Adding splitdouble HLSL function (#109331)

- Adding hlsl `splitdouble` intrinsics
- Adding DXIL lowering
- Adding SPIRV lowering
- Adding test

Fixes: #108901

---------

Co-authored-by: Joao Saffran <jderezende@microsoft.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index e0ea65bcaf36..e90e8da3e9f1 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -5460,9 +5460,8 @@ LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
   return getOrCreateOpaqueLValueMapping(e);
 }
 
-void CodeGenFunction::EmitHLSLOutArgExpr(const HLSLOutArgExpr *E,
-                                         CallArgList &Args, QualType Ty) {
-
+std::pair<LValue, LValue>
+CodeGenFunction::EmitHLSLOutArgLValues(const HLSLOutArgExpr *E, QualType Ty) {
   // Emitting the casted temporary through an opaque value.
   LValue BaseLV = EmitLValue(E->getArgLValue());
   OpaqueValueMappingData::bind(*this, E->getOpaqueArgLValue(), BaseLV);
@@ -5476,6 +5475,13 @@ void CodeGenFunction::EmitHLSLOutArgExpr(const HLSLOutArgExpr *E,
                                TempLV);
 
   OpaqueValueMappingData::bind(*this, E->getCastedTemporary(), TempLV);
+  return std::make_pair(BaseLV, TempLV);
+}
+
+LValue CodeGenFunction::EmitHLSLOutArgExpr(const HLSLOutArgExpr *E,
+                                           CallArgList &Args, QualType Ty) {
+
+  auto [BaseLV, TempLV] = EmitHLSLOutArgLValues(E, Ty);
 
   llvm::Value *Addr = TempLV.getAddress().getBasePointer();
   llvm::Type *ElTy = ConvertTypeForMem(TempLV.getType());
@@ -5488,6 +5494,7 @@ void CodeGenFunction::EmitHLSLOutArgExpr(const HLSLOutArgExpr *E,
   Args.addWriteback(BaseLV, TmpAddr, nullptr, E->getWritebackCast(),
                     LifetimeSize);
   Args.add(RValue::get(TmpAddr, *this), Ty);
+  return TempLV;
 }
 
 LValue