[NFC] Delete some dead/unreachable code in CGCall (microsoft#5069)

This code is all unreachable. Reverting this strips out some cascading
changes adding an unused parameter to a few functions.

tools/clang/lib/CodeGen/CGCall.cpp

@@ -988,17 +988,13 @@ static llvm::Value *CreateCoercedLoad(llvm::Value *SrcPtr,
 // FIXME: Do we need to recurse here?
 static void BuildAggStore(CodeGenFunction &CGF, llvm::Value *Val,
                           llvm::Value *DestPtr, bool DestIsVolatile,
-                          CharUnits DestAlign,
-                          QualType QTy // HLSL Change
-                          ) {
+                          CharUnits DestAlign) {
   // Prefer scalar stores to first-class aggregate stores.
   if (llvm::StructType *STy =
         dyn_cast<llvm::StructType>(Val->getType())) {
     // HLSL Change Begins
-    if (CGF.getLangOpts().HLSL) {
-      CGF.CGM.getHLSLRuntime().EmitHLSLAggregateStore(CGF, Val, DestPtr, QTy);
-      return;
-    }
+    assert(!CGF.getLangOpts().HLSL &&
+           "HLSL uses SRet so this should not be possible to reach.");
     // HLSL Change Ends
     const llvm::StructLayout *Layout =
       CGF.CGM.getDataLayout().getStructLayout(STy);
@@ -1028,9 +1024,7 @@ static void CreateCoercedStore(llvm::Value *Src,
                                llvm::Value *DstPtr,
                                bool DstIsVolatile,
                                CharUnits DstAlign,
-                               CodeGenFunction &CGF,
-                               QualType QTy // HLSL Change
-                               ) {
+                               CodeGenFunction &CGF) {
   llvm::Type *SrcTy = Src->getType();
   llvm::Type *DstTy =
     cast<llvm::PointerType>(DstPtr->getType())->getElementType();
@@ -1063,7 +1057,7 @@ static void CreateCoercedStore(llvm::Value *Src,
   if (SrcSize <= DstSize) {
     llvm::Value *Casted =
       CGF.Builder.CreateBitCast(DstPtr, llvm::PointerType::getUnqual(SrcTy));
-    BuildAggStore(CGF, Src, Casted, DstIsVolatile, DstAlign, QTy);  // HLSL Change - Add QTy
+    BuildAggStore(CGF, Src, Casted, DstIsVolatile, DstAlign);
   } else {
     // Otherwise do coercion through memory. This is stupid, but
     // simple.
@@ -2082,7 +2076,7 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
         assert(NumIRArgs == 1);
         auto AI = FnArgs[FirstIRArg];
         AI->setName(Arg->getName() + ".coerce");
-        CreateCoercedStore(AI, Ptr, /*DestIsVolatile=*/false, PtrAlign, *this, Ty); // HLSL Change - Add Ty.
+        CreateCoercedStore(AI, Ptr, /*DestIsVolatile=*/false, PtrAlign, *this);
       }
 
 
@@ -3724,7 +3718,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
             DestPtr = CreateMemTemp(RetTy, "agg.tmp");
             DestIsVolatile = false;
           }
-          BuildAggStore(*this, CI, DestPtr, DestIsVolatile, DestAlign, RetTy); // HLSL Change - Add QualTy.
+          BuildAggStore(*this, CI, DestPtr, DestIsVolatile, DestAlign);
           return RValue::getAggregate(DestPtr);
         }
         case TEK_Scalar: {
@@ -3760,7 +3754,7 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
         StoreAlign =
           StoreAlign.alignmentAtOffset(CharUnits::fromQuantity(Offs));
       }
-      CreateCoercedStore(CI, StorePtr, DestIsVolatile, StoreAlign, *this, RetTy); // HLSL Change - Add QTy.
+      CreateCoercedStore(CI, StorePtr, DestIsVolatile, StoreAlign, *this);
 
       return convertTempToRValue(DestPtr, RetTy, SourceLocation());
     }

tools/clang/lib/CodeGen/CGHLSLMS.cpp

@@ -270,10 +270,6 @@ class CGMSHLSLRuntime : public CGHLSLRuntime {
                                    llvm::Value *DestPtr,
                                    clang::QualType Ty) override;
 
-  void EmitHLSLAggregateStore(CodeGenFunction &CGF, llvm::Value *Val,
-                                   llvm::Value *DestPtr,
-                                   clang::QualType Ty) override;
-
   void EmitHLSLFlatConversion(CodeGenFunction &CGF, Value *Val,
                               Value *DestPtr,
                               QualType Ty,
@@ -5691,9 +5687,9 @@ void CGMSHLSLRuntime::EmitHLSLFlatConversionAggregateCopy(CodeGenFunction &CGF,
     }
   }
 
-  // It is possible to implement EmitHLSLAggregateCopy, EmitHLSLAggregateStore
-  // the same way. But split value to scalar will generate many instruction when
-  // src type is same as dest type.
+  // It is possible to implement EmitHLSLAggregateCopy, the same way. But split
+  // value to scalar will generate many instruction when src type is same as
+  // dest type.
   SmallVector<Value *, 4> GEPIdxStack;
   SmallVector<Value *, 4> SrcPtrs;
   SmallVector<QualType, 4> SrcQualTys;
@@ -5712,12 +5708,6 @@ void CGMSHLSLRuntime::EmitHLSLFlatConversionAggregateCopy(CodeGenFunction &CGF,
   ConvertAndStoreElements(CGF, SrcVals, SrcQualTys, DstPtrs, DstQualTys);
 }
 
-void CGMSHLSLRuntime::EmitHLSLAggregateStore(CodeGenFunction &CGF, llvm::Value *SrcVal,
-    llvm::Value *DestPtr,
-    clang::QualType Ty) {
-    DXASSERT(0, "aggregate return type will use SRet, no aggregate store should exist");
-}
-
 // Either copies a scalar to a scalar, a scalar to a vector, or splats a scalar to a vector
 static void SimpleFlatValCopy(CodeGenFunction &CGF, 
     Value *SrcVal, QualType SrcQualTy, Value *DstPtr, QualType DstQualTy) {

tools/clang/lib/CodeGen/CGHLSLRuntime.h

@@ -114,9 +114,6 @@ class CGHLSLRuntime {
   virtual void EmitHLSLAggregateCopy(CodeGenFunction &CGF, llvm::Value *SrcPtr,
                                    llvm::Value *DestPtr,
                                    clang::QualType Ty) = 0;
-  virtual void EmitHLSLAggregateStore(CodeGenFunction &CGF, llvm::Value *Val,
-                                   llvm::Value *DestPtr,
-                                   clang::QualType Ty) = 0;
   virtual void EmitHLSLFlatConversion(CodeGenFunction &CGF, llvm::Value *Val,
                                    llvm::Value *DestPtr,
                                    clang::QualType Ty, clang::QualType SrcTy) = 0;