simplify-rtx.c (simplify_subreg): Do not over-extend vector constants.

2003-06-16  Aldy Hernandez  <aldyh@redhat.com>

	* simplify-rtx.c (simplify_subreg): Do not over-extend vector
	constants.

	* testsuite/gcc.c-torture/execute/simd-4.c: New.

[[Split portion of a mixed commit.]]

From-SVN: r68047.2

gcc/simplify-rtx.c

@@ -2657,6 +2657,10 @@ simplify_subreg (outermode, op, innermode, byte)
 	  unsigned i = BYTES_BIG_ENDIAN ? offset : offset + n_elts - 1;
 	  unsigned step = BYTES_BIG_ENDIAN ? 1 : -1;
 	  int shift = BITS_PER_UNIT * elt_size;
+	  unsigned HOST_WIDE_INT unit_mask;
+
+	  unit_mask = (unsigned HOST_WIDE_INT) -1
+	    >> (sizeof (HOST_WIDE_INT) * BITS_PER_UNIT - shift);
 
 	  for (; n_elts--; i += step)
 	    {
@@ -2675,7 +2679,7 @@ simplify_subreg (outermode, op, innermode, byte)
 	      if (high >> (HOST_BITS_PER_WIDE_INT - shift))
 		return NULL_RTX;
 	      high = high << shift | sum >> (HOST_BITS_PER_WIDE_INT - shift);
-	      sum = (sum << shift) + INTVAL (elt);
+	      sum = (sum << shift) + (INTVAL (elt) & unit_mask);
 	    }
 	  if (GET_MODE_BITSIZE (outermode) <= HOST_BITS_PER_WIDE_INT)
 	    return GEN_INT (trunc_int_for_mode (sum, outermode));

gcc/testsuite/gcc.c-torture/execute/simd-4.c

+typedef int __attribute__((vector_size(8))) v2si;
+long long s64;
+
+static inline long long
+__ev_convert_s64 (v2si a)
+{
+  return (long long) a;
+}
+
+int main()
+{
+  s64 = __ev_convert_s64 ((v2si){1,0xffffffff});
+  if (s64 != 0x1ffffffffLL)
+    abort ();
+  return 0;
+}