/testsuite/g++.dg/ext/attr-const.C
@@ -68,6 +68,5 @@ void test_fnone_const ()
   if (i0 != i1)
     templ_none_const_failed ();
 
-  // The following fails (most likely) due to bug 84294.
-  // { dg-final { scan-tree-dump-not "templ_none_const_failed" "optimized" { xfail *-*-* } } }
+  // { dg-final { scan-tree-dump-not "templ_none_const_failed" "optimized" } }
 }
diff --git a/gcc/testsuite/g++.dg/ext/attr-malloc-3.C b/gcc/testsuite/g++.dg/ext/attr-malloc-3.C
index e4470af..5f91ee1 100644
--- a/gcc/testsuite/g++.dg/ext/attr-malloc-3.C
+++ b/gcc/testsuite/g++.dg/ext/attr-malloc-3.C
@@ -91,7 +91,6 @@ void test_templ_none_malloc (void)
   if (p == a)                       // must be false
     templ_none_malloc_failed ();    // should be eliminated
 
-  // The following fails (most likely) due to bug 84294.
   // Verify that the call to templ_none_malloc_failed() is eliminated.
-  // { dg-final { scan-tree-dump-not "templ_none_malloc_failed" "optimized" { xfail *-*-* } } }
+  // { dg-final { scan-tree-dump-not "templ_none_malloc_failed" "optimized" } }
 }
diff --git a/gcc/testsuite/g++.dg/ext/attr-noinline-3.C b/gcc/testsuite/g++.dg/ext/attr-noinline-3.C
new file mode 100644
index 0000000..f3f9856
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/attr-noinline-3.C
@@ -0,0 +1,45 @@
+/*  PR c++/84294 - attributes on a function template redeclaration silently
+    discarded
+    { dg-do compile }
+    { dg-options "-O -fdump-tree-optimized" } */
+
+template <void test ()>
+void test_func ()
+{
+  test ();
+}
+
+int x;
+
+void __attribute__ ((noinline)) func_noinline_none ();
+void func_noinline_none () { x = __LINE__; }
+
+template void test_func<func_noinline_none>();
+// { dg-final { scan-tree-dump-times "func_noinline_none *\\(\\);" 1 "optimized" } }
+
+
+void func_none_noinline ();
+void  __attribute__ ((noinline)) func_none_noinline () { x = __LINE__; }
+
+template void test_func<func_none_noinline>();
+// { dg-final { scan-tree-dump-times "func_none_noinline *\\(\\);" 1 "optimized" } }
+
+
+template <class>
+void __attribute__ ((noinline)) templ_noinline_none () { x = __LINE__; }
+
+template <class>
+void templa_noinline_none ();
+
+template void test_func<templ_noinline_none<int> >();
+// { dg-final { scan-tree-dump-times "templ_noinline_none<int> *\\(\\);" 1 "optimized" } }
+
+
+template <class>
+void templ_none_noinline ();
+
+template <class>
+void  __attribute__ ((noinline)) templ_none_noinline () { x = __LINE__; }
+
+template void test_func<templ_none_noinline<int> >();
+// { dg-final { scan-tree-dump-times "templ_none_noinline<int> *\\(\\);" 1 "optimized" } }
diff --git a/gcc/testsuite/g++.dg/ext/attr-noreturn-3.C b/gcc/testsuite/g++.dg/ext/attr-noreturn-3.C
new file mode 100644
index 0000000..819ed32
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/attr-noreturn-3.C
@@ -0,0 +1,54 @@
+/*  PR c++/84294 - attributes on a function template redeclaration silently
+    discarded
+    { dg-do compile }
+    { dg-options "-O -fdump-tree-optimized" } */
+
+typedef void Func ();
+
+template <Func>
+void fail_func ();
+
+template <Func test>
+int test_func ()
+{
+  test ();
+
+  // Should be eliminated.
+  fail_func<test> ();
+
+  // Expect no -Wreturn type here despite the absence of a return
+  // statement in a non-void function.
+}   // { dg-bogus "\\\[-Wreturn-type]" "bug 84621" { xfail *-*-* } }
+
+void __attribute__ ((noreturn)) func_noreturn_none ();
+void func_noreturn_none ();
+
+template int test_func<func_noreturn_none>();
+
+
+void func_none_noreturn ();
+void  __attribute__ ((noreturn)) func_none_noreturn ();
+
+template int test_func<func_none_noreturn>();
+
+
+template <class>
+void __attribute__ ((noreturn)) templ_noreturn_none ();
+
+template <class>
+void templa_noreturn_none ();
+
+template int test_func<templ_noreturn_none<int> >();
+
+
+template <class>
+void templ_none_noreturn ();
+
+template <class>
+void  __attribute__ ((noreturn)) templ_none_noreturn ();
+
+template int test_func<templ_none_noreturn<int> >();
+
+
+// Verify that calls to fail_func() specializations have been eliminated.
+// { dg-final { scan-tree-dump-not "fail_func" "optimized" } }
diff --git a/gcc/testsuite/g++.dg/ext/attr-nothrow-3.C b/gcc/testsuite/g++.dg/ext/attr-nothrow-3.C
new file mode 100644
index 0000000..ed88826
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/attr-nothrow-3.C
@@ -0,0 +1,60 @@
+/*  PR c++/84294 - attributes on a function template redeclaration silently
+    discarded
+    { dg-do compile }
+    { dg-options "-O -fdump-tree-eh -fdump-tree-optimized" } */
+
+typedef void Func ();
+
+template <Func>
+void fail_func () throw ();
+
+template <Func test>
+void test_func () throw ()
+{
+  try
+    {
+      test ();
+    }
+  catch (...)
+    {
+      // Should be eliminated.
+      fail_func<test> ();
+    }
+}
+
+void __attribute__ ((nothrow)) func_nothrow_none ();
+void func_nothrow_none ();
+
+template void test_func<func_nothrow_none>();
+
+
+void func_none_nothrow ();
+void  __attribute__ ((nothrow)) func_none_nothrow ();
+
+template void test_func<func_none_nothrow>();
+
+
+template <class>
+void __attribute__ ((nothrow)) templ_nothrow_none ();
+
+template <class>
+void templa_nothrow_none ();
+
+template void test_func<templ_nothrow_none<int> >();
+
+
+template <class>
+void templ_none_nothrow ();
+
+template <class>
+void  __attribute__ ((nothrow)) templ_none_nothrow ();
+
+template void test_func<templ_none_nothrow<int> >();
+
+
+// Verify that no exception handling code was emitted.
+// { dg-final { scan-tree-dump-not "eh_dispatch" "eh" } }
+// { dg-final { scan-tree-dump-not "resx" "eh" } }
+
+// Verify that calls to fail_func() specializations have been eliminated.
+// { dg-final { scan-tree-dump-not "fail_func" "optimized" } }
diff --git a/gcc/testsuite/g++.dg/ext/attr-pure.C b/gcc/testsuite/g++.dg/ext/attr-pure.C
index 12532cb..0f25986 100644
--- a/gcc/testsuite/g++.dg/ext/attr-pure.C
+++ b/gcc/testsuite/g++.dg/ext/attr-pure.C
@@ -69,6 +69,5 @@ void test_fnone_const ()
   if (i0 != i1)
     templ_none_const_failed ();
 
-  // The following fails (most likely) due to bug 84294.
-  // { dg-final { scan-tree-dump-not "templ_none_const_failed" "optimized" { xfail *-*-* } } }
+  // { dg-final { scan-tree-dump-not "templ_none_const_failed" "optimized" } }
 }