Bail out early during gimplify_asm_expr [PR121391]

In case an asm operand is an error node, constraints etc. are still
validated.  Furthermore, all other operands are gimplified, although an
error is returned in the end anyway.  For hard register constraints an
operand is required in order to determine the mode from which the number
of registers follows.  Therefore, instead of adding extra guards, bail
out early.

gcc/ChangeLog:

	PR middle-end/121391
	* gimplify.cc (gimplify_asm_expr): In case an asm operand is an
	error node, bail out early.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr121391-1.c: New test.
	* gcc.dg/pr121391-2.c: New test.

3 files changed, 28 insertions, 8 deletions

diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index ca1fa21..9009683 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -7930,6 +7930,8 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
       bool ok;
       size_t constraint_len;
 
+      if (error_operand_p (TREE_VALUE (link)))
+	return GS_ERROR;
       link_next = TREE_CHAIN (link);
 
       oconstraints[i]
@@ -7951,10 +7953,9 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
       /* If we can't make copies, we can only accept memory.
 	 Similarly for VLAs.  */
       tree outtype = TREE_TYPE (TREE_VALUE (link));
-      if (outtype != error_mark_node
-	  && (TREE_ADDRESSABLE (outtype)
-	      || !COMPLETE_TYPE_P (outtype)
-	      || !tree_fits_poly_uint64_p (TYPE_SIZE_UNIT (outtype))))
+      if (TREE_ADDRESSABLE (outtype)
+	  || !COMPLETE_TYPE_P (outtype)
+	  || !tree_fits_poly_uint64_p (TYPE_SIZE_UNIT (outtype)))
 	{
 	  if (allows_mem)
 	    allows_reg = 0;
@@ -8155,6 +8156,8 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
   int input_num = 0;
   for (link = ASM_INPUTS (expr); link; ++input_num, ++i, link = link_next)
     {
+      if (error_operand_p (TREE_VALUE (link)))
+	return GS_ERROR;
       link_next = TREE_CHAIN (link);
       constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
       reg_info.operand = TREE_VALUE (link);
@@ -8169,10 +8172,9 @@ gimplify_asm_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 
       /* If we can't make copies, we can only accept memory.  */
       tree intype = TREE_TYPE (TREE_VALUE (link));
-      if (intype != error_mark_node
-	  && (TREE_ADDRESSABLE (intype)
-	      || !COMPLETE_TYPE_P (intype)
-	      || !tree_fits_poly_uint64_p (TYPE_SIZE_UNIT (intype))))
+      if (TREE_ADDRESSABLE (intype)
+	  || !COMPLETE_TYPE_P (intype)
+	  || !tree_fits_poly_uint64_p (TYPE_SIZE_UNIT (intype)))
 	{
 	  if (allows_mem)
 	    allows_reg = 0;
diff --git a/gcc/testsuite/gcc.dg/pr121391-1.c b/gcc/testsuite/gcc.dg/pr121391-1.c
new file mode 100644
index 0000000..6a01521
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr121391-1.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target aarch64*-*-* arm*-*-* powerpc*-*-* s390*-*-* x86_64-*-* } } */
+
+/* For the non existing variable we are faced with an error mark node during
+   gimplify_asm_expr().  */
+
+void test (void)
+{
+  __asm__ __volatile__ ("" : "={2}" (non_existing_var)); /* { dg-error {'non_existing_var' undeclared} } */
+}
diff --git a/gcc/testsuite/gcc.dg/pr121391-2.c b/gcc/testsuite/gcc.dg/pr121391-2.c
new file mode 100644
index 0000000..c03f0ab
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr121391-2.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target aarch64*-*-* arm*-*-* powerpc*-*-* s390*-*-* x86_64-*-* } } */
+
+/* For the non existing variable we are faced with an error mark node during
+   gimplify_asm_expr().  */
+
+void test (void)
+{
+  __asm__ __volatile__ ("" :: "{2}" (non_existing_var)); /* { dg-error {'non_existing_var' undeclared} } */
+}