[PATCH] Fix ICE in vectorizable_nonlinear_induction with bitfield.

[liuhongt]

 if (TREE_CODE (init_expr) == INTEGER_CST)
    init_expr = fold_convert (TREE_TYPE (vectype), init_expr);
  else
    gcc_assert (tree_nop_conversion_p (TREE_TYPE (vectype),
                                       TREE_TYPE (init_expr)));

and init_expr is a 24 bit integer type while vectype has 32bit components.

The "fix" is to bail out instead of asserting.

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk?(and backport to GCC-13)

gcc/ChangeLog:

        PR tree-optimization/112496
        * tree-vect-loop.cc (vectorizable_nonlinear_induction): Return
        false when !tree_nop_conversion_p (TREE_TYPE (vectype),
        TREE_TYPE (init_expr).

gcc/testsuite/ChangeLog:

        * gcc.target/i386/pr112496.c: New test.
---
 gcc/testsuite/gcc.target/i386/pr112496.c |  7 +++++++
 gcc/tree-vect-loop.cc                    | 13 ++++++++++---
 2 files changed, 17 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr112496.c

diff --git a/gcc/testsuite/gcc.target/i386/pr112496.c 
b/gcc/testsuite/gcc.target/i386/pr112496.c
new file mode 100644
index 00000000000..c478fda9cce
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr112496.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+struct T { int x : 24; } v;
+void f1(int x) {
+  while (v.x - ((v.x <<= 1) - v.x)) ;
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 1304b7ece79..75d69bbc30e 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -9429,9 +9429,16 @@ vectorizable_nonlinear_induction (loop_vec_info 
loop_vinfo,
 
   if (TREE_CODE (init_expr) == INTEGER_CST)
     init_expr = fold_convert (TREE_TYPE (vectype), init_expr);
-  else
-    gcc_assert (tree_nop_conversion_p (TREE_TYPE (vectype),
-                                      TREE_TYPE (init_expr)));
+  else if (!tree_nop_conversion_p (TREE_TYPE (vectype), TREE_TYPE (init_expr)))
+    {
+      /* INIT_EXPR could be a bit_field, bail out for such case.  */
+      if (dump_enabled_p ())
+       dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+                        "nonlinear induction vectorization failed:"
+                        " component type of vectype is not a nop conversion"
+                        " from type of init_expr.\n");
+      return false;
+    }
 
   switch (induction_type)
     {
-- 
2.31.1