[llvm] r242808 - [RewriteStatepointsForGC] Hoist some code out of a loop

[Philip Reames]

Author: reames
Date: Tue Jul 21 12:18:03 2015
New Revision: 242808

URL: http://llvm.org/viewvc/llvm-project?rev=242808&view=rev
Log:
[RewriteStatepointsForGC] Hoist some code out of a loop


Modified:
    llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp?rev=242808&r1=242807&r2=242808&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp Tue Jul 21 12:18:03 2015
@@ -1164,21 +1164,22 @@ static void CreateGCRelocates(ArrayRef<l
                               ArrayRef<llvm::Value *> BasePtrs,
                               Instruction *StatepointToken,
                               IRBuilder<> Builder) {
+  if (LiveVariables.empty())
+    return;
+  
+  // All gc_relocate are set to i8 addrspace(1)* type. We originally generated
+  // unique declarations for each pointer type, but this proved problematic
+  // because the intrinsic mangling code is incomplete and fragile.  Since
+  // we're moving towards a single unified pointer type anyways, we can just
+  // cast everything to an i8* of the right address space.  A bitcast is added
+  // later to convert gc_relocate to the actual value's type. 
   Module *M = StatepointToken->getModule();
+  auto AS = cast<PointerType>(LiveVariables[0]->getType())->getAddressSpace();
+  Type *Types[] = {Type::getInt8PtrTy(M->getContext(), AS)};
+  Value *GCRelocateDecl =
+    Intrinsic::getDeclaration(M, Intrinsic::experimental_gc_relocate, Types);
 
   for (unsigned i = 0; i < LiveVariables.size(); i++) {
-    // We generate a (potentially) unique declaration for every pointer type
-    // combination.  This results is some blow up the function declarations in
-    // the IR, but removes the need for argument bitcasts which shrinks the IR
-    // greatly and makes it much more readable.
-    SmallVector<Type *, 1> Types;                 // one per 'any' type
-    // All gc_relocate are set to i8 addrspace(1)* type. This could help avoid
-    // cases where the actual value's type mangling is not supported by llvm. A
-    // bitcast is added later to convert gc_relocate to the actual value's type.
-    Types.push_back(Type::getInt8PtrTy(M->getContext(), 1));
-    Value *GCRelocateDecl = Intrinsic::getDeclaration(
-        M, Intrinsic::experimental_gc_relocate, Types);
-
     // Generate the gc.relocate call and save the result
     Value *BaseIdx =
       Builder.getInt32(LiveStart + find_index(LiveVariables, BasePtrs[i]));