simplify-rtx.c (simplify_binary_operation): If gen_lowpart_common fails, use gen_lowpart_SUBREG.

	* simplify-rtx.c (simplify_binary_operation) [DIV]: If
	gen_lowpart_common fails, use gen_lowpart_SUBREG.

	* gcc.c-torture/compile/20020103-1.c: New test.

From-SVN: r48514

gcc/ChangeLog

+2002-01-03  Jakub Jelinek  <jakub@redhat.com>
+
+	* simplify-rtx.c (simplify_binary_operation) [DIV]: If
+	gen_lowpart_common fails, use gen_lowpart_SUBREG.
+
 2002-01-03  Turly O'Connor  <turly@apple.com>
+
 	* darwin.c (machopic_output_possible_stub_label): Don't generate
 	stub routines for pseudo-stubs which we've just defined.
 

gcc/simplify-rtx.c

@@ -1413,8 +1413,15 @@ simplify_binary_operation (code, mode, op0, op1)
 	case DIV:
 	  if (trueop1 == CONST1_RTX (mode))
 	    {
+	      /* On some platforms DIV uses narrower mode than its
+		 operands.  */
 	      rtx x = gen_lowpart_common (mode, op0);
-	      return x ? x : op0;
+	      if (x)
+		return x;
+	      else if (mode != GET_MODE (op0) && GET_MODE (op0) != VOIDmode)
+		return gen_lowpart_SUBREG (mode, op0);
+	      else
+		return op0;
 	    }
 
 	  /* In IEEE floating point, 0/x is not always 0.  */

gcc/testsuite/ChangeLog

@@ -2,6 +2,8 @@
 
 	* g++.dg/other/debug2.C: New test.
 
+	* gcc.c-torture/compile/20020103-1.c: New test.
+
 2002-01-02  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.dg/gnu89-init-1.c: Added new tests.

gcc/testsuite/gcc.c-torture/compile/20020103-1.c

+/* This testcase failed on Alpha at -O2 when simplifying conditional
+   expressions.  */
+
+int foo (void);
+
+struct A
+{
+  int a, b, c, d;
+};
+
+void bar (struct A *x)
+{
+  int e, f;
+
+  e = foo ();
+  e = e / x->b;
+  if (e < 1)
+    e = 1;
+  f = (x->a + x->c) / e;
+  if (f < x->d)
+    x->d -= (1 << 16) / 8;
+}