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/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 7240fb9..1dbbf4f 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -240,7 +240,13 @@
/// FindBetterChain - Walk up chain skipping non-aliasing memory nodes,
/// looking for a better chain (aliasing node.)
SDValue FindBetterChain(SDNode *N, SDValue Chain);
-
+
+ /// getShiftAmountTy - Returns a type large enough to hold any valid
+ /// shift amount - before type legalization these can be huge.
+ MVT getShiftAmountTy() {
+ return LegalTypes ? TLI.getShiftAmountTy() : TLI.getPointerTy();
+ }
+
public:
DAGCombiner(SelectionDAG &D, AliasAnalysis &A, bool fast)
: DAG(D),
@@ -1301,7 +1307,7 @@
if (N1C && N1C->getAPIntValue().isPowerOf2())
return DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
DAG.getConstant(N1C->getAPIntValue().logBase2(),
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
// fold (mul x, -(1 << c)) -> -(x << c) or (-x) << c
if (N1C && isPowerOf2_64(-N1C->getSExtValue()))
// FIXME: If the input is something that is easily negated (e.g. a
@@ -1310,7 +1316,7 @@
DAG.getConstant(0, VT),
DAG.getNode(ISD::SHL, N->getDebugLoc(), VT, N0,
DAG.getConstant(Log2_64(-N1C->getSExtValue()),
- TLI.getShiftAmountTy())));
+ getShiftAmountTy())));
// (mul (shl X, c1), c2) -> (mul X, c2 << c1)
if (N1C && N0.getOpcode() == ISD::SHL &&
isa<ConstantSDNode>(N0.getOperand(1))) {
@@ -1406,18 +1412,18 @@
// Splat the sign bit into the register
SDValue SGN = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, N0,
DAG.getConstant(VT.getSizeInBits()-1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
AddToWorkList(SGN.getNode());
// Add (N0 < 0) ? abs2 - 1 : 0;
SDValue SRL = DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, SGN,
DAG.getConstant(VT.getSizeInBits() - lg2,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
SDValue ADD = DAG.getNode(ISD::ADD, N->getDebugLoc(), VT, N0, SRL);
AddToWorkList(SRL.getNode());
AddToWorkList(ADD.getNode()); // Divide by pow2
SDValue SRA = DAG.getNode(ISD::SRA, N->getDebugLoc(), VT, ADD,
- DAG.getConstant(lg2, TLI.getShiftAmountTy()));
+ DAG.getConstant(lg2, getShiftAmountTy()));
// If we're dividing by a positive value, we're done. Otherwise, we must
// negate the result.
@@ -1467,7 +1473,7 @@
if (N1C && N1C->getAPIntValue().isPowerOf2())
return DAG.getNode(ISD::SRL, N->getDebugLoc(), VT, N0,
DAG.getConstant(N1C->getAPIntValue().logBase2(),
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
// fold (udiv x, (shl c, y)) -> x >>u (log2(c)+y) iff c is power of 2
if (N1.getOpcode() == ISD::SHL) {
if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
@@ -1607,7 +1613,7 @@
if (N1C && N1C->getAPIntValue() == 1)
return DAG.getNode(ISD::SRA, N->getDebugLoc(), N0.getValueType(), N0,
DAG.getConstant(N0.getValueType().getSizeInBits() - 1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
// fold (mulhs x, undef) -> 0
if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, VT);
@@ -2613,7 +2619,7 @@
TLI.isOperationLegalOrCustom(ISD::TRUNCATE, VT) &&
TLI.isTruncateFree(VT, TruncVT)) {
- SDValue Amt = DAG.getConstant(ShiftAmt, TLI.getShiftAmountTy());
+ SDValue Amt = DAG.getConstant(ShiftAmt, getShiftAmountTy());
SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT,
N0.getOperand(0), Amt);
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, N0.getDebugLoc(), TruncVT,
@@ -2740,7 +2746,7 @@
if (ShAmt) {
Op = DAG.getNode(ISD::SRL, N0.getDebugLoc(), VT, Op,
- DAG.getConstant(ShAmt, TLI.getShiftAmountTy()));
+ DAG.getConstant(ShAmt, getShiftAmountTy()));
AddToWorkList(Op.getNode());
}
@@ -5722,7 +5728,7 @@
if (N2C && ((N2C->getAPIntValue() & (N2C->getAPIntValue()-1)) == 0)) {
unsigned ShCtV = N2C->getAPIntValue().logBase2();
ShCtV = XType.getSizeInBits()-ShCtV-1;
- SDValue ShCt = DAG.getConstant(ShCtV, TLI.getShiftAmountTy());
+ SDValue ShCt = DAG.getConstant(ShCtV, getShiftAmountTy());
SDValue Shift = DAG.getNode(ISD::SRL, N0.getDebugLoc(),
XType, N0, ShCt);
AddToWorkList(Shift.getNode());
@@ -5738,7 +5744,7 @@
SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(),
XType, N0,
DAG.getConstant(XType.getSizeInBits()-1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
AddToWorkList(Shift.getNode());
if (XType.bitsGT(AType)) {
@@ -5787,7 +5793,7 @@
// shl setcc result by log2 n2c
return DAG.getNode(ISD::SHL, DL, N2.getValueType(), Temp,
DAG.getConstant(N2C->getAPIntValue().logBase2(),
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
}
// Check to see if this is the equivalent of setcc
@@ -5810,7 +5816,7 @@
SDValue Ctlz = DAG.getNode(ISD::CTLZ, N0.getDebugLoc(), XType, N0);
return DAG.getNode(ISD::SRL, DL, XType, Ctlz,
DAG.getConstant(Log2_32(XType.getSizeInBits()),
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
}
// fold (setgt X, 0) -> (srl (and (-X, ~X), size(X)-1))
if (N1C && N1C->isNullValue() && CC == ISD::SETGT) {
@@ -5820,13 +5826,13 @@
return DAG.getNode(ISD::SRL, DL, XType,
DAG.getNode(ISD::AND, XType, NegN0, NotN0),
DAG.getConstant(XType.getSizeInBits()-1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
}
// fold (setgt X, -1) -> (xor (srl (X, size(X)-1), 1))
if (N1C && N1C->isAllOnesValue() && CC == ISD::SETGT) {
SDValue Sign = DAG.getNode(ISD::SRL, N0.getDebugLoc(), XType, N0,
DAG.getConstant(XType.getSizeInBits()-1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
return DAG.getNode(ISD::XOR, DL, XType, Sign, DAG.getConstant(1, XType));
}
}
@@ -5839,7 +5845,7 @@
MVT XType = N0.getValueType();
SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType, N0,
DAG.getConstant(XType.getSizeInBits()-1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(), XType,
N0, Shift);
AddToWorkList(Shift.getNode());
@@ -5856,7 +5862,7 @@
SDValue Shift = DAG.getNode(ISD::SRA, N0.getDebugLoc(), XType,
N0,
DAG.getConstant(XType.getSizeInBits()-1,
- TLI.getShiftAmountTy()));
+ getShiftAmountTy()));
SDValue Add = DAG.getNode(ISD::ADD, N0.getDebugLoc(),
XType, N0, Shift);
AddToWorkList(Shift.getNode());