Hi,

With the patch enabling the vectorization of early-breaks, we'd like to allow
bitfield lowering in such loops, which requires the relaxation of allowing
multiple exits when doing so.  In order to avoid a similar issue to PR107275,
the code that rejects loops with certain types of gimple_stmts was hoisted from
'if_convertible_loop_p_1' to 'get_loop_body_in_if_conv_order', to avoid trying
to lower bitfields in loops we are not going to vectorize anyway.

This also ensures 'ifcvt_local_dec' doesn't accidentally remove statements it
shouldn't as it will never come across them.  I made sure to add a comment to
make clear that there is a direct connection between the two and if we were to
enable vectorization of any other gimple statement we should make sure both
handle it.

NOTE: This patch accepted before but never committed because it is a no-op
without the early break patch.   This is a respun version of Andre's patch and
rebased to changes in ifcvt and updated to handle multiple exits.

Bootstrappend and regression tested on aarch64-none-linux-gnu and
x86_64-pc-linux-gnu and no issues.

gcc/ChangeLog:

        * tree-if-conv.cc (if_convertible_loop_p_1): Move check from here ...
        (get_loop_body_if_conv_order): ... to here.
        (if_convertible_loop_p): Remove single_exit check.
        (tree_if_conversion): Move single_exit check to if-conversion part and
        support multiple exits.

gcc/testsuite/ChangeLog:

        * gcc.dg/vect/vect-bitfield-read-1-not.c: New test.
        * gcc.dg/vect/vect-bitfield-read-2-not.c: New test.
        * gcc.dg/vect/vect-bitfield-read-8.c: New test.
        * gcc.dg/vect/vect-bitfield-read-9.c: New test.

Co-Authored-By:  Andre Vieira <andre.simoesdiasvie...@arm.com>

--- inline copy of patch -- 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c
new file mode 100644
index 
0000000000000000000000000000000000000000..0d91067ebb27b1db2b2352975c43bce8b4171e3f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c
@@ -0,0 +1,60 @@
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_long_long } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s {
+    char a : 4;
+};
+
+#define N 32
+#define ELT0 {0}
+#define ELT1 {1}
+#define ELT2 {2}
+#define ELT3 {3}
+#define RES 56
+struct s A[N]
+  = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       switch (ptr[i].a)
+         {
+         case 0:
+           res += ptr[i].a + 1;
+           break;
+         case 1:
+         case 2:
+         case 3:
+           res += ptr[i].a;
+           break;
+         default:
+           return 0;
+         }
+      }
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "Bitfield OK to lower." "ifcvt" } } */
+
+
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c
new file mode 100644
index 
0000000000000000000000000000000000000000..4ac7b3fc0dfd1c9d0b5e94a2ba6a745545577ec1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c
@@ -0,0 +1,49 @@
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_long_long } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s {
+    char a : 4;
+};
+
+#define N 32
+#define ELT0 {0}
+#define ELT1 {1}
+#define ELT2 {2}
+#define ELT3 {3}
+#define RES 48
+struct s A[N]
+  = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       asm volatile ("" ::: "memory");
+       res += ptr[i].a;
+      }
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "Bitfield OK to lower." "ifcvt" } } */
+
+
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c
new file mode 100644
index 
0000000000000000000000000000000000000000..52cfd33d937ae90f3fe9556716c90e098b768ac8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c
@@ -0,0 +1,49 @@
+/* { dg-require-effective-target vect_int } */
+/* { dg-require-effective-target vect_shift } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s { int i : 31; };
+
+#define ELT0 {0}
+#define ELT1 {1}
+#define ELT2 {2}
+#define ELT3 {3}
+#define ELT4 {4}
+#define N 32
+#define RES 25
+struct s A[N]
+  = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT4, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       if (ptr[i].i == 4)
+         return res;
+       res += ptr[i].i;
+      }
+
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "Bitfield OK to lower." "ifcvt" } } */
+
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c
new file mode 100644
index 
0000000000000000000000000000000000000000..ab814698131a5905def181eeed85d8a3c62b924b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c
@@ -0,0 +1,51 @@
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_long_long } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s {
+    unsigned i : 31;
+    char a : 4;
+};
+
+#define N 32
+#define ELT0 {0x7FFFFFFFUL, 0}
+#define ELT1 {0x7FFFFFFFUL, 1}
+#define ELT2 {0x7FFFFFFFUL, 2}
+#define ELT3 {0x7FFFFFFFUL, 3}
+#define ELT4 {0x7FFFFFFFUL, 4}
+#define RES 9
+struct s A[N]
+  = { ELT0, ELT4, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       if (ptr[i].a)
+         return 9;
+       res += ptr[i].a;
+      }
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "Bitfield OK to lower." "ifcvt" } } */
+
diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 
e342532a343a3c066142adeec5fdfaf736a653e5..cdb0fe4c29dfa531e3277925022d127b13ffcc16
 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -586,7 +586,7 @@ add_to_dst_predicate_list (class loop *loop, edge e,
 /* Return true if one of the successor edges of BB exits LOOP.  */
 
