---

yaml
---
r: 79847
b: refs/heads/try
c: 71bebeb
h: refs/heads/master
i:
  79845: 4f8c193
  79843: 0d49e86
  79839: 1181895
v: v3

Author: thestinger

[refs]

@@ -2,7 +2,7 @@
 refs/heads/master: ba9fa89bfb4aae53db93e9ecac31807af96356fc
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
 refs/heads/snap-stage3: 54ae2800ffb30513f89ce13d27ac3c8d095d98ac
-refs/heads/try: 3f99540e9e1b32f042989ffde6d40f76477098c1
+refs/heads/try: 71bebebc37fbb229877da88dde13c2f35913bd77
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: 147ecfdd8221e4a4d4e090486829a06da1e0ca3c

branches/try/src/librustc/middle/trans/base.rs

@@ -244,6 +244,17 @@ pub fn decl_rust_fn(ccx: &mut CrateContext, inputs: &[ty::t], output: ty::t,
         }
     }
 
+    // The out pointer will never alias with any other pointers, as the object only exists at a
+    // language level after the call. It can also be tagged with SRet to indicate that it is
+    // guaranteed to point to a usable block of memory for the type.
+    if uses_outptr {
+        unsafe {
+            let outptr = llvm::LLVMGetParam(llfn, 0);
+            llvm::LLVMAddAttribute(outptr, lib::llvm::StructRetAttribute as c_uint);
+            llvm::LLVMAddAttribute(outptr, lib::llvm::NoAliasAttribute as c_uint);
+        }
+    }
+
     llfn
 }