[PATCH] PR c/110699: Defend against error_mark_node in gimplify.cc.

[Roger Sayle]

This patch resolves PR c/110699, an ICE-after-error regression, by adding
a check that the array type isn't error_mark_node in gimplify_compound_lval.

This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, both with and without --target_board=unix{-m32}
with no new failures.  Ok for mainline?


2023-07-19  Roger Sayle  <ro...@nextmovesoftware.com>

gcc/ChangeLog
        PR c/110699
        * gimplify.cc (gimplify_compound_lval):  For ARRAY_REF and
        ARRAY_RANGE_REF return GS_ERROR if the array's type is
        error_mark_node.

gcc/testsuite/ChangeLog
        PR c/110699
        * gcc.dg/pr110699.c: New test case.


Cheers,
Roger
--


diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index 36e5df0..4f40b24 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -3211,6 +3211,9 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, 
gimple_seq *post_p,
 
       if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
        {
+         if (TREE_TYPE (TREE_OPERAND (t, 0)) == error_mark_node)
+           return GS_ERROR;
+
          /* Deal with the low bound and element type size and put them into
             the ARRAY_REF.  If these values are set, they have already been
             gimplified.  */
diff --git a/gcc/testsuite/gcc.dg/pr110699.c b/gcc/testsuite/gcc.dg/pr110699.c
new file mode 100644
index 0000000..be77613
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr110699.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+typedef __attribute__((__vector_size__(64))) int T;
+
+void f(void) {
+  extern char a[64], b[64];  /* { dg-message "previous" "note" } */
+  void *p = a;
+  T q = *(T *)&b[0];
+}
+
+void g() {
+  extern char b;  /* { dg-error "conflicting types" } */
+}