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Fix an oops in x86 sibcall optimization. If the ByVal callee argument is itself passed as a pointer, then it's obviously not safe to do a tail call.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97797 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-03-05 08:38:04 +00:00
parent 2d4e4af45e
commit 4cae133780
2 changed files with 35 additions and 8 deletions
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22
lib/Target/X86/X86ISelLowering.cpp
View File

@ -2235,7 +2235,8 @@ static
bool MatchingStackOffset(SDValue Arg, unsigned Offset, ISD::ArgFlagsTy Flags,
MachineFrameInfo *MFI, const MachineRegisterInfo *MRI,
const X86InstrInfo *TII) {
int FI;
unsigned Bytes = Arg.getValueType().getSizeInBits() / 8;
int FI = INT_MAX;
if (Arg.getOpcode() == ISD::CopyFromReg) {
unsigned VR = cast<RegisterSDNode>(Arg.getOperand(1))->getReg();
if (!VR || TargetRegisterInfo::isPhysicalRegister(VR))
@ -2251,25 +2252,30 @@ bool MatchingStackOffset(SDValue Arg, unsigned Offset, ISD::ArgFlagsTy Flags,
if ((Opcode == X86::LEA32r || Opcode == X86::LEA64r) &&
Def->getOperand(1).isFI()) {
FI = Def->getOperand(1).getIndex();
if (MFI->getObjectSize(FI) != Flags.getByValSize())
return false;
Bytes = Flags.getByValSize();
} else
return false;
}
} else {
LoadSDNode *Ld = dyn_cast<LoadSDNode>(Arg);
if (!Ld)
} else if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Arg)) {
if (Flags.isByVal())
// ByVal argument is passed in as a pointer but it's now being
// derefernced. e.g.
// define @foo(%struct.X* %A) {
// tail call @bar(%struct.X* byval %A)
// }
return false;
SDValue Ptr = Ld->getBasePtr();
FrameIndexSDNode *FINode = dyn_cast<FrameIndexSDNode>(Ptr);
if (!FINode)
return false;
FI = FINode->getIndex();
}
} else
return false;
assert(FI != INT_MAX);
if (!MFI->isFixedObjectIndex(FI))
return false;
return Offset == MFI->getObjectOffset(FI);
return Offset == MFI->getObjectOffset(FI) && Bytes == MFI->getObjectSize(FI);
}
/// IsEligibleForTailCallOptimization - Check whether the call is eligible

21
test/CodeGen/X86/tailcall2.ll
View File

@ -195,3 +195,24 @@ bb2:
}
declare i32 @foo6(i32, i32, %struct.t* byval align 4)
; rdar://r7717598
%struct.ns = type { i32, i32 }
%struct.cp = type { float, float }
define %struct.ns* @t13(%struct.cp* %yy) nounwind ssp {
; 32: t13:
; 32-NOT: jmp
; 32: call
; 32: ret
; 64: t13:
; 64-NOT: jmp
; 64: call
; 64: ret
entry:
%0 = tail call fastcc %struct.ns* @foo7(%struct.cp* byval align 4 %yy, i8 signext 0) nounwind
ret %struct.ns* %0
}
declare fastcc %struct.ns* @foo7(%struct.cp* byval align 4, i8 signext) nounwind ssp