PR target/39558

	* macro.c (cpp_get_token): If macro_to_expand returns NULL
	and used some tokens, add CPP_PADDING before next token.

	* gcc.target/powerpc/altivec-29.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@145297 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 30 insertions, 4 deletions

diff --git a/libcpp/macro.c b/libcpp/macro.c
index 3a20c36ed39..fc70be67403 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -1260,10 +1260,36 @@ cpp_get_token (cpp_reader *pfile)
 
 	  /* Conditional macros require that a predicate be evaluated
 	     first.  */
-	  if (((!(node->flags & NODE_CONDITIONAL))
-	       || (pfile->cb.macro_to_expand
-		   && (node = pfile->cb.macro_to_expand (pfile, result))))
-	      && (ret = enter_macro_context (pfile, node, result)))
+	  if ((node->flags & NODE_CONDITIONAL) != 0)
+	    {
+	      if (pfile->cb.macro_to_expand)
+		{
+		  bool whitespace_after;
+		  const cpp_token *peek_tok = cpp_peek_token (pfile, 0);
+
+		  whitespace_after = (peek_tok->type == CPP_PADDING
+				      || (peek_tok->flags & PREV_WHITE));
+		  node = pfile->cb.macro_to_expand (pfile, result);
+		  if (node)
+		    ret = enter_macro_context (pfile, node, result);
+		  else if (whitespace_after)
+		    {
+		      /* If macro_to_expand hook returned NULL and it
+			 ate some tokens, see if we don't need to add
+			 a padding token in between this and the
+			 next token.  */
+		      peek_tok = cpp_peek_token (pfile, 0);
+		      if (peek_tok->type != CPP_PADDING
+			  && (peek_tok->flags & PREV_WHITE) == 0)
+			_cpp_push_token_context (pfile, NULL,
+						 padding_token (pfile,
+								peek_tok), 1);
+		    }
+		}
+	    }
+	  else
+	    ret = enter_macro_context (pfile, node, result);
+	  if (ret)
  	    {
 	      if (pfile->state.in_directive || ret == 2)
 		continue;