PR rtl-optimization/89753

	* loop-unroll.c (decide_unroll_constant_iterations): Make guard for
	explicit unrolling factor even more robust.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@269791 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 568435819d7b26879e14ffe98e55dbcc91b33c4e..5ef58714b3e59e65a7989c751245a56f7c316fb9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-03-19  Eric Botcazou  <ebotcazou@adacore.com>
+
+       PR rtl-optimization/89753
+       * loop-unroll.c (decide_unroll_constant_iterations): Make guard for
+       explicit unrolling factor even more robust.
+
 2019-03-19  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/89726

diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c
index 0164762bee96e986b3828f5be0813f45f4406c8d..bc7840e4bfabb0af3564c49a48601aea4e2255ad 100644 (file)
--- a/gcc/loop-unroll.c
+++ b/gcc/loop-unroll.c
@@ -400,7 +400,7 @@ decide_unroll_constant_iterations (struct loop *loop, int flags)
     {
       /* However we cannot unroll completely at the RTL level a loop with
         constant number of iterations; it should have been peeled instead.  */
-      if ((unsigned) loop->unroll > desc->niter - 1)
+      if (desc->niter == 0 || (unsigned) loop->unroll > desc->niter - 1)
        {
          if (dump_file)
            fprintf (dump_file, ";; Loop should have been peeled\n");

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ae077a1fc8e74bbdfa486709a244a941dc71d533..4e35805af654f420b9418bc7f65b0fa355d511bc 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2019-03-19  Eric Botcazou  <ebotcazou@adacore.com>
+
+       * c-c++-common/unroll-7.c: New test.
+
 2019-03-19  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/89726

diff --git a/gcc/testsuite/c-c++-common/unroll-7.c b/gcc/testsuite/c-c++-common/unroll-7.c
new file mode 100644 (file)
index 0000000..8332e9f
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/unroll-7.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O -fno-tree-dominator-opts" } */
+
+int nv;
+
+void test (void)
+{
+  #pragma GCC unroll 2
+  for (nv = 0; nv < 1; ++nv)
+    {}
+}