From: Bin Cheng <bin.cheng@arm.com>
Date: Tue, 1 Aug 2017 09:17:29 +0000 (+0000)
Subject: re PR tree-optimization/81620 (ICE in is_inv_store_elimination_chain, at tree-predcom... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=39637a44f4d65ccb23f83399eefd5f06d4bf4e4a;p=gcc.git

re PR tree-optimization/81620 (ICE in is_inv_store_elimination_chain, at tree-predcom.c:1651 with -O3)

	PR tree-optimization/81620
	* tree-predcom.c (add_ref_to_chain): Don't set has_max_use_after
	for store-store chain.

	gcc/testsuite
	* gcc.dg/tree-ssa/pr81620-1.c: New.
	* gcc.dg/tree-ssa/pr81620-2.c: New.

From-SVN: r250763
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ee6fcd5794e..c8ed19d41ad 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+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.
+
 2017-08-01  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/81588
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 08d649c8ed6..e2f695fa001 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+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.
+
 2017-08-01  Dominique d'Humieres  <dominiq@lps.ens.fr>
 
 	PR testsuite/53542
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr81620-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr81620-1.c
new file mode 100644
index 00000000000..f8f2dd8ad6c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr81620-1.c
@@ -0,0 +1,20 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fno-tree-loop-vectorize -fdump-tree-pcom-details" } */
+
+int a[7];
+char b;
+void abort (void);
+
+int main() {
+  b = 4;
+  for (; b; b--) {
+    a[b] = b;
+    a[b + 2] = 1;
+  }
+  if (a[0] != 0 || a[1] != 1 || a[2] != 2
+      || a[3] != 1 || a[4] != 1 || a[5] != 1 || a[6] != 1)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "Store-stores chain" 1 "pcom" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr81620-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr81620-2.c
new file mode 100644
index 00000000000..85a8e350840
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr81620-2.c
@@ -0,0 +1,25 @@
+/* { dg-do run } */
+/* { dg-options "-O3 -fno-tree-loop-vectorize -fdump-tree-pcom-details" } */
+
+int a[200];
+char b;
+void abort (void);
+
+int main() {
+  int i;
+  b = 100;
+  for (; b; b--) {
+    a[b] = 2;
+    a[b + 2] = 1;
+  }
+
+  if (a[0] != 0 || a[1] != 2 || a[2] != 2)
+    abort ();
+  for (i = 3; i < 103; i++)
+    if (a[i] != 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 a4011bf4698..f7a57a43a0e 100644
--- a/gcc/tree-predcom.c
+++ b/gcc/tree-predcom.c
@@ -1069,7 +1069,9 @@ add_ref_to_chain (chain_p chain, dref ref)
       chain->has_max_use_after = false;
     }
 
-  if (ref->distance == chain->length
+  /* Don't set the flag for store-store chain since there is no use.  */
+  if (chain->type != CT_STORE_STORE
+      && ref->distance == chain->length
       && ref->pos > root->pos)
     chain->has_max_use_after = true;