 static bool
-bb_with_exit_edge_p (class loop *loop, basic_block bb)
+bb_with_exit_edge_p (const class loop *loop, basic_block bb)
 {
   edge e;
   edge_iterator ei;
@@ -1268,6 +1268,44 @@ get_loop_body_in_if_conv_order (const class loop *loop)
     }
   free (blocks_in_bfs_order);
   BITMAP_FREE (visited);
+
+  /* Go through loop and reject if-conversion or lowering of bitfields if we
+     encounter statements we do not believe the vectorizer will be able to
+     handle.  If adding a new type of statement here, make sure
+     'ifcvt_local_dce' is also able to handle it propertly.  */
+  for (index = 0; index < loop->num_nodes; index++)
+    {
+      basic_block bb = blocks[index];
+      gimple_stmt_iterator gsi;
+
+      bool may_have_nonlocal_labels
+       = bb_with_exit_edge_p (loop, bb) || bb == loop->latch;
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+       switch (gimple_code (gsi_stmt (gsi)))
+         {
+         case GIMPLE_LABEL:
+           if (!may_have_nonlocal_labels)
+             {
+               tree label
+                 = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi)));
+               if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
+                 {
+                   free (blocks);
+                   return NULL;
+                 }
+             }
+           /* Fallthru.  */
+         case GIMPLE_ASSIGN:
+         case GIMPLE_CALL:
+         case GIMPLE_DEBUG:
+         case GIMPLE_COND:
+           gimple_set_uid (gsi_stmt (gsi), 0);
+           break;
+         default:
+           free (blocks);
+           return NULL;
+         }
+    }
   return blocks;
 }
 
@@ -1438,36 +1476,6 @@ if_convertible_loop_p_1 (class loop *loop, 
vec<data_reference_p> *refs)
        exit_bb = bb;
     }
 
-  for (i = 0; i < loop->num_nodes; i++)
-    {
-      basic_block bb = ifc_bbs[i];
-      gimple_stmt_iterator gsi;
-
-      bool may_have_nonlocal_labels
-       = bb_with_exit_edge_p (loop, bb) || bb == loop->latch;
-      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
-       switch (gimple_code (gsi_stmt (gsi)))
-         {
-         case GIMPLE_LABEL:
-           if (!may_have_nonlocal_labels)
-             {
-               tree label
-                 = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi)));
-               if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
-                 return false;
-             }
-           /* Fallthru.  */
-         case GIMPLE_ASSIGN:
-         case GIMPLE_CALL:
-         case GIMPLE_DEBUG:
-         case GIMPLE_COND:
-           gimple_set_uid (gsi_stmt (gsi), 0);
-           break;
-         default:
-           return false;
-         }
-    }
-
   data_reference_p dr;
 
   innermost_DR_map
@@ -1579,14 +1587,6 @@ if_convertible_loop_p (class loop *loop, 
vec<data_reference_p> *refs)
       return false;
     }
 
