[APInt][PatternMatch] Add 'is non-positive' predicate

It will be useful for implementing the fold mentioned in
https://bugs.llvm.org/show_bug.cgi?id=44100#c4

1 files changed, 24 insertions, 0 deletions

diff --git a/llvm/unittests/IR/PatternMatch.cpp b/llvm/unittests/IR/PatternMatch.cpp
index 0c2ec36f878..80e0e92615a 100644
--- a/llvm/unittests/IR/PatternMatch.cpp
+++ b/llvm/unittests/IR/PatternMatch.cpp
@@ -182,6 +182,30 @@ TEST_F(PatternMatchTest, SpecificIntUGT) {
           .match(NegOne));
 }
 
+TEST_F(PatternMatchTest, SignbitZeroChecks) {
+  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_TRUE(m_Negative().match(NegOne));
+  EXPECT_FALSE(m_NonNegative().match(NegOne));
+  EXPECT_FALSE(m_StrictlyPositive().match(NegOne));
+  EXPECT_TRUE(m_NonPositive().match(NegOne));
+
+  EXPECT_FALSE(m_Negative().match(Zero));
+  EXPECT_TRUE(m_NonNegative().match(Zero));
+  EXPECT_FALSE(m_StrictlyPositive().match(Zero));
+  EXPECT_TRUE(m_NonPositive().match(Zero));
+
+  EXPECT_FALSE(m_Negative().match(One));
+  EXPECT_TRUE(m_NonNegative().match(One));
+  EXPECT_TRUE(m_StrictlyPositive().match(One));
+  EXPECT_FALSE(m_NonPositive().match(One));
+}
+
 TEST_F(PatternMatchTest, SpecificIntUGE) {
   Type *IntTy = IRB.getInt32Ty();
   unsigned BitWidth = IntTy->getScalarSizeInBits();