[SYCL] Enable standard optimization pipeline for SYCL device compiler (#2049)

Author: bader

clang/lib/CodeGen/BackendUtil.cpp

@@ -42,7 +42,6 @@
 #include "llvm/Passes/StandardInstrumentations.h"
 #include "llvm/Support/BuryPointer.h"
 #include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Debug.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/TargetRegistry.h"
@@ -82,11 +81,6 @@
 #include "llvm/Transforms/Utils/SymbolRewriter.h"
 #include "llvm/Transforms/Utils/UniqueInternalLinkageNames.h"
 #include <memory>
-
-namespace SPIRV {
-  extern llvm::cl::opt<bool> SPIRVNoDerefAttr;
-}
-
 using namespace clang;
 using namespace llvm;
 
@@ -622,54 +616,22 @@ void EmitAssemblyHelper::CreatePasses(legacy::PassManager &MPM,
          CodeGenOpts.PrepareForThinLTO));
   }
 
-  // FIXME: This code is a workaround for a number of problems with optimized
-  // SYCL code for the SPIR target. This change trying to balance between doing
-  // too few and too many optimizations. The current approach is to disable as
-  // much as possible just to keep the compiler functional. Eventually we can
-  // consider allowing -On option to configure the optimization set for the FE
-  // device compiler as well, but before that we must fix all the functional and
-  // performance issues caused by LLVM transformantions.
-  // E.g. LLVM optimizations make use of llvm intrinsics, instructions, data
-  // types, etc., which are not supported by the SPIR-V translator (current
-  // "back-end" for SYCL device compiler).
-  // NOTE: We use "normal" inliner (i.e. from O2/O3), but limit the rest of
-  // optimization pipeline. Inliner is a must for enabling size reduction
-  // optimizations.
-  if (LangOpts.SYCLIsDevice && TargetTriple.isSPIR()) {
-    PMBuilder.OptLevel = 1;
-    PMBuilder.SizeLevel = 2;
-    PMBuilder.SLPVectorize = false;
-    PMBuilder.LoopVectorize = false;
-    PMBuilder.DivergentTarget = true;
-    PMBuilder.DisableGVNLoadPRE = true;
-    PMBuilder.ForgetAllSCEVInLoopUnroll = true;
-
-    PMBuilder.DisableUnrollLoops = true;
-    // Loop interleaving in the loop vectorizer has historically been set to be
-    // enabled when loop unrolling is enabled.
-    PMBuilder.LoopsInterleaved = false;
-    PMBuilder.MergeFunctions = false;
-    PMBuilder.PrepareForThinLTO = false;
-    PMBuilder.PrepareForLTO = false;
-    PMBuilder.RerollLoops = false;
-  } else {
-    PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
-    PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
-    PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
-    PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
-    // Only enable CGProfilePass when using integrated assembler, since
-    // non-integrated assemblers don't recognize .cgprofile section.
-    PMBuilder.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
-
-    PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
-    // Loop interleaving in the loop vectorizer has historically been set to be
-    // enabled when loop unrolling is enabled.
-    PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
-    PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
-    PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
-    PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
-    PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
-  }
+  PMBuilder.OptLevel = CodeGenOpts.OptimizationLevel;
+  PMBuilder.SizeLevel = CodeGenOpts.OptimizeSize;
+  PMBuilder.SLPVectorize = CodeGenOpts.VectorizeSLP;
+  PMBuilder.LoopVectorize = CodeGenOpts.VectorizeLoop;
+  // Only enable CGProfilePass when using integrated assembler, since
+  // non-integrated assemblers don't recognize .cgprofile section.
+  PMBuilder.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;
+
+  PMBuilder.DisableUnrollLoops = !CodeGenOpts.UnrollLoops;
+  // Loop interleaving in the loop vectorizer has historically been set to be
+  // enabled when loop unrolling is enabled.
+  PMBuilder.LoopsInterleaved = CodeGenOpts.UnrollLoops;
+  PMBuilder.MergeFunctions = CodeGenOpts.MergeFunctions;
+  PMBuilder.PrepareForThinLTO = CodeGenOpts.PrepareForThinLTO;
+  PMBuilder.PrepareForLTO = CodeGenOpts.PrepareForLTO;
+  PMBuilder.RerollLoops = CodeGenOpts.RerollLoops;
 
   MPM.add(new TargetLibraryInfoWrapperPass(*TLII));