From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 28 Jan 2021 15:13:11 +0000 (+0100)
Subject: c++: Fix up handling of register ... asm ("...") vars in templates [PR33661, PR98847]
X-Git-Tag: releases/gcc-10.3.0~341
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cf93f94b3498f3925895fb0bbfd4b64232b9987a;p=thirdparty%2Fgcc.git

c++: Fix up handling of register ... asm ("...") vars in templates [PR33661, PR98847]

As the testcase shows, for vars appearing in templates, we don't attach
the asm spec string to the pattern decls, nor pass it back to cp_finish_decl
during instantiation.

The following patch does that.

2021-01-28  Jakub Jelinek  <jakub@redhat.com>

	PR c++/33661
	PR c++/98847
	* decl.c (cp_finish_decl): For register vars with asmspec in templates
	call set_user_assembler_name and set DECL_HARD_REGISTER.
	* pt.c (tsubst_expr): When instantiating DECL_HARD_REGISTER vars,
	pass asmspec_tree to cp_finish_decl.

	* g++.target/i386/pr98847.C: New test.
---

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index ff9e518a9155..fab98d1ea1f6 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -7665,6 +7665,12 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
 	  retrofit_lang_decl (decl);
 	  SET_DECL_DEPENDENT_INIT_P (decl, true);
 	}
+
+      if (VAR_P (decl) && DECL_REGISTER (decl) && asmspec)
+	{
+	  set_user_assembler_name (decl, asmspec);
+	  DECL_HARD_REGISTER (decl) = 1;
+	}
       return;
     }
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index abef0cdc6638..26907615a514 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -18050,6 +18050,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
 		    bool const_init = false;
 		    unsigned int cnt = 0;
 		    tree first = NULL_TREE, ndecl = error_mark_node;
+		    tree asmspec_tree = NULL_TREE;
 		    maybe_push_decl (decl);
 
 		    if (VAR_P (decl)
@@ -18068,7 +18069,18 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
 		    if (ndecl != error_mark_node)
 		      cp_maybe_mangle_decomp (ndecl, first, cnt);
 
-		    cp_finish_decl (decl, init, const_init, NULL_TREE,
+		    if (VAR_P (decl) && DECL_HARD_REGISTER (pattern_decl))
+		      {
+			tree id = DECL_ASSEMBLER_NAME (pattern_decl);
+			const char *asmspec = IDENTIFIER_POINTER (id);
+			gcc_assert (asmspec[0] == '*');
+			asmspec_tree
+			  = build_string (IDENTIFIER_LENGTH (id) - 1,
+					  asmspec + 1);
+			TREE_TYPE (asmspec_tree) = char_array_type_node;
+		      }
+
+		    cp_finish_decl (decl, init, const_init, asmspec_tree,
 				    constinit_p ? LOOKUP_CONSTINIT : 0);
 
 		    if (ndecl != error_mark_node)
diff --git a/gcc/testsuite/g++.target/i386/pr98847.C b/gcc/testsuite/g++.target/i386/pr98847.C
new file mode 100644
index 000000000000..0a72cccafd6f
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr98847.C
@@ -0,0 +1,20 @@
+// PR c++/98847
+// { dg-do run }
+// { dg-options "-O2 -masm=att" }
+
+template <int N>
+int
+foo ()
+{
+  register int edx asm ("edx");
+  asm ("movl $1234, %%edx" : "=r" (edx));
+  return edx;
+}
+
+int
+main ()
+{
+  if (foo<0> () != 1234)
+    __builtin_abort ();
+  return 0;
+}