[GPGPU] Support PHI nodes used in GPU kernel

Ensure the right scalar allocations are used as the host location of data
transfers. For the device code, we clear the allocation cache before device
code generation to be able to generate new device-specific allocation and
we need to make sure to add back the old host allocations as soon as the
device code generation is finished.

llvm-svn: 278126

1 files changed, 14 insertions, 10 deletions

diff --git a/polly/lib/CodeGen/PPCGCodeGeneration.cpp b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
index 32858fc213d..2ca25ab1238 100644
--- a/polly/lib/CodeGen/PPCGCodeGeneration.cpp
+++ b/polly/lib/CodeGen/PPCGCodeGeneration.cpp
@@ -722,14 +722,14 @@ void GPUNodeBuilder::createDataTransfer(__isl_take isl_ast_node *TransferStmt,
   auto ScopArray = (ScopArrayInfo *)(Array->user);
 
   Value *Size = getArraySize(Array);
-  Value *HostPtr = ScopArray->getBasePtr();
-
   Value *DevPtr = DeviceAllocations[ScopArray];
 
-  if (gpu_array_is_scalar(Array)) {
-    HostPtr = Builder.CreateAlloca(ScopArray->getElementType());
-    Builder.CreateStore(ScopArray->getBasePtr(), HostPtr);
-  }
+  Value *HostPtr;
+
+  if (gpu_array_is_scalar(Array))
+    HostPtr = BlockGen.getOrCreateAlloca(ScopArray);
+  else
+    HostPtr = ScopArray->getBasePtr();
 
   HostPtr = Builder.CreatePointerCast(HostPtr, Builder.getInt8PtrTy());
 
@@ -1074,6 +1074,10 @@ void GPUNodeBuilder::createKernel(__isl_take isl_ast_node *KernelStmt) {
   Instruction &HostInsertPoint = *Builder.GetInsertPoint();
   IslExprBuilder::IDToValueTy HostIDs = IDToValue;
   ValueMapT HostValueMap = ValueMap;
+  BlockGenerator::ScalarAllocaMapTy HostScalarMap = ScalarMap;
+  BlockGenerator::ScalarAllocaMapTy HostPHIOpMap = PHIOpMap;
+  ScalarMap.clear();
+  PHIOpMap.clear();
 
   SetVector<const Loop *> Loops;
 
@@ -1102,9 +1106,9 @@ void GPUNodeBuilder::createKernel(__isl_take isl_ast_node *KernelStmt) {
   Builder.SetInsertPoint(&HostInsertPoint);
   IDToValue = HostIDs;
 
-  ValueMap = HostValueMap;
-  ScalarMap.clear();
-  PHIOpMap.clear();
+  ValueMap = std::move(HostValueMap);
+  ScalarMap = std::move(HostScalarMap);
+  PHIOpMap = std::move(HostPHIOpMap);
   EscapeMap.clear();
   IDToSAI.clear();
   Annotator.resetAlternativeAliasBases();
@@ -1283,7 +1287,7 @@ void GPUNodeBuilder::prepareKernelArguments(ppcg_kernel *Kernel, Function *FN) {
       continue;
     }
 
-    Value *Alloca = BlockGen.getOrCreateScalarAlloca(SAI->getBasePtr());
+    Value *Alloca = BlockGen.getOrCreateAlloca(SAI);
     Value *ArgPtr = &*Arg;
     Type *TypePtr = SAI->getElementType()->getPointerTo();
     Value *TypedArgPtr = Builder.CreatePointerCast(ArgPtr, TypePtr);