[llvm] r216846 - Consider addrspaces in canLosslesslyBitCastTo()

[Matt Arsenault]

Author: arsenm
Date: Sun Aug 31 14:19:57 2014
New Revision: 216846

URL: http://llvm.org/viewvc/llvm-project?rev=216846&view=rev
Log:
Consider addrspaces in canLosslesslyBitCastTo()

Make this conservatively correct and report false for different
address spaces, which might require a nontrivial translation.

Based on the few uses of this, I don't think this currently
breaks anything.

Modified:
    llvm/trunk/lib/IR/Type.cpp

Modified: llvm/trunk/lib/IR/Type.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Type.cpp?rev=216846&r1=216845&r2=216846&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Type.cpp (original)
+++ llvm/trunk/lib/IR/Type.cpp Sun Aug 31 14:19:57 2014
@@ -89,9 +89,13 @@ bool Type::canLosslesslyBitCastTo(Type *
 
   // At this point we have only various mismatches of the first class types
   // remaining and ptr->ptr. Just select the lossless conversions. Everything
-  // else is not lossless.
-  if (this->isPointerTy())
-    return Ty->isPointerTy();
+  // else is not lossless. Conservatively assume we can't losslessly convert
+  // between pointers with different address spaces.
+  if (const PointerType *PTy = dyn_cast<PointerType>(this)) {
+    if (const PointerType *OtherPTy = dyn_cast<PointerType>(Ty))
+      return PTy->getAddressSpace() == OtherPTy->getAddressSpace();
+    return false;
+  }
   return false;  // Other types have no identity values
 }