-  /* More than one loop exit is too much to handle.  */
-  if (!single_exit (loop))
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-       fprintf (dump_file, "multiple exits\n");
-      return false;
-    }
-
   /* If one of the loop header's edge is an exit edge then do not
      apply if-conversion.  */
   FOR_EACH_EDGE (e, ei, loop->header->succs)
@@ -3566,9 +3566,6 @@ tree_if_conversion (class loop *loop, vec<gimple *> 
*preds)
        aggressive_if_conv = true;
     }
 
-  if (!single_exit (loop))
-    goto cleanup;
-
   /* If there are more than two BBs in the loop then there is at least one if
      to convert.  */
   if (loop->num_nodes > 2
@@ -3588,15 +3585,25 @@ tree_if_conversion (class loop *loop, vec<gimple *> 
*preds)
 
   if (loop->num_nodes > 2)
     {
-      need_to_ifcvt = true;
+      /* More than one loop exit is too much to handle.  */
+      if (!single_exit (loop))
+       {
+         if (dump_file && (dump_flags & TDF_DETAILS))
+           fprintf (dump_file, "Can not ifcvt due to multiple exits\n");
+       }
+      else
+       {
+         need_to_ifcvt = true;
 
-      if (!if_convertible_loop_p (loop, &refs) || !dbg_cnt 
(if_conversion_tree))
-       goto cleanup;
+         if (!if_convertible_loop_p (loop, &refs)
+             || !dbg_cnt (if_conversion_tree))
+           goto cleanup;
 
-      if ((need_to_predicate || any_complicated_phi)
-         && ((!flag_tree_loop_vectorize && !loop->force_vectorize)
-             || loop->dont_vectorize))
-       goto cleanup;
+         if ((need_to_predicate || any_complicated_phi)
+             && ((!flag_tree_loop_vectorize && !loop->force_vectorize)
+                 || loop->dont_vectorize))
+           goto cleanup;
+       }
     }
 
   if ((flag_tree_loop_vectorize || loop->force_vectorize)
@@ -3687,7 +3694,8 @@ tree_if_conversion (class loop *loop, vec<gimple *> 
*preds)
      PHIs, those are to be kept in sync with the non-if-converted copy.
      ???  We'll still keep dead stores though.  */
   exit_bbs = BITMAP_ALLOC (NULL);
-  bitmap_set_bit (exit_bbs, single_exit (loop)->dest->index);
+  for (edge exit : get_loop_exit_edges (loop))
+    bitmap_set_bit (exit_bbs, exit->dest->index);
   bitmap_set_bit (exit_bbs, loop->latch->index);
 
   std::pair <tree, tree> *name_pair;




