Fix invalid shufflevector operands

This patch fixes bug 23800 ( https://llvm.org/bugs/show_bug.cgi?id=23800#c2 ). There existed a case where the index operand from extractelement was directly used to create a shufflevector mask. Since the index can be of any integral type but the mask must only contain 32 bit integers a 64 bit index operand led to an assertion error later on.

Committed on behalf of mpflanzer (Moritz Pflanzer)

Differential Revision: http://reviews.llvm.org/D10838

llvm-svn: 243851

1 files changed, 12 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index f3e48362130..195c7a4678f 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1162,6 +1162,16 @@ static llvm::Constant *getMaskElt(llvm::ShuffleVectorInst *SVI, unsigned Idx,
   return llvm::ConstantInt::get(I32Ty, Off+MV);
 }
 
+static llvm::Constant *getAsInt32(llvm::ConstantInt *C, llvm::Type *I32Ty) {
+  if (C->getBitWidth() != 32) {
+      assert(llvm::ConstantInt::isValueValidForType(I32Ty,
+                                                    C->getZExtValue()) &&
+             "Index operand too large for shufflevector mask!");
+      return llvm::ConstantInt::get(I32Ty, C->getZExtValue());
+  }
+  return C;
+}
+
 Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
   bool Ignore = TestAndClearIgnoreResultAssign();
   (void)Ignore;
@@ -1212,7 +1222,8 @@ Value *ScalarExprEmitter::VisitInitListExpr(InitListExpr *E) {
           Value *LHS = nullptr, *RHS = nullptr;
           if (CurIdx == 0) {
             // insert into undef -> shuffle (src, undef)
-            Args.push_back(C);
+            // shufflemask must use an i32
+            Args.push_back(getAsInt32(C, CGF.Int32Ty));
             Args.resize(ResElts, llvm::UndefValue::get(CGF.Int32Ty));
 
             LHS = EI->getVectorOperand();