Add support for lowering floating-point globals

Author: andykaylor

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -75,7 +75,11 @@ mlir::LogicalResult CIRToLLVMGlobalOpLowering::matchAndRewrite(
   SmallVector<mlir::NamedAttribute> attributes;
 
   if (init.has_value()) {
-    if (auto intAttr = mlir::dyn_cast<cir::IntAttr>(init.value())) {
+    if (auto fltAttr = mlir::dyn_cast<cir::FPAttr>(init.value())) {
+      // Initializer is a constant floating-point number: convert to MLIR
+      // builtin constant.
+      init = rewriter.getFloatAttr(llvmType, fltAttr.getValue());
+    } else if (auto intAttr = mlir::dyn_cast<cir::IntAttr>(init.value())) {
       // Initializer is a constant array: convert it to a compatible llvm init.
       init = rewriter.getIntegerAttr(llvmType, intAttr.getValue());
     } else {
@@ -99,6 +103,27 @@ static void prepareTypeConverter(mlir::LLVMTypeConverter &converter,
     // LLVM doesn't work with signed types, so we drop the CIR signs here.
     return mlir::IntegerType::get(type.getContext(), type.getWidth());
   });
+  converter.addConversion([&](cir::SingleType type) -> mlir::Type {
+    return mlir::Float32Type::get(type.getContext());
+  });
+  converter.addConversion([&](cir::DoubleType type) -> mlir::Type {
+    return mlir::Float64Type::get(type.getContext());
+  });
+  converter.addConversion([&](cir::FP80Type type) -> mlir::Type {
+    return mlir::Float80Type::get(type.getContext());
+  });
+  converter.addConversion([&](cir::FP128Type type) -> mlir::Type {
+    return mlir::Float128Type::get(type.getContext());
+  });
+  converter.addConversion([&](cir::LongDoubleType type) -> mlir::Type {
+    return converter.convertType(type.getUnderlying());
+  });
+  converter.addConversion([&](cir::FP16Type type) -> mlir::Type {
+    return mlir::Float16Type::get(type.getContext());
+  });
+  converter.addConversion([&](cir::BF16Type type) -> mlir::Type {
+    return mlir::BFloat16Type::get(type.getContext());
+  });
 }
 
 void ConvertCIRToLLVMPass::runOnOperation() {

clang/test/CIR/Lowering/global-var-simple.cpp

@@ -61,3 +61,21 @@ _BitInt(20) sb20;
 
 unsigned _BitInt(48) ub48;
 // CHECK: @ub48 = external dso_local global i48
+
+_Float16 f16;
+// CHECK: @f16 = external dso_local global half
+
+__bf16 bf16;
+// CHECK: @bf16 = external dso_local global bfloat
+
+float f;
+// CHECK: @f = external dso_local global float
+
+double d = 1.25;
+// CHECK: @d = dso_local global double 1.250000e+00
+
+long double ld;
+// CHECK: @ld = external dso_local global x86_fp80
+
+__float128 f128;
+// CHECK: @f128 = external dso_local global fp128