Bitcode: Fix reading and writing of ConstantDataVectors of halfs

In r254991 I allowed ConstantDataVectors to contain elements of
HalfTy, but I missed updating the bitcode reader and writer to handle
this, so now we crash if we try to emit bitcode on programs that have
constant vectors of half.

This fixes the issue and adds test coverage for reading and writing
constant sequences in bitcode.

llvm-svn: 256982

3 files changed, 47 insertions, 23 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index c7606fd488a..2ad4b32e315 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -2654,8 +2654,6 @@ std::error_code BitcodeReader::parseConstants() {
         return error("Invalid record");
 
       Type *EltTy = cast<SequentialType>(CurTy)->getElementType();
-      unsigned Size = Record.size();
-
       if (EltTy->isIntegerTy(8)) {
         SmallVector<uint8_t, 16> Elts(Record.begin(), Record.end());
         if (isa<VectorType>(CurTy))
@@ -2680,21 +2678,24 @@ std::error_code BitcodeReader::parseConstants() {
           V = ConstantDataVector::get(Context, Elts);
         else
           V = ConstantDataArray::get(Context, Elts);
+      } else if (EltTy->isHalfTy()) {
+        SmallVector<uint16_t, 16> Elts(Record.begin(), Record.end());
+        if (isa<VectorType>(CurTy))
+          V = ConstantDataVector::getFP(Context, Elts);
+        else
+          V = ConstantDataArray::getFP(Context, Elts);
       } else if (EltTy->isFloatTy()) {
-        SmallVector<float, 16> Elts(Size);
-        std::transform(Record.begin(), Record.end(), Elts.begin(), BitsToFloat);
+        SmallVector<uint32_t, 16> Elts(Record.begin(), Record.end());
         if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::get(Context, Elts);
+          V = ConstantDataVector::getFP(Context, Elts);
         else
-          V = ConstantDataArray::get(Context, Elts);
+          V = ConstantDataArray::getFP(Context, Elts);
       } else if (EltTy->isDoubleTy()) {
-        SmallVector<double, 16> Elts(Size);
-        std::transform(Record.begin(), Record.end(), Elts.begin(),
-                       BitsToDouble);
+        SmallVector<uint64_t, 16> Elts(Record.begin(), Record.end());
         if (isa<VectorType>(CurTy))
-          V = ConstantDataVector::get(Context, Elts);
+          V = ConstantDataVector::getFP(Context, Elts);
         else
-          V = ConstantDataArray::get(Context, Elts);
+          V = ConstantDataArray::getFP(Context, Elts);
       } else {
         return error("Invalid type for value");
       }
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index a1f87863757..a899a0cc3ee 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1630,19 +1630,10 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
       if (isa<IntegerType>(EltTy)) {
         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
           Record.push_back(CDS->getElementAsInteger(i));
-      } else if (EltTy->isFloatTy()) {
-        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
-          union { float F; uint32_t I; };
-          F = CDS->getElementAsFloat(i);
-          Record.push_back(I);
-        }
       } else {
-        assert(EltTy->isDoubleTy() && "Unknown ConstantData element type");
-        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i) {
-          union { double F; uint64_t I; };
-          F = CDS->getElementAsDouble(i);
-          Record.push_back(I);
-        }
+        for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
+          Record.push_back(
+              CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
       }
     } else if (isa<ConstantArray>(C) || isa<ConstantStruct>(C) ||
                isa<ConstantVector>(C)) {
diff --git a/llvm/test/Bitcode/constant-sequence.ll b/llvm/test/Bitcode/constant-sequence.ll
new file mode 100644
index 00000000000..51e3b0051e0
--- /dev/null
+++ b/llvm/test/Bitcode/constant-sequence.ll
@@ -0,0 +1,32 @@
+; Round trip constant sequences through bitcode
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+; CHECK: @array.i8  = constant [3 x i8] c"\00\01\00"
+@array.i8  = constant [3 x i8] [i8 -0, i8 1, i8 0]
+; CHECK: @array.i16 = constant [3 x i16] [i16 0, i16 1, i16 0]
+@array.i16 = constant [3 x i16] [i16 -0, i16 1, i16 0]
+; CHECK: @array.i32 = constant [3 x i32] [i32 0, i32 1, i32 0]
+@array.i32 = constant [3 x i32] [i32 -0, i32 1, i32 0]
+; CHECK: @array.i64 = constant [3 x i64] [i64 0, i64 1, i64 0]
+@array.i64 = constant [3 x i64] [i64 -0, i64 1, i64 0]
+; CHECK: @array.f16 = constant [3 x half] [half 0xH8000, half 0xH3C00, half 0xH0000]
+@array.f16 = constant [3 x half] [half -0.0, half 1.0, half 0.0]
+; CHECK: @array.f32 = constant [3 x float] [float -0.000000e+00, float 1.000000e+00, float 0.000000e+00]
+@array.f32 = constant [3 x float] [float -0.0, float 1.0, float 0.0]
+; CHECK: @array.f64 = constant [3 x double] [double -0.000000e+00, double 1.000000e+00, double 0.000000e+00]
+@array.f64 = constant [3 x double] [double -0.0, double 1.0, double 0.0]
+
+; CHECK: @vector.i8  = constant <3 x i8>  <i8 0, i8 1, i8 0>
+@vector.i8  = constant <3 x i8>  <i8 -0, i8 1, i8 0>
+; CHECK: @vector.i16 = constant <3 x i16> <i16 0, i16 1, i16 0>
+@vector.i16 = constant <3 x i16> <i16 -0, i16 1, i16 0>
+; CHECK: @vector.i32 = constant <3 x i32> <i32 0, i32 1, i32 0>
+@vector.i32 = constant <3 x i32> <i32 -0, i32 1, i32 0>
+; CHECK: @vector.i64 = constant <3 x i64> <i64 0, i64 1, i64 0>
+@vector.i64 = constant <3 x i64> <i64 -0, i64 1, i64 0>
+; CHECK: @vector.f16 = constant <3 x half> <half 0xH8000, half 0xH3C00, half 0xH0000>
+@vector.f16 = constant <3 x half> <half -0.0, half 1.0, half 0.0>
+; CHECK: @vector.f32 = constant <3 x float> <float -0.000000e+00, float 1.000000e+00, float 0.000000e+00>
+@vector.f32 = constant <3 x float> <float -0.0, float 1.0, float 0.0>
+; CHECK: @vector.f64 = constant <3 x double> <double -0.000000e+00, double 1.000000e+00, double 0.000000e+00>
+@vector.f64 = constant <3 x double> <double -0.0, double 1.0, double 0.0>