Remove AddrSpaceCast on function from llvm.global.annotations (#1337)

lib/AnnotationToMetadataPass.cpp

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/Operator.h"
 
 #include "AnnotationToMetadataPass.h"
 #include "Constants.h"
@@ -30,6 +31,7 @@ clspv::AnnotationToMetadataPass::run(Module &M, ModuleAnalysisManager &) {
 
       // list of processed strings to delete at the end
       SmallPtrSet<GlobalValue *, 4> to_erase;
+      SmallPtrSet<Constant *, 4> addrspacecast_to_erase;
 
       ConstantArray *annotations_array =
           dyn_cast<ConstantArray>(GV.getOperand(0));
@@ -38,6 +40,11 @@ clspv::AnnotationToMetadataPass::run(Module &M, ModuleAnalysisManager &) {
             dyn_cast<ConstantStruct>(annotation_entry.get());
 
         auto op0 = annotation_struct->getOperand(0);
+        if (isa<AddrSpaceCastOperator>(op0)) {
+          // We need to make sure to erase those to avoid keeping a reference on
+          // functions preventing them from being removed
+          addrspacecast_to_erase.insert(op0);
+        }
         Function *entry_point = dyn_cast<Function>(op0->stripPointerCasts());
 
         auto op1 = annotation_struct->getOperand(1);
@@ -66,6 +73,9 @@ clspv::AnnotationToMetadataPass::run(Module &M, ModuleAnalysisManager &) {
       for (auto gv : to_erase) {
         gv->eraseFromParent();
       }
+      for (auto as : addrspacecast_to_erase) {
+        as->destroyConstant();
+      }
       break;
     }
   }

lib/LongVectorLoweringPass.cpp

@@ -1961,11 +1961,8 @@ void clspv::LongVectorLoweringPass::cleanDeadFunctions() {
     Progress = (DeadFunctions.size() < PreviousSize);
   }
 
-  // TODO: uncomment assert.
-  // LLVM now creates some addrspacecast on function that are never used in any
-  // function. It prevents supposedly-dead functions from being removed
-  // assert(DeadFunctions.empty() &&
-  //        "Not all supposedly-dead functions were removed!");
+  assert(DeadFunctions.empty() &&
+         "Not all supposedly-dead functions were removed!");
 }
 
 void clspv::LongVectorLoweringPass::cleanDeadGlobals() {

lib/UndoByvalPass.cpp

@@ -126,10 +126,7 @@ PreservedAnalyses clspv::UndoByvalPass::run(Module &M,
       // Update caller site.
       for (auto User : Users) {
         // Create new call instruction for new function without byval.
-        CallInst *Call = dyn_cast<CallInst>(User);
-        if (Call == nullptr) {
-          continue;
-        }
+        CallInst *Call = cast<CallInst>(User);
         auto Callee = Call->getCalledFunction();
 
         SmallVector<Value *, 8> Args;

test/InlineFuncWithSingleCallSite/two_kernels_partial_chain_inline.cl

@@ -17,7 +17,9 @@
 // CHECK-NOT: OpFunctionCall
 // CHECK: OpFunctionEnd
 
+__attribute__((noinline))
 int func_3(local int *in, int n) { return in[n]; }
+__attribute__((noinline))
 int func_2(local int *in, int n) { return func_3(in, n); }
 __attribute__((noinline))
 int func_1(local int *in, int n) { return func_2(in, n); }