tree-vrp.c (extract_range_from_binary_expr): If flag_non_call_exceptions don't eliminate division by zero.

gcc/:
	* tree-vrp.c (extract_range_from_binary_expr): If
	flag_non_call_exceptions don't eliminate division by zero.
	* simplify-rtx.c (simplify_binary_operation_1): Likewise.
gcc/testsuite/:
	* gcc.c-torture/execute/20101011-1.c: New test.
	* gcc.c-torture/execute/20101011-1.x: New test driver.

From-SVN: r165884

6 files changed, 76 insertions, 1 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 53b43f0..a2dee2e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-10-23  Ian Lance Taylor  <iant@google.com>
+
+	* tree-vrp.c (extract_range_from_binary_expr): If
+	flag_non_call_exceptions don't eliminate division by zero.
+	* simplify-rtx.c (simplify_binary_operation_1): Likewise.
+
 2010-10-23  Nathan Froyd  <froydnj@codesourcery.com>
 
 	* cppbuiltin.c (define_builtin_macros_for_type_sizes): Define
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index e45917f..84f3863 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -2755,7 +2755,8 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode,
       else
 	{
 	  /* 0/x is 0 (or x&0 if x has side-effects).  */
-	  if (trueop0 == CONST0_RTX (mode))
+	  if (trueop0 == CONST0_RTX (mode)
+	      && !cfun->can_throw_non_call_exceptions)
 	    {
 	      if (side_effects_p (op1))
 		return simplify_gen_binary (AND, mode, op1, trueop0);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d742fbf..3ab40ac 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-10-23  Ian Lance Taylor  <iant@google.com>
+
+	* gcc.c-torture/execute/20101011-1.c: New test.
+	* gcc.c-torture/execute/20101011-1.x: New test driver.
+
 2010-10-23  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/46122
diff --git a/gcc/testsuite/gcc.c-torture/execute/20101011-1.c b/gcc/testsuite/gcc.c-torture/execute/20101011-1.c
new file mode 100644
index 0000000..4c36ad3
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20101011-1.c
@@ -0,0 +1,45 @@
+/* With -fnon-call-exceptions 0 / 0 should not be eliminated.  The .x
+   file sets the option.  */
+
+#ifdef SIGNAL_SUPPRESS
+# define DO_TEST 0
+#elif defined (__powerpc__) || defined (__PPC__) || defined (__ppc__) || defined (__POWERPC__) || defined (__ppc)
+  /* On PPC division by zero does not trap.  */
+# define DO_TEST 0
+#elif defined (__SPU__)
+  /* On SPU division by zero does not trap.  */
+# define DO_TEST 0
+#else
+# define DO_TEST 1
+#endif
+
+#if DO_TEST
+
+#include <signal.h>
+
+void
+sigfpe (int signum __attribute__ ((unused)))
+{
+  exit (0);
+}
+
+#endif
+
+/* When optimizing, the compiler is smart enough to constant fold the
+   static unset variables i and j to produce 0 / 0, but it can't
+   eliminate the assignment to the global k.  */
+static int i;
+static int j;
+int k;
+
+int
+main ()
+{
+#ifdef DO_TEST
+  signal (SIGFPE, sigfpe);
+  k = i / j;
+  abort ();
+#else
+  exit (0);
+#endif
+}
diff --git a/gcc/testsuite/gcc.c-torture/execute/20101011-1.x b/gcc/testsuite/gcc.c-torture/execute/20101011-1.x
new file mode 100644
index 0000000..b5c080d
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20101011-1.x
@@ -0,0 +1,2 @@
+set additional_flags "-fnon-call-exceptions"
+return 0
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 8ab986e..2103e1b 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -2456,6 +2456,22 @@ extract_range_from_binary_expr (value_range_t *vr,
 	    }
 	}
 
+      /* For divisions, if flag_non_call_exceptions is true, we must
+	 not eliminate a division by zero.  */
+      if ((code == TRUNC_DIV_EXPR
+	   || code == FLOOR_DIV_EXPR
+	   || code == CEIL_DIV_EXPR
+	   || code == EXACT_DIV_EXPR
+	   || code == ROUND_DIV_EXPR)
+	  && cfun->can_throw_non_call_exceptions
+	  && (vr1.type != VR_RANGE
+	      || symbolic_range_p (&vr1)
+	      || range_includes_zero_p (&vr1)))
+	{
+	  set_value_range_to_varying (vr);
+	  return;
+	}
+
       /* For divisions, if op0 is VR_RANGE, we can deduce a range
 	 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
 	 include 0.  */