Extend __builtin_shufflevector to expose the full power of the llvm shufflevector instruction. This means it can now be used for vector truncation and concatenation. This will be used for the ARM NEON implementation.

llvm-svn: 105589

1 files changed, 38 insertions, 28 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index d47f2ce8edc..7fa5762f06a 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -633,45 +633,53 @@ bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
 // This is declared to take (...), so we have to check everything.
 Action::OwningExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
-  if (TheCall->getNumArgs() < 3)
+  if (TheCall->getNumArgs() < 2)
     return ExprError(Diag(TheCall->getLocEnd(),
                           diag::err_typecheck_call_too_few_args_at_least)
-      << 0 /*function call*/ << 3 << TheCall->getNumArgs()
+      << 0 /*function call*/ << 2 << TheCall->getNumArgs()
       << TheCall->getSourceRange());
 
-  unsigned numElements = std::numeric_limits<unsigned>::max();
+  // Determine which of the following types of shufflevector we're checking:
+  // 1) unary, vector mask: (lhs, mask)
+  // 2) binary, vector mask: (lhs, rhs, mask)
+  // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
+  QualType resType = TheCall->getArg(0)->getType();
+  unsigned numElements = 0;
+  
   if (!TheCall->getArg(0)->isTypeDependent() &&
       !TheCall->getArg(1)->isTypeDependent()) {
-    QualType FAType = TheCall->getArg(0)->getType();
-    QualType SAType = TheCall->getArg(1)->getType();
-
-    if (!FAType->isVectorType() || !SAType->isVectorType()) {
+    QualType LHSType = TheCall->getArg(0)->getType();
+    QualType RHSType = TheCall->getArg(1)->getType();
+    
+    if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
       Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
         << SourceRange(TheCall->getArg(0)->getLocStart(),
                        TheCall->getArg(1)->getLocEnd());
       return ExprError();
     }
-
-    if (!Context.hasSameUnqualifiedType(FAType, SAType)) {
+    
+    numElements = LHSType->getAs<VectorType>()->getNumElements();
+    unsigned numResElements = TheCall->getNumArgs() - 2;
+
+    // Check to see if we have a call with 2 vector arguments, the unary shuffle
+    // with mask.  If so, verify that RHS is an integer vector type with the
+    // same number of elts as lhs.
+    if (TheCall->getNumArgs() == 2) {
+      if (!RHSType->isIntegerType() || 
+          RHSType->getAs<VectorType>()->getNumElements() != numElements)
+        Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
+          << SourceRange(TheCall->getArg(1)->getLocStart(),
+                         TheCall->getArg(1)->getLocEnd());
+      numResElements = numElements;
+    }
+    else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
       Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
         << SourceRange(TheCall->getArg(0)->getLocStart(),
                        TheCall->getArg(1)->getLocEnd());
       return ExprError();
-    }
-
-    numElements = FAType->getAs<VectorType>()->getNumElements();
-    if (TheCall->getNumArgs() != numElements+2) {
-      if (TheCall->getNumArgs() < numElements+2)
-        return ExprError(Diag(TheCall->getLocEnd(),
-                              diag::err_typecheck_call_too_few_args)
-                 << 0 /*function call*/ 
-                 << numElements+2 << TheCall->getNumArgs()
-                 << TheCall->getSourceRange());
-      return ExprError(Diag(TheCall->getLocEnd(),
-                            diag::err_typecheck_call_too_many_args)
-                 << 0 /*function call*/ 
-                 << numElements+2 << TheCall->getNumArgs()
-                 << TheCall->getSourceRange());
+    } else if (numElements != numResElements) {
+      QualType eltType = LHSType->getAs<VectorType>()->getElementType();
+      resType = Context.getVectorType(eltType, numResElements, false, false);
     }
   }
 
@@ -680,9 +688,11 @@ Action::OwningExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
         TheCall->getArg(i)->isValueDependent())
       continue;
 
-    llvm::APSInt Result;
-    if (SemaBuiltinConstantArg(TheCall, i, Result))
-      return ExprError();
+    llvm::APSInt Result(32);
+    if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
+      return ExprError(Diag(TheCall->getLocStart(),
+                  diag::err_shufflevector_nonconstant_argument)
+                << TheCall->getArg(i)->getSourceRange());
 
     if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
       return ExprError(Diag(TheCall->getLocStart(),
@@ -698,7 +708,7 @@ Action::OwningExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
   }
 
   return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(),
-                                            exprs.size(), exprs[0]->getType(),
+                                            exprs.size(), resType,
                                             TheCall->getCallee()->getLocStart(),
                                             TheCall->getRParenLoc()));
 }