[PATCH] Address Space Casting

[Michele Scandale]

================
Comment at: lib/IR/AutoUpgrade.cpp:404
@@ +403,2 @@
+  return Opc;
+}
----------------
Eli Friedman wrote:
> This isn't appropriate: this transformation changes the semantics of the code.  bitcast is explicitly not equivalent to addrspacecast; it's equivalent to a ptrtoint+inttoptr pair.
>From what have been discussed before (http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-August/064674.html) seems that before bitcast was used to convert two pointers between different address spaces... That's the reason for that code....

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Comment at: docs/LangRef.rst:5708
@@ +5707,3 @@
+      %X = bitcast i32* %x to addrspace(1) i32*    ; yields addrspace(1) i32*:%x
+      %Y = bitcast addrspace(1) <2 x i32>* %y to addrspace(2) i64*    ; yields addrspace(2) i32*:%y
+
----------------
Eli Friedman wrote:
> Might want to double-check this. :)
Argh.... I forgot to change the operation


http://llvm-reviews.chandlerc.com/D1401