tree-optimization/124743 - SLP scheduling of invariant internal ops

The following makes us avoid scheduling invariant internal operations
to random points in the CFG when doing loop vectorization since
in that case the stmt UIDs we use for dominance checks are not
initialized outside of loop bodies.  Instead schedule such
operations by appending to the loop preheader which is where
invariants generally end up for loop vectorization.

	PR tree-optimization/124743
	* tree-vect-slp.cc (vect_schedule_slp_node): Schedule
	loop invariant operations in the loop preheader.

	* gcc.dg/vect/vect-pr124743.c: New testcase.

diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr124743.c b/gcc/testsuite/gcc.dg/vect/vect-pr124743.c
new file mode 100644 (file)
index 0000000..542350a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-pr124743.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O3 -fno-tree-loop-distribute-patterns -fno-tree-loop-distribution -fno-tree-ccp -fno-tree-copy-prop -fno-tree-dse" } */
+
+int a, b, c, d;
+int e(int f, int g) { return g < 0 || g > 1 ? 0 : f >> g; }
+int h(int i) { return a > 1 ? 0 : i << a; }
+int main()
+{
+  for (; b; b++)
+    c = e(h(1), d);
+  return 0;
+}

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 8fa6a740c96c16c0c99041db1dadc54fd50f63b3..9d2d0f98ea8541051ac537dd45978b37e898baea 100644 (file)
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -12081,25 +12081,38 @@ vect_schedule_slp_node (vec_info *vinfo,
          si = gsi_for_stmt (last_stmt);
          gsi_next (&si);
 
-         /* Avoid scheduling internal defs outside of the loop when
-            we might have only implicitly tracked loop mask/len defs.  */
          if (auto loop_vinfo = dyn_cast <loop_vec_info> (vinfo))
-           if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo)
-               || LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo))
-             {
-               gimple_stmt_iterator si2
-                 = gsi_after_labels (LOOP_VINFO_LOOP (loop_vinfo)->header);
-               if ((gsi_end_p (si2)
-                    && (LOOP_VINFO_LOOP (loop_vinfo)->header
-                        != gimple_bb (last_stmt))
-                    && dominated_by_p (CDI_DOMINATORS,
-                                       LOOP_VINFO_LOOP (loop_vinfo)->header,
-                                       gimple_bb (last_stmt)))
-                   || (!gsi_end_p (si2)
-                       && last_stmt != *si2
-                       && vect_stmt_dominates_stmt_p (last_stmt, *si2)))
-                 si = si2;
-             }
+           {
+             /* Avoid scheduling stmts to random places in the CFG, any
+                stmt dominance check we performed is possibly wrong as UIDs
+                are not initialized for all of the function for loop
+                vectorization.  Instead append to the loop preheader.  */
+             if ((LOOP_VINFO_LOOP (loop_vinfo)->header
+                  != gimple_bb (last_stmt))
+                 && dominated_by_p (CDI_DOMINATORS,
+                                    LOOP_VINFO_LOOP (loop_vinfo)->header,
+                                    gimple_bb (last_stmt)))
+               si = gsi_end_bb (loop_preheader_edge
+                                  (LOOP_VINFO_LOOP (loop_vinfo))->src);
+             /* Avoid scheduling internal defs outside of the loop when
+                we might have only implicitly tracked loop mask/len defs.  */
+             if (LOOP_VINFO_FULLY_MASKED_P (loop_vinfo)
+                 || LOOP_VINFO_FULLY_WITH_LENGTH_P (loop_vinfo))
+               {
+                 gimple_stmt_iterator si2
+                   = gsi_after_labels (LOOP_VINFO_LOOP (loop_vinfo)->header);
+                 if ((gsi_end_p (si2)
+                      && (LOOP_VINFO_LOOP (loop_vinfo)->header
+                          != gimple_bb (last_stmt))
+                      && dominated_by_p (CDI_DOMINATORS,
+                                         LOOP_VINFO_LOOP (loop_vinfo)->header,
+                                         gimple_bb (last_stmt)))
+                     || (!gsi_end_p (si2)
+                         && last_stmt != *si2
+                         && vect_stmt_dominates_stmt_p (last_stmt, *si2)))
+                   si = si2;
+               }
+           }
        }
     }