Enable tail call optimization for functions that return a struct (bug 3664) and for functions that return types that need extending (e.g i1).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67934 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer 2009-03-28 08:33:27 +00:00
parent 1717f3af08
commit e75fd69f15
4 changed files with 37 additions and 12 deletions

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@ -1206,18 +1206,7 @@ public:
/// preceeds the RET node and whether the return uses the result of the node
/// or is a void return. This function can be used by the target to determine
/// eligiblity of tail call optimization.
static bool CheckTailCallReturnConstraints(CallSDNode *TheCall, SDValue Ret) {
unsigned NumOps = Ret.getNumOperands();
if ((NumOps == 1 &&
(Ret.getOperand(0) == SDValue(TheCall,1) ||
Ret.getOperand(0) == SDValue(TheCall,0))) ||
(NumOps > 1 &&
Ret.getOperand(0) == SDValue(TheCall,
TheCall->getNumValues()-1) &&
Ret.getOperand(1) == SDValue(TheCall,0)))
return true;
return false;
}
static bool CheckTailCallReturnConstraints(CallSDNode *TheCall, SDValue Ret);
/// GetPossiblePreceedingTailCall - Get preceeding TailCallNodeOpCode node if
/// it exists. Skip a possible ISD::TokenFactor.

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@ -2571,3 +2571,27 @@ SDValue TargetLowering::BuildUDIV(SDNode *N, SelectionDAG &DAG,
DAG.getConstant(magics.s-1, getShiftAmountTy()));
}
}
bool TargetLowering::CheckTailCallReturnConstraints(CallSDNode *TheCall, SDValue Ret) {
unsigned NumOps = Ret.getNumOperands();
// Struct return.
if(NumOps >= 5&&
Ret.getOperand(1).getOpcode()==ISD::MERGE_VALUES &&
Ret.getOperand(1).getOperand(0) == SDValue(TheCall, 0))
return true;
if ((NumOps == 1 &&
(Ret.getOperand(0) == SDValue(TheCall,1) ||
Ret.getOperand(0) == SDValue(TheCall,0))) ||
(NumOps == 3 &&
Ret.getOperand(1).getOpcode() == ISD::ANY_EXTEND &&
Ret.getOperand(1).getNumOperands()>0 &&
Ret.getOperand(1).getOperand(0).getOpcode() == ISD::TRUNCATE &&
Ret.getOperand(1).getOperand(0).getNumOperands()>0 &&
Ret.getOperand(1).getOperand(0).getOperand(0) == SDValue(TheCall, 0)) ||
(NumOps > 1 &&
Ret.getOperand(0) == SDValue(TheCall,
TheCall->getNumValues()-1) &&
Ret.getOperand(1) == SDValue(TheCall,0)))
return true;
return false;
}

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@ -0,0 +1,6 @@
; RUN: llvm-as < %s | llc -march=x86 -tailcallopt | grep TAILCALL
define fastcc i1 @i1test(i32, i32, i32, i32) {
entry:
%4 = tail call fastcc i1 @i1test( i32 %0, i32 %1, i32 %2, i32 %3)
ret i1 %4
}

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@ -0,0 +1,6 @@
; RUN: llvm-as < %s | llc -march=x86 -tailcallopt | grep TAILCALL
define fastcc { { i8*, i8* }*, i8*} @init({ { i8*, i8* }*, i8*}, i32) {
entry:
%2 = tail call fastcc { { i8*, i8* }*, i8* } @init({ { i8*, i8*}*, i8*} %0, i32 %1)
ret { { i8*, i8* }*, i8*} %2
}