[cfe-commits] r39725 - in /cfe/cfe/trunk/CodeGen: CGExpr.cpp CodeGenFunction.h

[clattner at cs.uiuc.edu]

Author: clattner
Date: Wed Jul 11 11:47:34 2007
New Revision: 39725

URL: http://llvm.org/viewvc/llvm-project?rev=39725&view=rev
Log:
implement codegen support for rvalue-only vector subscripts, such as:

float4 test(void);
float test2() {
  return test()[1];
}

Modified:
    cfe/cfe/trunk/CodeGen/CGExpr.cpp
    cfe/cfe/trunk/CodeGen/CodeGenFunction.h

Modified: cfe/cfe/trunk/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/cfe/trunk/CodeGen/CGExpr.cpp?rev=39725&r1=39724&r2=39725&view=diff

==============================================================================
--- cfe/cfe/trunk/CodeGen/CGExpr.cpp (original)
+++ cfe/cfe/trunk/CodeGen/CGExpr.cpp Wed Jul 11 11:47:34 2007
@@ -453,10 +453,9 @@
     if (const EnumConstantDecl *EC = 
           dyn_cast<EnumConstantDecl>(cast<DeclRefExpr>(E)->getDecl()))
       return RValue::get(llvm::ConstantInt::get(EC->getInitVal()));
-    
-    // FALLTHROUGH
-  case Expr::ArraySubscriptExprClass:
     return EmitLoadOfLValue(E);
+  case Expr::ArraySubscriptExprClass:
+    return EmitArraySubscriptExprRV(cast<ArraySubscriptExpr>(E));
   case Expr::StringLiteralClass:
     return RValue::get(EmitLValue(E).getAddress());
     
@@ -489,6 +488,29 @@
                                            E->getValue()));
 }
 
+
+RValue CodeGenFunction::EmitArraySubscriptExprRV(const ArraySubscriptExpr *E) {
+  // Emit subscript expressions in rvalue context's.  For most cases, this just
+  // loads the lvalue formed by the subscript expr.  However, we have to be
+  // careful, because the base of a vector subscript is occasionally an rvalue,
+  // so we can't get it as an lvalue.
+  if (!E->getBase()->getType()->isVectorType())
+    return EmitLoadOfLValue(E);
+
+  // Handle the vector case.  The base must be a vector, the index must be an
+  // integer value.
+  QualType BaseTy, IdxTy;
+  llvm::Value *Base =
+    EmitExprWithUsualUnaryConversions(E->getBase(), BaseTy).getVal();
+  llvm::Value *Idx = 
+    EmitExprWithUsualUnaryConversions(E->getIdx(), IdxTy).getVal();
+  
+  // FIXME: Convert Idx to i32 type.
+  
+  return RValue::get(Builder.CreateExtractElement(Base, Idx, "vecext"));
+}
+
+
 RValue CodeGenFunction::EmitCastExpr(const CastExpr *E) {
   QualType SrcTy;
   RValue Src = EmitExprWithUsualUnaryConversions(E->getSubExpr(), SrcTy);

Modified: cfe/cfe/trunk/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/cfe/trunk/CodeGen/CodeGenFunction.h?rev=39725&r1=39724&r2=39725&view=diff

==============================================================================
--- cfe/cfe/trunk/CodeGen/CodeGenFunction.h (original)
+++ cfe/cfe/trunk/CodeGen/CodeGenFunction.h Wed Jul 11 11:47:34 2007
@@ -312,6 +312,7 @@
   
   RValue EmitCastExpr(const CastExpr *E);
   RValue EmitCallExpr(const CallExpr *E);
+  RValue EmitArraySubscriptExprRV(const ArraySubscriptExpr *E);
 
   // Unary Operators.
   RValue EmitUnaryOperator(const UnaryOperator *E);