llvm-reduce: Add pass to reduce instructions

Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D66263

llvm-svn: 372282

2 files changed, 86 insertions, 0 deletions

diff --git a/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp b/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp
new file mode 100644
index 00000000000..c6b798236e5
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp
@@ -0,0 +1,66 @@
+//===- ReduceArguments.cpp - Specialized Delta Pass -----------------------===//
+//
+// 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 a function which calls the Generic Delta pass in order
+// to reduce uninteresting Arguments from defined functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ReduceInstructions.h"
+
+using namespace llvm;
+
+/// Removes out-of-chunk arguments from functions, and modifies their calls
+/// accordingly. It also removes allocations of out-of-chunk arguments.
+/// @returns the Module stripped of out-of-chunk functions
+static void extractInstrFromModule(std::vector<Chunk> ChunksToKeep,
+                                   Module *Program) {
+  int I = 0, InstCount = 0;
+  std::set<Instruction *> InstToKeep;
+
+  for (auto &F : *Program)
+    for (auto &BB : F)
+      for (auto &Inst : BB)
+        if (I < (int)ChunksToKeep.size()) {
+          if (ChunksToKeep[I].contains(++InstCount))
+            InstToKeep.insert(&Inst);
+          if (ChunksToKeep[I].end == InstCount)
+            ++I;
+        }
+
+  std::vector<Instruction *> InstToDelete;
+  for (auto &F : *Program)
+    for (auto &BB : F)
+      for (auto &Inst : BB)
+        if (!InstToKeep.count(&Inst)) {
+          Inst.replaceAllUsesWith(UndefValue::get(Inst.getType()));
+          InstToDelete.push_back(&Inst);
+        }
+
+  for (auto &I : InstToDelete)
+    I->eraseFromParent();
+}
+
+/// Counts the amount of basic blocks and prints their name & respective index
+static unsigned countInstructions(Module *Program) {
+  // TODO: Silence index with --quiet flag
+  outs() << "----------------------------\n";
+  int InstCount = 0;
+  for (auto &F : *Program)
+    for (auto &BB : F)
+        InstCount += BB.getInstList().size();
+  outs() << "Number of instructions: " << InstCount << "\n";
+
+  return InstCount;
+}
+
+void llvm::reduceInstructionsDeltaPass(TestRunner &Test) {
+  outs() << "*** Reducing Insructions...\n";
+  unsigned InstCount = countInstructions(Test.getProgram());
+  runDeltaPass(Test, InstCount, extractInstrFromModule);
+}
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceInstructions.h b/llvm/tools/llvm-reduce/deltas/ReduceInstructions.h
new file mode 100644
index 00000000000..a9266acd051
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceInstructions.h
@@ -0,0 +1,20 @@
+//===- ReduceArguments.h - Specialized Delta Pass -------------------------===//
+//
+// 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 a function which calls the Generic Delta pass in order
+// to reduce uninteresting Arguments from defined functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Delta.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+
+namespace llvm {
+void reduceInstructionsDeltaPass(TestRunner &Test);
+} // namespace llvm