Optimize away unnecessary address casts.

Removes unnecessary casts from non-generic address spaces to the generic address
space for certain code patterns.

Patch by Jingyue Wu.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205571 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/lib/Target/NVPTX/NVPTXTargetMachine.cpp b/lib/Target/NVPTX/NVPTXTargetMachine.cpp
index 7d7d79314c..9aa7dbb4fa 100644
--- a/lib/Target/NVPTX/NVPTXTargetMachine.cpp
+++ b/lib/Target/NVPTX/NVPTXTargetMachine.cpp
@@ -50,6 +50,7 @@ namespace llvm {
 void initializeNVVMReflectPass(PassRegistry&);
 void initializeGenericToNVVMPass(PassRegistry&);
 void initializeNVPTXAssignValidGlobalNamesPass(PassRegistry&);
+void initializeNVPTXFavorNonGenericAddrSpacesPass(PassRegistry &);
 }
 
 extern "C" void LLVMInitializeNVPTXTarget() {
@@ -62,6 +63,8 @@ extern "C" void LLVMInitializeNVPTXTarget() {
   initializeNVVMReflectPass(*PassRegistry::getPassRegistry());
   initializeGenericToNVVMPass(*PassRegistry::getPassRegistry());
   initializeNVPTXAssignValidGlobalNamesPass(*PassRegistry::getPassRegistry());
+  initializeNVPTXFavorNonGenericAddrSpacesPass(
+    *PassRegistry::getPassRegistry());
 }
 
 static std::string computeDataLayout(const NVPTXSubtarget &ST) {
@@ -143,6 +146,12 @@ void NVPTXPassConfig::addIRPasses() {
   TargetPassConfig::addIRPasses();
   addPass(createNVPTXAssignValidGlobalNamesPass());
   addPass(createGenericToNVVMPass());
+  addPass(createNVPTXFavorNonGenericAddrSpacesPass());
+  // The FavorNonGenericAddrSpaces pass may remove instructions and leave some
+  // values unused. Therefore, we run a DCE pass right afterwards. We could
+  // remove unused values in an ad-hoc manner, but it requires manual work and
+  // might be error-prone.
+  addPass(createDeadCodeEliminationPass());
 }
 
 bool NVPTXPassConfig::addInstSelector() {