-- 
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c
new file mode 100644
index 
0000000000000000000000000000000000000000..0d91067ebb27b1db2b2352975c43bce8b4171e3f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-1-not.c
@@ -0,0 +1,60 @@
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_long_long } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s {
+    char a : 4;
+};
+
+#define N 32
+#define ELT0 {0}
+#define ELT1 {1}
+#define ELT2 {2}
+#define ELT3 {3}
+#define RES 56
+struct s A[N]
+  = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       switch (ptr[i].a)
+         {
+         case 0:
+           res += ptr[i].a + 1;
+           break;
+         case 1:
+         case 2:
+         case 3:
+           res += ptr[i].a;
+           break;
+         default:
+           return 0;
+         }
+      }
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "Bitfield OK to lower." "ifcvt" } } */
+
+
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c
new file mode 100644
index 
0000000000000000000000000000000000000000..4ac7b3fc0dfd1c9d0b5e94a2ba6a745545577ec1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-2-not.c
@@ -0,0 +1,49 @@
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_long_long } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s {
+    char a : 4;
+};
+
+#define N 32
+#define ELT0 {0}
+#define ELT1 {1}
+#define ELT2 {2}
+#define ELT3 {3}
+#define RES 48
+struct s A[N]
+  = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       asm volatile ("" ::: "memory");
+       res += ptr[i].a;
+      }
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-not "Bitfield OK to lower." "ifcvt" } } */
+
+
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c
new file mode 100644
index 
0000000000000000000000000000000000000000..52cfd33d937ae90f3fe9556716c90e098b768ac8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-8.c
@@ -0,0 +1,49 @@
+/* { dg-require-effective-target vect_int } */
+/* { dg-require-effective-target vect_shift } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s { int i : 31; };
+
+#define ELT0 {0}
+#define ELT1 {1}
+#define ELT2 {2}
+#define ELT3 {3}
+#define ELT4 {4}
+#define N 32
+#define RES 25
+struct s A[N]
+  = { ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT4, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       if (ptr[i].i == 4)
+         return res;
+       res += ptr[i].i;
+      }
+
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "Bitfield OK to lower." "ifcvt" } } */
+
diff --git a/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c 
b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c
new file mode 100644
index 
0000000000000000000000000000000000000000..ab814698131a5905def181eeed85d8a3c62b924b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-bitfield-read-9.c
@@ -0,0 +1,51 @@
+/* { dg-require-effective-target vect_shift } */
+/* { dg-require-effective-target vect_long_long } */
+/* { dg-additional-options { "-fdump-tree-ifcvt-all" } } */
+
+#include <stdarg.h>
+#include "tree-vect.h"
+
+extern void abort(void);
+
+struct s {
+    unsigned i : 31;
+    char a : 4;
+};
+
+#define N 32
+#define ELT0 {0x7FFFFFFFUL, 0}
+#define ELT1 {0x7FFFFFFFUL, 1}
+#define ELT2 {0x7FFFFFFFUL, 2}
+#define ELT3 {0x7FFFFFFFUL, 3}
+#define ELT4 {0x7FFFFFFFUL, 4}
+#define RES 9
+struct s A[N]
+  = { ELT0, ELT4, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3,
+      ELT0, ELT1, ELT2, ELT3, ELT0, ELT1, ELT2, ELT3};
+
+int __attribute__ ((noipa))
+f(struct s *ptr, unsigned n) {
+    int res = 0;
+    for (int i = 0; i < n; ++i)
+      {
+       if (ptr[i].a)
+         return 9;
+       res += ptr[i].a;
+      }
+    return res;
+}
+
+int main (void)
+{
+  check_vect ();
+
+  if (f(&A[0], N) != RES)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "Bitfield OK to lower." "ifcvt" } } */
+
diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 
e342532a343a3c066142adeec5fdfaf736a653e5..cdb0fe4c29dfa531e3277925022d127b13ffcc16
 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -586,7 +586,7 @@ add_to_dst_predicate_list (class loop *loop, edge e,
 /* Return true if one of the successor edges of BB exits LOOP.  */
 
 static bool
-bb_with_exit_edge_p (class loop *loop, basic_block bb)
+bb_with_exit_edge_p (const class loop *loop, basic_block bb)
 {
   edge e;
   edge_iterator ei;
@@ -1268,6 +1268,44 @@ get_loop_body_in_if_conv_order (const class loop *loop)
     }
   free (blocks_in_bfs_order);
   BITMAP_FREE (visited);
+
+  /* Go through loop and reject if-conversion or lowering of bitfields if we
+     encounter statements we do not believe the vectorizer will be able to
+     handle.  If adding a new type of statement here, make sure
+     'ifcvt_local_dce' is also able to handle it propertly.  */
+  for (index = 0; index < loop->num_nodes; index++)
+    {
+      basic_block bb = blocks[index];
+      gimple_stmt_iterator gsi;
+
+      bool may_have_nonlocal_labels
+       = bb_with_exit_edge_p (loop, bb) || bb == loop->latch;
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+       switch (gimple_code (gsi_stmt (gsi)))
+         {
+         case GIMPLE_LABEL:
+           if (!may_have_nonlocal_labels)
+             {
+               tree label
+                 = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi)));
+               if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
+                 {
+                   free (blocks);
+                   return NULL;
+                 }
+             }
+           /* Fallthru.  */
+         case GIMPLE_ASSIGN:
+         case GIMPLE_CALL:
+         case GIMPLE_DEBUG:
+         case GIMPLE_COND:
+           gimple_set_uid (gsi_stmt (gsi), 0);
+           break;
+         default:
+           free (blocks);
+           return NULL;
+         }
+    }
   return blocks;
 }
 
