1 files changed, 9 insertions, 2 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index fa3fedf987c..426fb347af6 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -18,6 +18,7 @@
 #include "llvm/CodeGen/CallingConvLower.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetOptions.h"
 
 namespace llvm {
@@ -664,8 +665,14 @@ namespace llvm {
     void markLibCallAttributes(MachineFunction *MF, unsigned CC,
                                ArgListTy &Args) const override;
 
-    MVT getScalarShiftAmountTy(const DataLayout &, EVT) const override {
-      return MVT::i8;
+    // For i512, DAGTypeLegalizer::SplitInteger needs a shift amount 256,
+    // which cannot be held by i8, therefore use i16 instead. In all the
+    // other situations i8 is sufficient.
+    MVT getScalarShiftAmountTy(const DataLayout &, EVT VT) const override {
+      MVT T = VT.getSizeInBits() >= 512 ? MVT::i16 : MVT::i8;
+      assert((VT.getSizeInBits() + 1) / 2 < (1U << T.getSizeInBits()) &&
+             "Scalar shift amount type too small");
+      return T;
     }
 
     const MCExpr *