re PR c/5681 (gcc 3.0.3 produces wrong assembler code)

	PR c/5681:
	* expr.c (safe_from_p): Pass VOIDmode to true_dependence instead of
	GET_MODE (x).

	* gcc.c-torture/execute/20020213-1.c: New test.

From-SVN: r49746

gcc/ChangeLog

 2002-02-13  Jakub Jelinek  <jakub@redhat.com>
 
+	PR c/5681:
+	* expr.c (safe_from_p): Pass VOIDmode to true_dependence instead of
+	GET_MODE (x).
+
+2002-02-13  Jakub Jelinek  <jakub@redhat.com>
+
 	PR optimization/5547:
 	* config/i386/i386.c (i386_simplify_dwarf_addr): Simplify
 	all valid IA-32 address modes involving non-scaled %ebx and

gcc/expr.c

@@ -5728,7 +5728,7 @@ safe_from_p (x, exp, top_p)
 	 are memory and they conflict.  */
       return ! (rtx_equal_p (x, exp_rtl)
 		|| (GET_CODE (x) == MEM && GET_CODE (exp_rtl) == MEM
-		    && true_dependence (exp_rtl, GET_MODE (x), x,
+		    && true_dependence (exp_rtl, VOIDmode, x,
 					rtx_addr_varies_p)));
     }
 

gcc/testsuite/ChangeLog

@@ -2,6 +2,8 @@
 
 	* g++.dg/other/debug3.C: New test.
 
+	* gcc.c-torture/execute/20020213-1.c: New test.
+
 2002-02-13  Richard Smith <richard@ex-parrot.com>
 
 	* g++.old-deja/g++.other/thunk1.C: New test.

gcc/testsuite/gcc.c-torture/execute/20020213-1.c

+/* PR c/5681
+   This testcase failed on IA-32 at -O0, because safe_from_p
+   incorrectly assumed it is safe to first write into a.a2 b-1
+   and then read the original value from it.  */
+
+int bar (float);
+
+struct A {
+  float a1;
+  int a2;
+} a;
+
+int b;
+
+void foo (void)
+{
+  a.a2 = bar (a.a1);
+  a.a2 = a.a2 < b - 1 ? a.a2 : b - 1;
+  if (a.a2 >= b - 1)
+    abort ();
+}
+
+int bar (float x)
+{
+  return 2241;
+}
+
+int main()
+{
+  a.a1 = 1.0f;
+  b = 3384;
+  foo ();
+  return 0;
+}