@@ -1,3 +1,13 @@
+2016-06-13 Jeff Law <law@redhat.com>
+
+ PR tree-optimization/71403
+ * tree-ssa-threadbackward.c
+ (convert_and_register_jump_thread_path): No longer accept reference
+ to path. Do not pop items off the path anymore.
+ (fsm_find_control_statement_thread_paths): Do not allow threading
+ to a deeper loop nest. Pop the last item off the path here rather
+ than in convert_and_register_jump_thread_path.
+
2016-06-13 Kelvin Nilsen <kelvin@gcc.gnu.org>
* config/rs6000/rs6000.h (RS6000_BTM_COMMON): Add the
@@ -1,3 +1,10 @@
+2016-06-13 Jeff Law <law@redhat.com>
+
+ PR tree-optimization/71403
+ * c-c++-common/ubsan/pr71403-1.c: New test.
+ * c-c++-common/ubsan/pr71403-2.c: New test.
+ * c-c++-common/ubsan/pr71403-3.c: New test.
+
2016-06-13 Jakub Jelinek <jakub@redhat.com>
PR middle-end/71478
new file mode 100644
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fsanitize=unreachable" } */
+
+char a = -97;
+int b, c, d, e;
+
+int
+main ()
+{
+ int g = d, h = 0, i = 1;
+ for (; h < 3; h++)
+ {
+ if (g > -1)
+ {
+ int j;
+ g = j = 0;
+ for (; j < 5; j++)
+ L1:
+ if (!i)
+ goto L1;
+ a = e;
+ }
+ else
+ i = 0;
+ }
+ b = c / ~(a | 114);
+ __builtin_exit (0);
+}
new file mode 100644
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fsanitize=unreachable" } */
+
+char a, c;
+short b;
+
+int
+main ()
+{
+ unsigned d = 0;
+ int e = 1;
+ for (a = 0; a < 2; a++)
+ {
+ if (e)
+ c--;
+ for (; d < 2; d++)
+ for (b = 0; b; b++)
+ ;
+ e = 0;
+ }
+ __builtin_exit (0);
+}
new file mode 100644
@@ -0,0 +1,31 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fsanitize=unreachable" } */
+
+
+int a, b, c, d;
+
+void
+fn1 ()
+{
+ for (c = 0; c < 2; c++)
+ {
+ int e, f = 1;
+ for (e = 0; e < 2; e++)
+ {
+ if (!f)
+ return;
+ for (d = 0; d; d++)
+ f = b;
+ }
+ }
+}
+
+int
+main ()
+{
+ for (; a < 1; a++)
+ {
+ fn1 ();
+ }
+ __builtin_exit (0);
+}
@@ -378,7 +378,7 @@ profitable_jump_thread_path (vec<basic_block, va_gc> *&path,
register the path. */
static void
-convert_and_register_jump_thread_path (vec<basic_block, va_gc> *&path,
+convert_and_register_jump_thread_path (vec<basic_block, va_gc> *path,
edge taken_edge)
{
vec<jump_thread_edge *> *jump_thread_path = new vec<jump_thread_edge *> ();
@@ -402,9 +402,6 @@ convert_and_register_jump_thread_path (vec<basic_block, va_gc> *&path,
register_jump_thread (jump_thread_path);
--max_threaded_paths;
-
- /* Remove BBI from the path. */
- path->pop ();
}
/* We trace the value of the SSA_NAME NAME back through any phi nodes looking
@@ -459,6 +456,9 @@ fsm_find_control_statement_thread_paths (tree name,
seen_loop_phi = true;
}
+ if (bb_loop_depth (last_bb_in_path) > bb_loop_depth (var_bb))
+ return;
+
/* Following the chain of SSA_NAME definitions, we jumped from a definition in
LAST_BB_IN_PATH to a definition in VAR_BB. When these basic blocks are
different, append to PATH the blocks from LAST_BB_IN_PATH to VAR_BB. */
@@ -505,7 +505,9 @@ fsm_find_control_statement_thread_paths (tree name,
NEXT_PATH. Don't add them here to avoid pollution. */
for (unsigned int i = 0; i < next_path->length () - 1; i++)
{
- if (visited_bbs->contains ((*next_path)[i]))
+ if (visited_bbs->contains ((*next_path)[i])
+ || (bb_loop_depth (last_bb_in_path)
+ > bb_loop_depth ((*next_path)[i])))
{
vec_free (next_path);
return;
@@ -557,7 +559,12 @@ fsm_find_control_statement_thread_paths (tree name,
into the canonical form and register it. */
edge taken_edge = profitable_jump_thread_path (path, bbi, name, arg);
if (taken_edge)
- convert_and_register_jump_thread_path (path, taken_edge);
+ {
+ if (bb_loop_depth (taken_edge->src)
+ >= bb_loop_depth (taken_edge->dest))
+ convert_and_register_jump_thread_path (path, taken_edge);
+ path->pop ();
+ }
}
}
else if (gimple_code (def_stmt) == GIMPLE_ASSIGN)
@@ -578,7 +585,12 @@ fsm_find_control_statement_thread_paths (tree name,
edge taken_edge = profitable_jump_thread_path (path, var_bb,
name, arg);
if (taken_edge)
- convert_and_register_jump_thread_path (path, taken_edge);
+ {
+ if (bb_loop_depth (taken_edge->src)
+ >= bb_loop_depth (taken_edge->dest))
+ convert_and_register_jump_thread_path (path, taken_edge);
+ path->pop ();
+ }
/* And put the current block back onto the path so that the
state of the stack is unchanged when we leave. */
pr71403 (and its duplicates) show a problem where we thread a backedge from an outer loop to the header of an inner loop. This looks all find and good at the CFG level, but it essentially combines the inner and outer loop with parts of the loop executing on some iterations, but not on others. Worse yet, that will change the number of iterations of the loop, which wrecks havoc with the unroller. This patch avoids those jumps threads. It was also a good time to pull some path stack management out of a routine where it did not belong (convert_and_register_jump_thread_path). Bootstrapped and regression tested on x86_64 linux. Installing on the trunk. jeff commit 018f8824b168a5719defb8974efd110777b6b83b Author: law <law@138bc75d-0d04-0410-961f-82ee72b054a4> Date: Mon Jun 13 20:55:59 2016 +0000 PR tree-optimization/71403 * tree-ssa-threadbackward.c (convert_and_register_jump_thread_path): No longer accept reference to path. Do not pop items off the path anymore. (fsm_find_control_statement_thread_paths): Do not allow threading to a deeper loop nest. Pop the last item off the path here rather than in convert_and_register_jump_thread_path. PR tree-optimization/71403 * c-c++-common/ubsan/pr71403-1.c: New test. * c-c++-common/ubsan/pr71403-2.c: New test. * c-c++-common/ubsan/pr71403-3.c: New test. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@237403 138bc75d-0d04-0410-961f-82ee72b054a4