Fix ivec self-append. Closes #816

Author: brson

src/comp/middle/trans_ivec.rs

@@ -384,6 +384,12 @@ fn trans_append(cx: &@block_ctxt, t: ty::t, orig_lhs: ValueRef,
     rs = reserve_space(bcx, llunitty, lhs, rhs_len);
     let lhs_data = rs.val;
     bcx = rs.bcx;
+
+    // If rhs is lhs then our rhs pointer may have changed
+    rhs_len_and_data = get_len_and_data(bcx, rhs, unit_ty);
+    rhs_data = rhs_len_and_data.data;
+    bcx = rhs_len_and_data.bcx;
+
     // Work out the end pointer.
 
     let lhs_unscaled_idx = bcx.build.UDiv(rhs_len, llsize_of(llunitty));

src/test/run-pass/vec-self-append.rs

@@ -1,13 +1,40 @@
-// xfail-stage1
-// xfail-stage2
-// xfail-stage3
-
 use std;
 import std::vec;
 
-fn main() {
+fn test_heap_to_heap() {
+    // a spills onto the heap
+    let a = [0, 1, 2, 3, 4];
+    a += a;
+    assert vec::len(a) == 10u;
+    assert a[0] == 0;
+    assert a[1] == 1;
+    assert a[2] == 2;
+    assert a[3] == 3;
+    assert a[4] == 4;
+    assert a[5] == 0;
+    assert a[6] == 1;
+    assert a[7] == 2;
+    assert a[8] == 3;
+    assert a[9] == 4;
+}
+
+fn test_stack_to_heap() {
+    // a is entirely on the stack
+    let a = [0, 1, 2];
+    // a spills to the heap
+    a += a;
+    assert vec::len(a) == 6u;
+    assert a[0] == 0;
+    assert a[1] == 1;
+    assert a[2] == 2;
+    assert a[3] == 0;
+    assert a[4] == 1;
+    assert a[5] == 2;
+}
+
+fn test_loop() {
     // Make sure we properly handle repeated self-appends.
-    let a: [int] = ~[0];
+    let a: [int] = [0];
     let i = 20;
     let expected_len = 1u;
     while i > 0 {
@@ -18,3 +45,9 @@ fn main() {
         expected_len *= 2u;
     }
 }
+
+fn main() {
+    test_heap_to_heap();
+    test_stack_to_heap();
+    test_loop();
+}