[cfe-commits] r50892 - in /cfe/trunk: include/clang/AST/Expr.h lib/AST/Expr.cpp lib/CodeGen/CGExpr.cpp lib/CodeGen/CodeGenFunction.h lib/Sema/SemaExpr.cpp test/Parser/ocu_vector_components.c

[Chris Lattner]

On May 8, 2008, at 11:41 PM, Nate Begeman wrote:
> URL: http://llvm.org/viewvc/llvm-project?rev=50892&view=rev
> Log:
> Extend vector member references to include {.hi, .lo, .e, .o} which  
> return a
> vector of the same element type and half the width, with the high,  
> low, even,
> and odd elements respectively.
>
> Allow member references to member references, so that .hi.hi gives  
> you the high
> quarter of a vector.  This is fairly convenient syntax for some  
> insert/extract
> operations.

Nice.

> +++ cfe/trunk/include/clang/AST/Expr.h Fri May  9 01:41:27 2008
> @@ -23,6 +23,8 @@
> #include "llvm/ADT/APFloat.h"
> #include <vector>
>
> +class llvm::Constant;

libast shouldn't depend on vmcore as we discussed.

> +++ cfe/trunk/lib/AST/Expr.cpp Fri May  9 01:41:27 2008
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> = 
> ======================================================================
> --- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExpr.cpp Fri May  9 01:41:27 2008
> @@ -460,9 +460,28 @@
> EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
>   // Emit the base vector as an l-value.
>   LValue Base = EmitLValue(E->getBase());
> +
> +  if (Base.isExtVectorElt()) {
> +    llvm::Constant *BaseElts = Base.getExtVectorElts();
> +    llvm::Constant *ExprElts = E->getEncodedElementAccess();
> +
> +    llvm::SmallVector<llvm::Constant *, 8> Indices;
> +
> +    for (unsigned i = 0, e = E->getNumElements(); i != e; ++i) {
> +      unsigned Idx = ExtVectorElementExpr::getAccessedFieldNo(i,  
> ExprElts);
> +
> +      if (isa<llvm::ConstantAggregateZero>(BaseElts))
> +         
> Indices.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
> +      else
> +        Indices.push_back(cast<llvm::ConstantInt>(BaseElts- 
> >getOperand(Idx)));
> +    }
> +    llvm::Constant *NewElts =  
> llvm::ConstantVector::get(&Indices[0], Indices.size());
> +    return LValue::MakeExtVectorElt(Base.getExtVectorAddr(),  
> NewElts);
> +  }
> +
>   assert(Base.isSimple() && "Can only subscript lvalue vectors  
> here!");
>
> -  return LValue::MakeExtVectorElt(Base.getAddress(),
> +  return LValue::MakeExtVectorElt(Base.getAddress(),
>                                   E->getEncodedElementAccess());


Please handle the 'simple' case first, so that the code is nested less:

if (issimple) {
   ..
   return dosimplestuff();
}

assert(isextvectorelet)
...

Can you use your new predicate instead of checking  
ConstantAggregateZero explicitly here?  Maybe this issue goes away  
when you switch to SmallVector in the AST.

Overall, very nice!

-Chris