tree-optimization/96022 - fix ICE with vectorized shift

This fixes lane extraction for internal def vectorized shifts
with an effective scalar shift operand by always using lane zero
of the first vector stmt.

It also fixes a SLP build issue noticed on the testcase where
we end up building unary vector ops with the only operand built
form scalars which isn't profitable by itself.  The exception
is for stores.

2020-07-02  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/96022
	* tree-vect-stmts.c (vectorizable_shift): Only use the
	first vector stmt when extracting the scalar shift amount.
	* tree-vect-slp.c (vect_build_slp_tree_2): Also build unary
	nodes with all-scalar children from scalars but not stores.
	(vect_analyze_slp_instance): Mark the node not failed.

	* g++.dg/vect/pr96022.cc: New testcase.

diff --git a/gcc/testsuite/g++.dg/vect/pr96022.cc b/gcc/testsuite/g++.dg/vect/pr96022.cc
new file mode 100644 (file)
index 0000000..ca6b276
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/pr96022.cc
@@ -0,0 +1,12 @@
+// { dg-do compile }
+// { dg-additional-options "-O3" }
+
+extern int arr_6[];
+extern char arr_7[] __attribute__((aligned));
+void test(short a, bool, int p8) {
+  for (bool b = 0; b < (bool)p8; b = 1)
+    for (short c = 0; c < 5; c++) {
+      arr_6[c] = (long)2 << a - 30574;
+      arr_7[c] = 0;
+    }
+}

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 532809d2667efd7cd943cf3f61ebf7f62b6bdb33..af123b5ab1debbd10ccd5a9d65030731b99743bc 100644 (file)
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -1530,11 +1530,11 @@ fail:
 
   vect_free_oprnd_info (oprnds_info);
 
-  /* If we have all children of a non-unary child built up from
-     uniform scalars then just throw that away, causing it built up
-     from scalars.  */
-  if (nops > 1
-      && is_a <bb_vec_info> (vinfo)
+  /* If we have all children of a child built up from uniform scalars
+     then just throw that away, causing it built up from scalars.
+     The exception is the SLP node for the vector store.  */
+  if (is_a <bb_vec_info> (vinfo)
+      && !STMT_VINFO_GROUPED_ACCESS (stmt_info)
       /* ???  Rejecting patterns this way doesn't work.  We'd have to
         do extra work to cancel the pattern so the uses see the
         scalar version.  */
@@ -2230,6 +2230,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
              return false;
            }
          /* Fatal mismatch.  */
+         matches[0] = true;
          matches[group_size / const_max_nunits * const_max_nunits] = false;
          vect_free_slp_tree (node, false);
        }

diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index 9b7b04ce2d3994c45a978dd9118549a1731a962c..d68547ed1b509556025b2f3fc7433d684a250d7b 100644 (file)
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -5403,7 +5403,7 @@ vectorizable_shift (vec_info *vinfo,
              if (!op1_vectype)
                op1_vectype = get_vectype_for_scalar_type (vinfo,
                                                           TREE_TYPE (op1),
-                                                          slp_node);
+                                                          slp_op1);
 
               /* Unlike the other binary operators, shifts/rotates have
                  the rhs being int, instead of the same type as the lhs,
@@ -5575,11 +5575,11 @@ vectorizable_shift (vec_info *vinfo,
   /* Arguments are ready.  Create the new vector stmt.  */
   FOR_EACH_VEC_ELT (vec_oprnds0, i, vop0)
     {
-      vop1 = vec_oprnds1[i];
       /* For internal defs where we need to use a scalar shift arg
         extract the first lane.  */
       if (scalar_shift_arg && dt[1] == vect_internal_def)
        {
+         vop1 = vec_oprnds1[0];
          new_temp = make_ssa_name (TREE_TYPE (TREE_TYPE (vop1)));
          gassign *new_stmt
            = gimple_build_assign (new_temp,
@@ -5590,6 +5590,8 @@ vectorizable_shift (vec_info *vinfo,
          vect_finish_stmt_generation (vinfo, stmt_info, new_stmt, gsi);
          vop1 = new_temp;
        }
+      else
+       vop1 = vec_oprnds1[i];
       gassign *new_stmt = gimple_build_assign (vec_dest, code, vop0, vop1);
       new_temp = make_ssa_name (vec_dest, new_stmt);
       gimple_assign_set_lhs (new_stmt, new_temp);