Re-enable SelectionDAG CSE for calls. It matters in the case of

libcalls, as in this testcase on ARM.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56226 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2008-09-15 19:46:03 +00:00
parent f19063b33f
commit 5eb0cecbc5
3 changed files with 52 additions and 7 deletions

View File

@ -2205,7 +2205,8 @@ public:
/// Set this call to not be marked as a tail call. Normally setter
/// methods in SDNodes are unsafe because it breaks the CSE map,
/// but we don't CSE calls so it's ok in this case.
/// but we don't include the tail call flag for calls so it's ok
/// in this case.
void setNotTailCall() { IsTailCall = false; }
SDValue getChain() const { return getOperand(0); }

View File

@ -423,6 +423,12 @@ static void AddNodeIDNode(FoldingSetNodeID &ID, const SDNode *N) {
ID.AddPointer(CP->getConstVal());
break;
}
case ISD::CALL: {
const CallSDNode *Call = cast<CallSDNode>(N);
ID.AddInteger(Call->getCallingConv());
ID.AddInteger(Call->isVarArg());
break;
}
case ISD::LOAD: {
const LoadSDNode *LD = cast<LoadSDNode>(N);
ID.AddInteger(LD->getAddressingMode());
@ -636,7 +642,6 @@ bool SelectionDAG::RemoveNodeFromCSEMaps(SDNode *N) {
// not subject to CSE.
if (!Erased && N->getValueType(N->getNumValues()-1) != MVT::Flag &&
!N->isMachineOpcode() &&
N->getOpcode() != ISD::CALL &&
N->getOpcode() != ISD::DBG_LABEL &&
N->getOpcode() != ISD::DBG_STOPPOINT &&
N->getOpcode() != ISD::EH_LABEL &&
@ -662,7 +667,6 @@ SDNode *SelectionDAG::AddNonLeafNodeToCSEMaps(SDNode *N) {
switch (N->getOpcode()) {
default: break;
case ISD::CALL:
case ISD::HANDLENODE:
case ISD::DBG_LABEL:
case ISD::DBG_STOPPOINT:
@ -3310,13 +3314,23 @@ SDValue
SelectionDAG::getCall(unsigned CallingConv, bool IsVarArgs, bool IsTailCall,
SDVTList VTs,
const SDValue *Operands, unsigned NumOperands) {
// Do not CSE calls. Note that in addition to being a compile-time
// optimization (since attempting CSE of calls is unlikely to be
// meaningful), we actually depend on this behavior. CallSDNode can
// be mutated, which is only safe if calls are not CSE'd.
// Do not include isTailCall in the folding set profile.
FoldingSetNodeID ID;
AddNodeIDNode(ID, ISD::CALL, VTs, Operands, NumOperands);
ID.AddInteger(CallingConv);
ID.AddInteger(IsVarArgs);
void *IP = 0;
if (SDNode *E = CSEMap.FindNodeOrInsertPos(ID, IP)) {
// Instead of including isTailCall in the folding set, we just
// set the flag of the existing node.
if (!IsTailCall)
cast<CallSDNode>(E)->setNotTailCall();
return SDValue(E, 0);
}
SDNode *N = NodeAllocator.Allocate<CallSDNode>();
new (N) CallSDNode(CallingConv, IsVarArgs, IsTailCall,
VTs, Operands, NumOperands);
CSEMap.InsertNode(N, IP);
AllNodes.push_back(N);
return SDValue(N, 0);
}

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@ -0,0 +1,30 @@
; RUN: llvm-as < %s | llc -march=arm | grep {bl.\*__ltdf} | count 1
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
target triple = "i386-apple-darwin8"
; Without CSE of libcalls, there are two calls in the output instead of one.
define i32 @u_f_nonbon(double %lambda) nounwind {
entry:
%tmp19.i.i = load double* null, align 4 ; <double> [#uses=2]
%tmp6.i = fcmp olt double %tmp19.i.i, 1.000000e+00 ; <i1> [#uses=1]
%dielectric.0.i = select i1 %tmp6.i, double 1.000000e+00, double %tmp19.i.i ; <double> [#uses=1]
%tmp10.i4 = fdiv double 0x4074C2D71F36262D, %dielectric.0.i ; <double> [#uses=1]
br i1 false, label %bb28.i, label %bb508.i
bb28.i: ; preds = %bb28.i, %entry
br i1 false, label %bb502.loopexit.i, label %bb28.i
bb.nph53.i: ; preds = %bb502.loopexit.i
%tmp354.i = sub double -0.000000e+00, %tmp10.i4 ; <double> [#uses=0]
br label %bb244.i
bb244.i: ; preds = %bb244.i, %bb.nph53.i
br label %bb244.i
bb502.loopexit.i: ; preds = %bb28.i
br i1 false, label %bb.nph53.i, label %bb508.i
bb508.i: ; preds = %bb502.loopexit.i, %entry
ret i32 1
}