Revisit my fix for PR9028: the issue is that DAGCombine was

generating i8 shift amounts for things like i1024 types.  Add
an assert in getNode to prevent this from occuring in the future,
fix the buggy transformation, revert my previous patch, and
document this gotcha in ISDOpcodes.h


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125465 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 3 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 696cd24f0a..09e33e2e62 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2434,7 +2434,6 @@ void SelectionDAGBuilder::visitShift(const User &I, unsigned Opcode) {
     DebugLoc DL = getCurDebugLoc();
     
     // If the operand is smaller than the shift count type, promote it.
-    MVT PtrTy = TLI.getPointerTy();
     if (ShiftSize > Op2Size)
       Op2 = DAG.getNode(ISD::ZERO_EXTEND, DL, ShiftTy, Op2);
     
@@ -2445,9 +2444,9 @@ void SelectionDAGBuilder::visitShift(const User &I, unsigned Opcode) {
     else if (ShiftSize >= Log2_32_Ceil(Op2.getValueType().getSizeInBits()))
       Op2 = DAG.getNode(ISD::TRUNCATE, DL, ShiftTy, Op2);
     // Otherwise we'll need to temporarily settle for some other convenient
-    // type.   Type legalization will make adjustments as needed.
+    // type.  Type legalization will make adjustments once the shiftee is split.
     else
-      Op2 = DAG.getZExtOrTrunc(Op2, DL, PtrTy);
+      Op2 = DAG.getZExtOrTrunc(Op2, DL, MVT::i32);
   }
 
   setValue(&I, DAG.getNode(Opcode, getCurDebugLoc(),