From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 7 Jul 2016 21:49:58 +0000 (+0200)
Subject: backport: re PR rtl-optimization/70222 (Test miscompiled with -O1)
X-Git-Tag: releases/gcc-4.9.4~90
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c529f41e4577999c05889ca5279d16c366ef0d7;p=thirdparty%2Fgcc.git

backport: re PR rtl-optimization/70222 (Test miscompiled with -O1)

	Backported from mainline
	2016-03-15  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/70222
	* combine.c (simplify_shift_const_1): For A >> B >> C LSHIFTRT
	optimization if mode is different from result_mode, queue up masking
	of the result in outer_op.  Formatting fix.

	* gcc.c-torture/execute/pr70222-1.c: New test.
	* gcc.c-torture/execute/pr70222-2.c: New test.

From-SVN: r238140
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1abaf860f55b..52b69c8f3ea2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,13 @@
 2016-07-07  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-03-15  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/70222
+	* combine.c (simplify_shift_const_1): For A >> B >> C LSHIFTRT
+	optimization if mode is different from result_mode, queue up masking
+	of the result in outer_op.  Formatting fix.
+
 	2016-03-11  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/70169
diff --git a/gcc/combine.c b/gcc/combine.c
index a22aba7d48e4..c48d9b11e47b 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -10173,9 +10173,19 @@ simplify_shift_const_1 (enum rtx_code code, enum machine_mode result_mode,
 		   && CONST_INT_P (XEXP (varop, 0))
 		   && !CONST_INT_P (XEXP (varop, 1)))
 	    {
+	      /* For ((unsigned) (cstULL >> count)) >> cst2 we have to make
+		 sure the result will be masked.  See PR70222.  */
+	      if (code == LSHIFTRT
+		  && mode != result_mode
+		  && !merge_outer_ops (&outer_op, &outer_const, AND,
+				       GET_MODE_MASK (result_mode)
+				       >> orig_count, result_mode,
+				       &complement_p))
+		break;
+
 	      rtx new_rtx = simplify_const_binary_operation (code, mode,
-							 XEXP (varop, 0),
-							 GEN_INT (count));
+							     XEXP (varop, 0),
+							     GEN_INT (count));
 	      varop = gen_rtx_fmt_ee (code, mode, new_rtx, XEXP (varop, 1));
 	      count = 0;
 	      continue;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9a70102ba3e4..dac1b34b1b3b 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,12 @@
 2016-07-07  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2016-03-15  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/70222
+	* gcc.c-torture/execute/pr70222-1.c: New test.
+	* gcc.c-torture/execute/pr70222-2.c: New test.
+
 	2016-03-11  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/70169
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr70222-1.c b/gcc/testsuite/gcc.c-torture/execute/pr70222-1.c
new file mode 100644
index 000000000000..d79672e7fb4c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr70222-1.c
@@ -0,0 +1,30 @@
+/* PR rtl-optimization/70222 */
+
+int a = 1;
+unsigned int b = 2;
+int c = 0;
+int d = 0;
+
+void
+foo ()
+{
+  int e = ((-(c >= c)) < b) > ((int) (-1ULL >> ((a / a) * 15)));
+  d = -e;
+}
+
+__attribute__((noinline, noclone)) void
+bar (int x)
+{
+  if (x != -1)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+#if __CHAR_BIT__ == 8 && __SIZEOF_INT__ == 4 && __SIZEOF_LONG_LONG__ == 8
+  foo ();
+  bar (d);
+#endif
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr70222-2.c b/gcc/testsuite/gcc.c-torture/execute/pr70222-2.c
new file mode 100644
index 000000000000..7611c986a9b7
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr70222-2.c
@@ -0,0 +1,20 @@
+/* PR rtl-optimization/70222 */
+
+#if __CHAR_BIT__ == 8 && __SIZEOF_INT__ == 4 && __SIZEOF_LONG_LONG__ == 8
+__attribute__((noinline, noclone)) unsigned int
+foo (int x)
+{
+  unsigned long long y = -1ULL >> x;
+  return (unsigned int) y >> 31;
+}
+#endif
+
+int
+main ()
+{
+#if __CHAR_BIT__ == 8 && __SIZEOF_INT__ == 4 && __SIZEOF_LONG_LONG__ == 8
+  if (foo (15) != 1 || foo (32) != 1 || foo (33) != 0)
+    __builtin_abort ();
+#endif
+  return 0;
+}