Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 68 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Analysis/ScalarEvolutionNormalization.h b/clang-r353983/include/llvm/Analysis/ScalarEvolutionNormalization.h
new file mode 100644
index 00000000..1a05594a
--- /dev/null
+++ b/clang-r353983/include/llvm/Analysis/ScalarEvolutionNormalization.h
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+//===- llvm/Analysis/ScalarEvolutionNormalization.h - See below -*- 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 defines utilities for working with "normalized" ScalarEvolution
+// expressions.
+//
+// The following example illustrates post-increment uses and how normalized
+// expressions help.
+//
+//   for (i=0; i!=n; ++i) {
+//     ...
+//   }
+//   use(i);
+//
+// While the expression for most uses of i inside the loop is {0,+,1}<%L>, the
+// expression for the use of i outside the loop is {1,+,1}<%L>, since i is
+// incremented at the end of the loop body. This is inconveient, since it
+// suggests that we need two different induction variables, one that starts
+// at 0 and one that starts at 1. We'd prefer to be able to think of these as
+// the same induction variable, with uses inside the loop using the
+// "pre-incremented" value, and uses after the loop using the
+// "post-incremented" value.
+//
+// Expressions for post-incremented uses are represented as an expression
+// paired with a set of loops for which the expression is in "post-increment"
+// mode (there may be multiple loops).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONNORMALIZATION_H
+#define LLVM_ANALYSIS_SCALAREVOLUTIONNORMALIZATION_H
+
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+
+namespace llvm {
+
+class Loop;
+class ScalarEvolution;
+class SCEV;
+
+typedef SmallPtrSet<const Loop *, 2> PostIncLoopSet;
+
+typedef function_ref<bool(const SCEVAddRecExpr *)> NormalizePredTy;
+
+/// Normalize \p S to be post-increment for all loops present in \p
+/// Loops.
+const SCEV *normalizeForPostIncUse(const SCEV *S, const PostIncLoopSet &Loops,
+                                   ScalarEvolution &SE);
+
+/// Normalize \p S for all add recurrence sub-expressions for which \p
+/// Pred returns true.
+const SCEV *normalizeForPostIncUseIf(const SCEV *S, NormalizePredTy Pred,
+                                     ScalarEvolution &SE);
+
+/// Denormalize \p S to be post-increment for all loops present in \p
+/// Loops.
+const SCEV *denormalizeForPostIncUse(const SCEV *S, const PostIncLoopSet &Loops,
+                                     ScalarEvolution &SE);
+} // namespace llvm
+
+#endif