[PATCH] D18616: [NVPTX] Move NVVMReflect pass out of codegen passes.

[Justin Lebar via llvm-commits]

jlebar created this revision.
jlebar added a reviewer: rnk.
jlebar added subscribers: llvm-commits, tra.
Herald added a subscriber: jholewinski.

Currently the NVVMReflect pass is run at the beginning of our backend
passes.  But really, it should be run as early as possible, as it's
simply resolving an "if" statement in code.  So move it into
TargetMachine::addEarlyAsPossiblePasses.

(Specifically, NVVMReflect changes each call to the __nvvm_reflect
function or llvm.nvvm.reflect intrinsic into an integer constant, based
on the pass's configuration.  Clearly we miss many optimization
opportunities if we perform this transformation at the beginning of
codegen.)

http://reviews.llvm.org/D18616

Files:
  lib/Target/NVPTX/NVPTXTargetMachine.cpp
  lib/Target/NVPTX/NVPTXTargetMachine.h

Index: lib/Target/NVPTX/NVPTXTargetMachine.h
===================================================================
--- lib/Target/NVPTX/NVPTXTargetMachine.h
+++ lib/Target/NVPTX/NVPTXTargetMachine.h
@@ -61,6 +61,7 @@
     return TLOF.get();
   }
 
+  void addEarlyAsPossiblePasses(PassManagerBase &PM) override;
   TargetIRAnalysis getTargetIRAnalysis() override;
 
 }; // NVPTXTargetMachine.
Index: lib/Target/NVPTX/NVPTXTargetMachine.cpp
===================================================================
--- lib/Target/NVPTX/NVPTXTargetMachine.cpp
+++ lib/Target/NVPTX/NVPTXTargetMachine.cpp
@@ -167,6 +167,10 @@
   return new NVPTXPassConfig(this, PM);
 }
 
+void NVPTXTargetMachine::addEarlyAsPossiblePasses(PassManagerBase &PM) {
+  PM.add(createNVVMReflectPass());
+}
+
 TargetIRAnalysis NVPTXTargetMachine::getTargetIRAnalysis() {
   return TargetIRAnalysis([this](const Function &F) {
     return TargetTransformInfo(NVPTXTTIImpl(this, F));
@@ -228,7 +232,6 @@
   disablePass(&PostRASchedulerID);
   disablePass(&FuncletLayoutID);
 
-  addPass(createNVVMReflectPass());
   if (getOptLevel() != CodeGenOpt::None)
     addPass(createNVPTXImageOptimizerPass());
   addPass(createNVPTXAssignValidGlobalNamesPass());


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