@@ -1438,36 +1476,6 @@ if_convertible_loop_p_1 (class loop *loop, 
vec<data_reference_p> *refs)
        exit_bb = bb;
     }
 
-  for (i = 0; i < loop->num_nodes; i++)
-    {
-      basic_block bb = ifc_bbs[i];
-      gimple_stmt_iterator gsi;
-
-      bool may_have_nonlocal_labels
-       = bb_with_exit_edge_p (loop, bb) || bb == loop->latch;
-      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
-       switch (gimple_code (gsi_stmt (gsi)))
-         {
-         case GIMPLE_LABEL:
-           if (!may_have_nonlocal_labels)
-             {
-               tree label
-                 = gimple_label_label (as_a <glabel *> (gsi_stmt (gsi)));
-               if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
-                 return false;
-             }
-           /* Fallthru.  */
-         case GIMPLE_ASSIGN:
-         case GIMPLE_CALL:
-         case GIMPLE_DEBUG:
-         case GIMPLE_COND:
-           gimple_set_uid (gsi_stmt (gsi), 0);
-           break;
-         default:
-           return false;
-         }
-    }
-
   data_reference_p dr;
 
   innermost_DR_map
@@ -1579,14 +1587,6 @@ if_convertible_loop_p (class loop *loop, 
vec<data_reference_p> *refs)
       return false;
     }
 
-  /* More than one loop exit is too much to handle.  */
-  if (!single_exit (loop))
-    {
-      if (dump_file && (dump_flags & TDF_DETAILS))
-       fprintf (dump_file, "multiple exits\n");
-      return false;
-    }
-
   /* If one of the loop header's edge is an exit edge then do not
      apply if-conversion.  */
   FOR_EACH_EDGE (e, ei, loop->header->succs)
@@ -3566,9 +3566,6 @@ tree_if_conversion (class loop *loop, vec<gimple *> 
*preds)
        aggressive_if_conv = true;
     }
 
-  if (!single_exit (loop))
-    goto cleanup;
-
   /* If there are more than two BBs in the loop then there is at least one if
      to convert.  */
   if (loop->num_nodes > 2
@@ -3588,15 +3585,25 @@ tree_if_conversion (class loop *loop, vec<gimple *> 
*preds)
 
   if (loop->num_nodes > 2)
     {
-      need_to_ifcvt = true;
+      /* More than one loop exit is too much to handle.  */
+      if (!single_exit (loop))
+       {
+         if (dump_file && (dump_flags & TDF_DETAILS))
+           fprintf (dump_file, "Can not ifcvt due to multiple exits\n");
+       }
+      else
+       {
+         need_to_ifcvt = true;
 
-      if (!if_convertible_loop_p (loop, &refs) || !dbg_cnt 
(if_conversion_tree))
-       goto cleanup;
+         if (!if_convertible_loop_p (loop, &refs)
+             || !dbg_cnt (if_conversion_tree))
+           goto cleanup;
 
-      if ((need_to_predicate || any_complicated_phi)
-         && ((!flag_tree_loop_vectorize && !loop->force_vectorize)
-             || loop->dont_vectorize))
-       goto cleanup;
+         if ((need_to_predicate || any_complicated_phi)
+             && ((!flag_tree_loop_vectorize && !loop->force_vectorize)
+                 || loop->dont_vectorize))
+           goto cleanup;
+       }
     }
 
   if ((flag_tree_loop_vectorize || loop->force_vectorize)
@@ -3687,7 +3694,8 @@ tree_if_conversion (class loop *loop, vec<gimple *> 
*preds)
      PHIs, those are to be kept in sync with the non-if-converted copy.
      ???  We'll still keep dead stores though.  */
   exit_bbs = BITMAP_ALLOC (NULL);
-  bitmap_set_bit (exit_bbs, single_exit (loop)->dest->index);
+  for (edge exit : get_loop_exit_edges (loop))
+    bitmap_set_bit (exit_bbs, exit->dest->index);
   bitmap_set_bit (exit_bbs, loop->latch->index);
 
   std::pair <tree, tree> *name_pair;



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