1 files changed, 164 insertions, 0 deletions
diff --git a/llvm/lib/Target/PowerPC/PPCLowerMASSVEntries.cpp b/llvm/lib/Target/PowerPC/PPCLowerMASSVEntries.cpp
new file mode 100644
index 0000000000000..83cca11b27a37
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+++ b/llvm/lib/Target/PowerPC/PPCLowerMASSVEntries.cpp
@@ -0,0 +1,164 @@
+//===-- PPCLowerMASSVEntries.cpp ------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements lowering of MASSV (SIMD) entries for specific PowerPC
+// subtargets.
+// Following is an example of a conversion specific to Power9 subtarget:
+// __sind2_massv ---> __sind2_P9
+//
+//===----------------------------------------------------------------------===//
+
+#include "PPC.h"
+#include "PPCSubtarget.h"
+#include "PPCTargetMachine.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+
+#define DEBUG_TYPE "ppc-lower-massv-entries"
+
+using namespace llvm;
+
+namespace {
+
+// Length of the suffix "massv", which is specific to IBM MASSV library entries.
+const unsigned MASSVSuffixLength = 5;
+
+static StringRef MASSVFuncs[] = {
+#define TLI_DEFINE_MASSV_VECFUNCS_NAMES
+#include "llvm/Analysis/VecFuncs.def"
+};
+
+class PPCLowerMASSVEntries : public ModulePass {
+public:
+  static char ID;
+
+  PPCLowerMASSVEntries() : ModulePass(ID) {}
+
+  bool runOnModule(Module &M) override;
+
+  StringRef getPassName() const override { return "PPC Lower MASS Entries"; }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<TargetTransformInfoWrapperPass>();
+  }
+
+private:
+  static bool isMASSVFunc(StringRef Name);
+  static StringRef getCPUSuffix(const PPCSubtarget *Subtarget);
+  static std::string createMASSVFuncName(Function &Func,
+                                         const PPCSubtarget *Subtarget);
+  bool lowerMASSVCall(CallInst *CI, Function &Func, Module &M,
+                      const PPCSubtarget *Subtarget);
+};
+
+} // namespace
+
+/// Checks if the specified function name represents an entry in the MASSV
+/// library.
+bool PPCLowerMASSVEntries::isMASSVFunc(StringRef Name) {
+  auto Iter = std::find(std::begin(MASSVFuncs), std::end(MASSVFuncs), Name);
+  return Iter != std::end(MASSVFuncs);
+}
+
+// FIXME:
+/// Returns a string corresponding to the specified PowerPC subtarget. e.g.:
+/// "P8" for Power8, "P9" for Power9. The string is used as a suffix while
+/// generating subtarget-specific MASSV library functions. Current support
+/// includes  Power8 and Power9 subtargets.
+StringRef PPCLowerMASSVEntries::getCPUSuffix(const PPCSubtarget *Subtarget) {
+  // Assume Power8 when Subtarget is unavailable.
+  if (!Subtarget)
+    return "P8";
+  if (Subtarget->hasP9Vector())
+    return "P9";
+  if (Subtarget->hasP8Vector())
+    return "P8";
+
+  report_fatal_error("Unsupported Subtarget: MASSV is supported only on "
+                     "Power8 and Power9 subtargets.");
+}
+
+/// Creates PowerPC subtarget-specific name corresponding to the specified
+/// generic MASSV function, and the PowerPC subtarget.
+std::string
+PPCLowerMASSVEntries::createMASSVFuncName(Function &Func,
+                                          const PPCSubtarget *Subtarget) {
+  StringRef Suffix = getCPUSuffix(Subtarget);
+  auto GenericName = Func.getName().drop_back(MASSVSuffixLength).str();
+  std::string MASSVEntryName = GenericName + Suffix.str();
+  return MASSVEntryName;
+}
+
+/// Lowers generic MASSV entries to PowerPC subtarget-specific MASSV entries.
+/// e.g.: __sind2_massv --> __sind2_P9 for a Power9 subtarget.
+/// Both function prototypes and their callsites are updated during lowering.
+bool PPCLowerMASSVEntries::lowerMASSVCall(CallInst *CI, Function &Func,
+                                          Module &M,
+                                          const PPCSubtarget *Subtarget) {
+  if (CI->use_empty())
+    return false;
+
+  std::string MASSVEntryName = createMASSVFuncName(Func, Subtarget);
+  FunctionCallee FCache = M.getOrInsertFunction(
+      MASSVEntryName, Func.getFunctionType(), Func.getAttributes());
+
+  CallSite CS(CI);
+  CI->setCalledFunction(FCache);  
+
+  return true;
+}
+
+bool PPCLowerMASSVEntries::runOnModule(Module &M) {
+  bool Changed = false;
+
+  auto *TPC = getAnalysisIfAvailable<TargetPassConfig>();
+  if (!TPC)
+    return Changed;
+
+  auto &TM = TPC->getTM<PPCTargetMachine>();
+  const PPCSubtarget *Subtarget;
+
+  for (Function &Func : M) {
+    if (!Func.isDeclaration())
+      continue;
+
+    if (!isMASSVFunc(Func.getName()))
+      continue;
+
+    // Call to lowerMASSVCall() invalidates the iterator over users upon
+    // replacing the users. Precomputing the current list of users allows us to
+    // replace all the call sites.
+    SmallVector<User *, 4> MASSVUsers;
+    for (auto *User: Func.users())
+      MASSVUsers.push_back(User);
+    
+    for (auto *User : MASSVUsers) {
+      auto *CI = dyn_cast<CallInst>(User);
+      if (!CI)
+        continue;
+
+      Subtarget = &TM.getSubtarget<PPCSubtarget>(*CI->getParent()->getParent());
+      Changed |= lowerMASSVCall(CI, Func, M, Subtarget);
+    }
+  }
+
+  return Changed;
+}
+
+char PPCLowerMASSVEntries::ID = 0;
+
+char &llvm::PPCLowerMASSVEntriesID = PPCLowerMASSVEntries::ID;
+
+INITIALIZE_PASS(PPCLowerMASSVEntries, DEBUG_TYPE, "Lower MASSV entries", false,
+                false)
+
+ModulePass *llvm::createPPCLowerMASSVEntriesPass() {
+  return new PPCLowerMASSVEntries();
+}