Move 3 "(add (select cc, 0, c), x) -> (select cc, x, (add, x, c))"
related transformations out of target-specific dag combine into the
ARM backend. These were added by Evan in r37685 with no testcases
and only seems to help ARM (e.g. test/CodeGen/ARM/select_xform.ll).
Add some simple X86-specific (for now) DAG combines that turn things
like cond ? 8 : 0 -> (zext(cond) << 3). This happens frequently
with the recently added cp constant select optimization, but is a
very general xform. For example, we now compile the second example
in const-select.ll to:
_test:
movsd LCPI2_0, %xmm0
ucomisd 8(%esp), %xmm0
seta %al
movzbl %al, %eax
movl 4(%esp), %ecx
movsbl (%ecx,%eax,4), %eax
ret
instead of:
_test:
movl 4(%esp), %eax
leal 4(%eax), %ecx
movsd LCPI2_0, %xmm0
ucomisd 8(%esp), %xmm0
cmovbe %eax, %ecx
movsbl (%ecx), %eax
ret
This passes multisource and dejagnu.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66779 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 993092e..671c85e 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -543,8 +543,10 @@
if (AddTo) {
// Push the new nodes and any users onto the worklist
for (unsigned i = 0, e = NumTo; i != e; ++i) {
- AddToWorkList(To[i].getNode());
- AddUsersToWorkList(To[i].getNode());
+ if (To[i].getNode()) {
+ AddToWorkList(To[i].getNode());
+ AddUsersToWorkList(To[i].getNode());
+ }
}
}
@@ -944,65 +946,6 @@
return SDValue();
}
-static
-SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp,
- SelectionDAG &DAG, const TargetLowering &TLI,
- bool LegalOperations) {
- MVT VT = N->getValueType(0);
- unsigned Opc = N->getOpcode();
- bool isSlctCC = Slct.getOpcode() == ISD::SELECT_CC;
- SDValue LHS = isSlctCC ? Slct.getOperand(2) : Slct.getOperand(1);
- SDValue RHS = isSlctCC ? Slct.getOperand(3) : Slct.getOperand(2);
- ISD::CondCode CC = ISD::SETCC_INVALID;
-
- if (isSlctCC) {
- CC = cast<CondCodeSDNode>(Slct.getOperand(4))->get();
- } else {
- SDValue CCOp = Slct.getOperand(0);
- if (CCOp.getOpcode() == ISD::SETCC)
- CC = cast<CondCodeSDNode>(CCOp.getOperand(2))->get();
- }
-
- bool DoXform = false;
- bool InvCC = false;
- assert ((Opc == ISD::ADD || (Opc == ISD::SUB && Slct == N->getOperand(1))) &&
- "Bad input!");
-
- if (LHS.getOpcode() == ISD::Constant &&
- cast<ConstantSDNode>(LHS)->isNullValue()) {
- DoXform = true;
- } else if (CC != ISD::SETCC_INVALID &&
- RHS.getOpcode() == ISD::Constant &&
- cast<ConstantSDNode>(RHS)->isNullValue()) {
- std::swap(LHS, RHS);
- SDValue Op0 = Slct.getOperand(0);
- MVT OpVT = isSlctCC ? Op0.getValueType() :
- Op0.getOperand(0).getValueType();
- bool isInt = OpVT.isInteger();
- CC = ISD::getSetCCInverse(CC, isInt);
-
- if (LegalOperations && !TLI.isCondCodeLegal(CC, OpVT))
- return SDValue(); // Inverse operator isn't legal.
-
- DoXform = true;
- InvCC = true;
- }
-
- if (DoXform) {
- SDValue Result = DAG.getNode(Opc, RHS.getDebugLoc(), VT, OtherOp, RHS);
- if (isSlctCC)
- return DAG.getSelectCC(N->getDebugLoc(), OtherOp, Result,
- Slct.getOperand(0), Slct.getOperand(1), CC);
- SDValue CCOp = Slct.getOperand(0);
- if (InvCC)
- CCOp = DAG.getSetCC(Slct.getDebugLoc(), CCOp.getValueType(),
- CCOp.getOperand(0), CCOp.getOperand(1), CC);
- return DAG.getNode(ISD::SELECT, N->getDebugLoc(), VT,
- CCOp, OtherOp, Result);
- }
- return SDValue();
-}
-
SDValue DAGCombiner::visitADD(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
@@ -1123,16 +1066,6 @@
if (Result.getNode()) return Result;
}
- // fold (add (select cc, 0, c), x) -> (select cc, x, (add, x, c))
- if (N0.getOpcode() == ISD::SELECT && N0.getNode()->hasOneUse()) {
- SDValue Result = combineSelectAndUse(N, N0, N1, DAG, TLI, LegalOperations);
- if (Result.getNode()) return Result;
- }
- if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
- SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations);
- if (Result.getNode()) return Result;
- }
-
return SDValue();
}
@@ -1246,11 +1179,6 @@
N0.getOperand(1).getOperand(1) == N1)
return DAG.getNode(ISD::SUB, N->getDebugLoc(), VT,
N0.getOperand(0), N0.getOperand(1).getOperand(0));
- // fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c))
- if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
- SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, LegalOperations);
- if (Result.getNode()) return Result;
- }
// If either operand of a sub is undef, the result is undef
if (N0.getOpcode() == ISD::UNDEF)