"I got annoyed at the compiler warnings from ConstantInt::get(Ty, -1,

true), and casts make me nervous and are verbose anyway, so here's a
ConstantInt::getSigned(Ty, int64_t) method. Just overloading
ConstantInt::get() to take an int64_t too would cause ambiguous
overload errors."

Patch by Jeffrey Yasskin!

llvm-svn: 69958

2 files changed, 23 insertions, 0 deletions

diff --git a/llvm/include/llvm/Constants.h b/llvm/include/llvm/Constants.h
index 0f4c29a0587..e04a6cf67d8 100644
--- a/llvm/include/llvm/Constants.h
+++ b/llvm/include/llvm/Constants.h
@@ -110,6 +110,15 @@ public:
   /// @brief Get a ConstantInt for a specific value.
   static ConstantInt *get(const Type *Ty, uint64_t V, bool isSigned = false);
 
+  /// Return a ConstantInt with the specified value for the specified type. The
+  /// value V will be canonicalized to a an unsigned APInt. Accessing it with
+  /// either getSExtValue() or getZExtValue() will yield a correctly sized and
+  /// signed value for the type Ty.
+  /// @brief Get a ConstantInt for a specific signed value.
+  static ConstantInt *getSigned(const Type *Ty, int64_t V) {
+    return get(Ty, V, true);
+  }
+
   /// Return a ConstantInt with the specified value and an implied Type. The
   /// type is the integer type that corresponds to the bit width of the value.
   static ConstantInt *get(const APInt &V);
diff --git a/llvm/unittests/VMCore/ConstantsTest.cpp b/llvm/unittests/VMCore/ConstantsTest.cpp
index c40dc7e4715..519d928eac1 100644
--- a/llvm/unittests/VMCore/ConstantsTest.cpp
+++ b/llvm/unittests/VMCore/ConstantsTest.cpp
@@ -19,6 +19,7 @@ TEST(ConstantsTest, Integer_i1) {
   Constant* One = ConstantInt::get(Int1, 1, true);
   Constant* Zero = ConstantInt::get(Int1, 0);
   Constant* NegOne = ConstantInt::get(Int1, static_cast<uint64_t>(-1), true);
+  EXPECT_EQ(NegOne, ConstantInt::getSigned(Int1, -1));
   Constant* Undef = UndefValue::get(Int1);
 
   // Input:  @b = constant i1 add(i1 1 , i1 1)
@@ -94,5 +95,18 @@ TEST(ConstantsTest, Integer_i1) {
   EXPECT_EQ(Zero, ConstantExpr::getSRem(One, NegOne));
 }
 
+TEST(ConstantsTest, IntSigns) {
+  const IntegerType* Int8Ty = Type::Int8Ty;
+  EXPECT_EQ(100, ConstantInt::get(Int8Ty, 100, false)->getSExtValue());
+  EXPECT_EQ(100, ConstantInt::get(Int8Ty, 100, true)->getSExtValue());
+  EXPECT_EQ(100, ConstantInt::getSigned(Int8Ty, 100)->getSExtValue());
+  EXPECT_EQ(-50, ConstantInt::get(Int8Ty, 206)->getSExtValue());
+  EXPECT_EQ(-50, ConstantInt::getSigned(Int8Ty, -50)->getSExtValue());
+  EXPECT_EQ(206U, ConstantInt::getSigned(Int8Ty, -50)->getZExtValue());
+
+  // Overflow is handled by truncation.
+  EXPECT_EQ(0x3b, ConstantInt::get(Int8Ty, 0x13b)->getSExtValue());
+}
+
 }  // end anonymous namespace
 }  // end namespace llvm