[gcc r14-2086] Use cvt_op to save intermediate type operand instead of "subtle" vec_dest.

[hongtao Liu <liuhongt@gcc.gnu.org>]

https://gcc.gnu.org/g:1bfe7e5352d1f4ac525317454aca45aa80a517ba

commit r14-2086-g1bfe7e5352d1f4ac525317454aca45aa80a517ba
Author: liuhongt <hongtao.liu@intel.com>
Date:   Sun Jun 25 11:12:29 2023 +0800

    Use cvt_op to save intermediate type operand instead of "subtle" vec_dest.
    
    When there're multiple operands in vec_oprnds0, vec_dest will be
    overwrited to vectype_out, but in multi_step_cvt case, cvt_type is
    expected. It caused an ICE when verify_gimple_in_cfg.
    
    gcc/ChangeLog:
    
            PR tree-optimization/110371
            PR tree-optimization/110018
            * tree-vect-stmts.cc (vectorizable_conversion): Use cvt_op to
            save intermediate type operand instead of "subtle" vec_dest
            for case NONE.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/aarch64/pr110371.c: New test.

Diff:
---
 gcc/testsuite/gcc.target/aarch64/pr110371.c | 20 ++++++++++++++++++++
 gcc/tree-vect-stmts.cc                      | 14 ++++++++++----
 2 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/gcc/testsuite/gcc.target/aarch64/pr110371.c b/gcc/testsuite/gcc.target/aarch64/pr110371.c
new file mode 100644
index 00000000000..444e514e04f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/pr110371.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+typedef struct dest
+{
+  double m[3][3];
+} dest;
+
+typedef struct src
+{
+  int m[3][3];
+} src;
+
+void
+foo (dest *a, src* s)
+{
+  for (int i = 0; i != 3; i++)
+    for (int j = 0; j != 3; j++)
+      a->m[i][j] = s->m[i][j];
+}
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 7d24bbee152..bf61461939b 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -5044,7 +5044,7 @@ vectorizable_conversion (vec_info *vinfo,
 			 gimple **vec_stmt, slp_tree slp_node,
 			 stmt_vector_for_cost *cost_vec)
 {
-  tree vec_dest;
+  tree vec_dest, cvt_op = NULL_TREE;
   tree scalar_dest;
   tree op0, op1 = NULL_TREE;
   loop_vec_info loop_vinfo = dyn_cast <loop_vec_info> (vinfo);
@@ -5569,6 +5569,13 @@ vectorizable_conversion (vec_info *vinfo,
     case NONE:
       vect_get_vec_defs (vinfo, stmt_info, slp_node, ncopies,
 			 op0, &vec_oprnds0);
+      /* vec_dest is intermediate type operand when multi_step_cvt.  */
+      if (multi_step_cvt)
+	{
+	  cvt_op = vec_dest;
+	  vec_dest = vec_dsts[0];
+	}
+
       FOR_EACH_VEC_ELT (vec_oprnds0, i, vop0)
 	{
 	  /* Arguments are ready, create the new vector stmt.  */
@@ -5576,12 +5583,11 @@ vectorizable_conversion (vec_info *vinfo,
 	  if (multi_step_cvt)
 	    {
 	      gcc_assert (multi_step_cvt == 1);
-	      new_stmt = vect_gimple_build (vec_dest, codecvt1, vop0);
-	      new_temp = make_ssa_name (vec_dest, new_stmt);
+	      new_stmt = vect_gimple_build (cvt_op, codecvt1, vop0);
+	      new_temp = make_ssa_name (cvt_op, new_stmt);
 	      gimple_assign_set_lhs (new_stmt, new_temp);
 	      vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
 	      vop0 = new_temp;
-	      vec_dest = vec_dsts[0];
 	    }
 	  new_stmt = vect_gimple_build (vec_dest, code1, vop0);
 	  new_temp = make_ssa_name (vec_dest, new_stmt);