Update prebuilt Clang to r353983e.HEADq10.0

clang 9.0.5 (based on r353983e) from build 5696680.

Bug: http://b/135931688
Bug: http://b/136008926
Test: N/A
Change-Id: I922d17410047d2e2df4625615352c588ee71b203

1 files changed, 94 insertions, 0 deletions

diff --git a/clang-r353983e/include/llvm/Analysis/LoopUnrollAnalyzer.h b/clang-r353983e/include/llvm/Analysis/LoopUnrollAnalyzer.h
new file mode 100644
index 00000000..5f332e3c
--- /dev/null
+++ b/clang-r353983e/include/llvm/Analysis/LoopUnrollAnalyzer.h
@@ -0,0 +1,94 @@
+//===- llvm/Analysis/LoopUnrollAnalyzer.h - Loop Unroll Analyzer-*- C++ -*-===//
+//
+// 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 UnrolledInstAnalyzer class. It's used for predicting
+// potential effects that loop unrolling might have, such as enabling constant
+// propagation and other optimizations.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_LOOPUNROLLANALYZER_H
+#define LLVM_ANALYSIS_LOOPUNROLLANALYZER_H
+
+#include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/IR/InstVisitor.h"
+
+// This class is used to get an estimate of the optimization effects that we
+// could get from complete loop unrolling. It comes from the fact that some
+// loads might be replaced with concrete constant values and that could trigger
+// a chain of instruction simplifications.
+//
+// E.g. we might have:
+//   int a[] = {0, 1, 0};
+//   v = 0;
+//   for (i = 0; i < 3; i ++)
+//     v += b[i]*a[i];
+// If we completely unroll the loop, we would get:
+//   v = b[0]*a[0] + b[1]*a[1] + b[2]*a[2]
+// Which then will be simplified to:
+//   v = b[0]* 0 + b[1]* 1 + b[2]* 0
+// And finally:
+//   v = b[1]
+namespace llvm {
+class UnrolledInstAnalyzer : private InstVisitor<UnrolledInstAnalyzer, bool> {
+  typedef InstVisitor<UnrolledInstAnalyzer, bool> Base;
+  friend class InstVisitor<UnrolledInstAnalyzer, bool>;
+  struct SimplifiedAddress {
+    Value *Base = nullptr;
+    ConstantInt *Offset = nullptr;
+  };
+
+public:
+  UnrolledInstAnalyzer(unsigned Iteration,
+                       DenseMap<Value *, Constant *> &SimplifiedValues,
+                       ScalarEvolution &SE, const Loop *L)
+      : SimplifiedValues(SimplifiedValues), SE(SE), L(L) {
+      IterationNumber = SE.getConstant(APInt(64, Iteration));
+  }
+
+  // Allow access to the initial visit method.
+  using Base::visit;
+
+private:
+  /// A cache of pointer bases and constant-folded offsets corresponding
+  /// to GEP (or derived from GEP) instructions.
+  ///
+  /// In order to find the base pointer one needs to perform non-trivial
+  /// traversal of the corresponding SCEV expression, so it's good to have the
+  /// results saved.
+  DenseMap<Value *, SimplifiedAddress> SimplifiedAddresses;
+
+  /// SCEV expression corresponding to number of currently simulated
+  /// iteration.
+  const SCEV *IterationNumber;
+
+  /// A Value->Constant map for keeping values that we managed to
+  /// constant-fold on the given iteration.
+  ///
+  /// While we walk the loop instructions, we build up and maintain a mapping
+  /// of simplified values specific to this iteration.  The idea is to propagate
+  /// any special information we have about loads that can be replaced with
+  /// constants after complete unrolling, and account for likely simplifications
+  /// post-unrolling.
+  DenseMap<Value *, Constant *> &SimplifiedValues;
+
+  ScalarEvolution &SE;
+  const Loop *L;
+
+  bool simplifyInstWithSCEV(Instruction *I);
+
+  bool visitInstruction(Instruction &I) { return simplifyInstWithSCEV(&I); }
+  bool visitBinaryOperator(BinaryOperator &I);
+  bool visitLoad(LoadInst &I);
+  bool visitCastInst(CastInst &I);
+  bool visitCmpInst(CmpInst &I);
+  bool visitPHINode(PHINode &PN);
+};
+}
+#endif