[IR][Patternmatch] Add m_SpecificInt_ULT() predicate

Summary:
Match an integer or vector with every element unsigned less than the
Threshold. For vectors, this includes constants with undefined elements.

FIXME: is it worth generalizing this to simply take ICmpInst::Predicate?

Reviewers: craig.topper, spatel, nikic

Reviewed By: spatel

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63811

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364711 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/IR/PatternMatch.h b/include/llvm/IR/PatternMatch.h
index d310f07d336294b5bba5ff444decce610c951010..1a11af27d1a3370d71ad21ea49eae17877aa8dcc 100644 (file)
--- a/include/llvm/IR/PatternMatch.h
+++ b/include/llvm/IR/PatternMatch.h
@@ -418,6 +418,20 @@ inline cst_pred_ty<is_lowbit_mask> m_LowBitMask() {
   return cst_pred_ty<is_lowbit_mask>();
 }
 
+struct is_unsigned_less_than {
+  const APInt *Thr;
+  bool isValue(const APInt &C) { return C.ult(*Thr); }
+};
+/// Match an integer or vector with every element unsigned less than the
+/// Threshold. For vectors, this includes constants with undefined elements.
+/// FIXME: is it worth generalizing this to simply take ICmpInst::Predicate?
+inline cst_pred_ty<is_unsigned_less_than>
+m_SpecificInt_ULT(const APInt &Threshold) {
+  cst_pred_ty<is_unsigned_less_than> P;
+  P.Thr = &Threshold;
+  return P;
+}
+
 struct is_nan {
   bool isValue(const APFloat &C) { return C.isNaN(); }
 };

diff --git a/unittests/IR/PatternMatch.cpp b/unittests/IR/PatternMatch.cpp
index de47975e7c676bc4471901266664787c3439bd00..8ea7a68b27c3e84156f495a8ca44ff297b0270ee 100644 (file)
--- a/unittests/IR/PatternMatch.cpp
+++ b/unittests/IR/PatternMatch.cpp
@@ -64,6 +64,27 @@ TEST_F(PatternMatchTest, OneUse) {
   EXPECT_FALSE(m_OneUse(m_Value()).match(Leaf));
 }
 
+TEST_F(PatternMatchTest, SpecificIntULT) {
+  Type *IntTy = IRB.getInt32Ty();
+  unsigned BitWidth = IntTy->getScalarSizeInBits();
+
+  Value *Zero = ConstantInt::get(IntTy, 0);
+  Value *One = ConstantInt::get(IntTy, 1);
+  Value *NegOne = ConstantInt::get(IntTy, -1);
+
+  EXPECT_FALSE(m_SpecificInt_ULT(APInt(BitWidth, 0)).match(Zero));
+  EXPECT_FALSE(m_SpecificInt_ULT(APInt(BitWidth, 0)).match(One));
+  EXPECT_FALSE(m_SpecificInt_ULT(APInt(BitWidth, 0)).match(NegOne));
+
+  EXPECT_TRUE(m_SpecificInt_ULT(APInt(BitWidth, 1)).match(Zero));
+  EXPECT_FALSE(m_SpecificInt_ULT(APInt(BitWidth, 1)).match(One));
+  EXPECT_FALSE(m_SpecificInt_ULT(APInt(BitWidth, 1)).match(NegOne));
+
+  EXPECT_TRUE(m_SpecificInt_ULT(APInt(BitWidth, -1)).match(Zero));
+  EXPECT_TRUE(m_SpecificInt_ULT(APInt(BitWidth, -1)).match(One));
+  EXPECT_FALSE(m_SpecificInt_ULT(APInt(BitWidth, -1)).match(NegOne));
+}
+
 TEST_F(PatternMatchTest, CommutativeDeferredValue) {
   Value *X = IRB.getInt32(1);
   Value *Y = IRB.getInt32(2);