From ab47fa643b77923322368dc2b8f277080c988c98 Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Fri, 12 Aug 2016 22:16:05 +0000
Subject: [PATCH] Add support to paternmatch for simple const Value cases.

Pattern match has some paths which can operate on constant instructions,
but not all.  This adds a version of m_value() to return const Value* and
changes ICmp matching to use auto so that it can match both constant and
mutable instructions.

Tests also included for both mutable and constant ICmpInst matching.

This will be used in a future commit to constify ValueTracking.cpp.

llvm-svn: 278570
---
 llvm/include/llvm/IR/PatternMatch.h |  6 +++---
 llvm/unittests/IR/PatternMatch.cpp  | 27 +++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
index 7da9afcf9463..9151afd2295f 100644
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -294,10 +294,10 @@ template <typename Class> struct bind_ty {
 
 /// \brief Match a value, capturing it if we match.
 inline bind_ty<Value> m_Value(Value *&V) { return V; }
+inline bind_ty<const Value> m_Value(const Value *&V) { return V; }
 
 /// \brief Match an instruction, capturing it if we match.
 inline bind_ty<Instruction> m_Instruction(Instruction *&I) { return I; }
-
 /// \brief Match a binary operator, capturing it if we match.
 inline bind_ty<BinaryOperator> m_BinOp(BinaryOperator *&I) { return I; }
 
@@ -682,7 +682,7 @@ template <typename SubPattern_t> struct Exact_match {
   Exact_match(const SubPattern_t &SP) : SubPattern(SP) {}
 
   template <typename OpTy> bool match(OpTy *V) {
-    if (PossiblyExactOperator *PEO = dyn_cast<PossiblyExactOperator>(V))
+    if (auto *PEO = dyn_cast<PossiblyExactOperator>(V))
       return PEO->isExact() && SubPattern.match(V);
     return false;
   }
@@ -706,7 +706,7 @@ struct CmpClass_match {
       : Predicate(Pred), L(LHS), R(RHS) {}
 
   template <typename OpTy> bool match(OpTy *V) {
-    if (Class *I = dyn_cast<Class>(V))
+    if (auto *I = dyn_cast<Class>(V))
       if (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) {
         Predicate = I->getPredicate();
         return true;
diff --git a/llvm/unittests/IR/PatternMatch.cpp b/llvm/unittests/IR/PatternMatch.cpp
index 1121d6554db7..2d1321def7e3 100644
--- a/llvm/unittests/IR/PatternMatch.cpp
+++ b/llvm/unittests/IR/PatternMatch.cpp
@@ -295,4 +295,31 @@ TEST_F(PatternMatchTest, OverflowingBinOps) {
   EXPECT_FALSE(m_NUWShl(m_Value(), m_Value()).match(IRB.CreateNUWAdd(L, R)));
 }
 
+template <typename T> struct MutableConstTest : PatternMatchTest { };
+
+typedef ::testing::Types<std::tuple<Value*, Instruction*>,
+                         std::tuple<const Value*, const Instruction *>>
+    MutableConstTestTypes;
+TYPED_TEST_CASE(MutableConstTest, MutableConstTestTypes);
+
+TYPED_TEST(MutableConstTest, ICmp) {
+  auto &IRB = PatternMatchTest::IRB;
+
+  typedef typename std::tuple_element<0, TypeParam>::type ValueType;
+  typedef typename std::tuple_element<1, TypeParam>::type InstructionType;
+
+  Value *L = IRB.getInt32(1);
+  Value *R = IRB.getInt32(2);
+  ICmpInst::Predicate Pred = ICmpInst::ICMP_UGT;
+
+  ValueType MatchL;
+  ValueType MatchR;
+  ICmpInst::Predicate MatchPred;
+
+  EXPECT_TRUE(m_ICmp(MatchPred, m_Value(MatchL), m_Value(MatchR))
+              .match((InstructionType)IRB.CreateICmp(Pred, L, R)));
+  EXPECT_EQ(L, MatchL);
+  EXPECT_EQ(R, MatchR);
+}
+
 } // anonymous namespace.