[PATCH] c++: Fix handling of internal fn calls in statement expressions [PR94385]

[Jakub Jelinek via Gcc-patches]

Hi!

The following testcase ICEs, because the FE when processing the statement
expression changes the .VEC_CONVERT internal fn CALL_EXPR into .PHI call.
That is because the internal fn call is recorded in the base.u.ifn
field, which overlaps base.u.bits.lang_flag_1 which is used for
STMT_IS_FULL_EXPR_P, so this essentially does ifn |= 2 on little-endian.
STMT_IS_FULL_EXPR_P bit is used in:
cp-gimplify.c-  if (STATEMENT_CODE_P (code))
cp-gimplify.c-    {
cp-gimplify.c-      saved_stmts_are_full_exprs_p = stmts_are_full_exprs_p ();
cp-gimplify.c-      current_stmt_tree ()->stmts_are_full_exprs_p
cp-gimplify.c:        = STMT_IS_FULL_EXPR_P (*expr_p);
cp-gimplify.c-    }
and
pt.c-  if (STATEMENT_CODE_P (TREE_CODE (t)))
pt.c:    current_stmt_tree ()->stmts_are_full_exprs_p = STMT_IS_FULL_EXPR_P (t);
so besides being wrong on some other codes, it actually isn't beneficial at
all to set it on anything else, so the following patch restricts it to
trees with STATEMENT_CODE_P TREE_CODE.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2020-03-29  Jakub Jelinek  <ja...@redhat.com>

        PR c++/94385
        * semantics.c (add_stmt): Only set STMT_IS_FULL_EXPR_P on trees with
        STATEMENT_CODE_P code.

--- gcc/cp/semantics.c.jj       2020-03-28 10:19:14.898349472 +0100
+++ gcc/cp/semantics.c  2020-03-29 00:02:40.648258781 +0100
@@ -380,7 +380,8 @@ add_stmt (tree t)
 
       /* When we expand a statement-tree, we must know whether or not the
         statements are full-expressions.  We record that fact here.  */
-      STMT_IS_FULL_EXPR_P (t) = stmts_are_full_exprs_p ();
+      if (STATEMENT_CODE_P (TREE_CODE (t)))
+       STMT_IS_FULL_EXPR_P (t) = stmts_are_full_exprs_p ();
     }
 
   if (code == LABEL_EXPR || code == CASE_LABEL_EXPR)
--- gcc/testsuite/c-c++-common/pr94385.c.jj     2020-03-29 00:05:23.402823607 
+0100
+++ gcc/testsuite/c-c++-common/pr94385.c        2020-03-29 00:05:08.149051828 
+0100
@@ -0,0 +1,12 @@
+/* PR c++/94385 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+typedef int V __attribute__((__vector_size__(16)));
+typedef float W __attribute__((__vector_size__(16)));
+
+void
+foo (W *x, V *y)
+{
+  *y = (({ __builtin_convertvector (*x, V); }));
+}

        Jakub