re PR tree-optimization/81627 (ICE on valid code at -O3: in check_loop_closed_ssa_use...

	PR tree-optimization/81627
	* tree-predcom.c (prepare_finalizers): Always rewrite into loop
	closed ssa form for store-store chain.

	gcc/testsuite
	* gcc.dg/tree-ssa/pr81627.c: New.

From-SVN: r250764

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c8ed19d..9e09d56 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2017-08-01  Bin Cheng  <bin.cheng@arm.com>
 
+       PR tree-optimization/81627
+       * tree-predcom.c (prepare_finalizers): Always rewrite into loop
+       closed ssa form for store-store chain.
+
+2017-08-01  Bin Cheng  <bin.cheng@arm.com>
+
        PR tree-optimization/81620
        * tree-predcom.c (add_ref_to_chain): Don't set has_max_use_after
        for store-store chain.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e2f695f..a86b281 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2017-08-01  Bin Cheng  <bin.cheng@arm.com>
 
+       PR tree-optimization/81627
+       * gcc.dg/tree-ssa/pr81627.c: New.
+
+2017-08-01  Bin Cheng  <bin.cheng@arm.com>
+
        PR tree-optimization/81620
        * gcc.dg/tree-ssa/pr81620-1.c: New.
        * gcc.dg/tree-ssa/pr81620-2.c: New.

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr81627.c b/gcc/testsuite/gcc.dg/tree-ssa/pr81627.c
new file mode 100644 (file)
index 0000000..9ba43be
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr81627.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fno-tree-loop-vectorize -fdump-tree-pcom-details" } */
+
+int a, b, c, d[6], e = 3, f;
+
+void abort (void);
+void fn1 ()
+{
+  for (b = 1; b < 5; b++)
+    {
+      for (c = 0; c < 5; c++)
+        d[b] = e;
+      if (a)
+        f++;
+      d[b + 1] = 1;
+    }
+}
+
+int main ()
+{
+  fn1 ();
+  if (d[0] != 0 || d[1] != 3 || d[2] != 3
+      || d[3] != 3 || d[4] != 3 || d[5] != 1)
+    abort ();
+
+  return 0;
+}
+/* { dg-final { scan-tree-dump-times "Store-stores chain" 1 "pcom" } } */

diff --git a/gcc/tree-predcom.c b/gcc/tree-predcom.c
index f7a57a4..4538773 100644 (file)
--- a/gcc/tree-predcom.c
+++ b/gcc/tree-predcom.c
@@ -2983,11 +2983,11 @@ prepare_finalizers (struct loop *loop, vec<chain_p> chains)
       if (prepare_finalizers_chain (loop, chain))
        {
          i++;
-         /* We don't corrupt loop closed ssa form for store elimination
-            chain if eliminated stores only store loop invariant values
-            into memory.  */
-         if (!chain->inv_store_elimination)
-           loop_closed_ssa |= (!chain->inv_store_elimination);
+         /* Be conservative, assume loop closed ssa form is corrupted
+            by store-store chain.  Though it's not always the case if
+            eliminated stores only store loop invariant values into
+            memory.  */
+         loop_closed_ssa = true;
        }
       else
        {