Fix PR3401: when using large integers, the type
returned by getShiftAmountTy may be too small
to hold shift values (it is an i8 on x86-32).
Before and during type legalization, use a large
but legal type for shift amounts: getPointerTy;
afterwards use getShiftAmountTy, fixing up any
shift amounts with a big type during operation
legalization. Thanks to Dan for writing the
original patch (which I shamelessly pillaged).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63482 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index f5287b0..1b0d61c 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1287,6 +1287,17 @@
return SDValue(N, 0);
}
+/// getShiftAmountOperand - Return the specified value casted to
+/// the target's desired shift amount type.
+SDValue SelectionDAG::getShiftAmountOperand(SDValue Op) {
+ MVT OpTy = Op.getValueType();
+ MVT ShTy = TLI.getShiftAmountTy();
+ if (OpTy == ShTy || OpTy.isVector()) return Op;
+
+ ISD::NodeType Opcode = OpTy.bitsGT(ShTy) ? ISD::TRUNCATE : ISD::ZERO_EXTEND;
+ return getNode(Opcode, ShTy, Op);
+}
+
/// CreateStackTemporary - Create a stack temporary, suitable for holding the
/// specified value type.
SDValue SelectionDAG::CreateStackTemporary(MVT VT, unsigned minAlign) {
@@ -2529,9 +2540,6 @@
"Shift operators return type must be the same as their first arg");
assert(VT.isInteger() && N2.getValueType().isInteger() &&
"Shifts only work on integers");
- assert((N2.getValueType() == TLI.getShiftAmountTy() ||
- (N2.getValueType().isVector() && N2.getValueType().isInteger())) &&
- "Wrong type for shift amount");
// Always fold shifts of i1 values so the code generator doesn't need to
// handle them. Since we know the size of the shift has to be less than the