[mips] Allow tail-call optimization for vararg functions and functions which
use the caller's stack.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167048 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 862790b..47a4f1a 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -2660,8 +2660,9 @@
/// IsEligibleForTailCallOptimization - Check whether the call is eligible
/// for tail call optimization.
bool MipsTargetLowering::
-IsEligibleForTailCallOptimization(const MipsCC &MipsCCInfo, bool IsVarArg,
- unsigned NextStackOffset) const {
+IsEligibleForTailCallOptimization(const MipsCC &MipsCCInfo,
+ unsigned NextStackOffset,
+ const MipsFunctionInfo& FI) const {
if (!EnableMipsTailCalls)
return false;
@@ -2669,11 +2670,13 @@
if (Subtarget->inMips16Mode())
return false;
- if (MipsCCInfo.hasByValArg() || IsVarArg)
+ // Return false if either the callee or caller has a byval argument.
+ if (MipsCCInfo.hasByValArg() || FI.hasByvalArg())
return false;
- // Return true if no arguments are passed on stack.
- return MipsCCInfo.reservedArgArea() == NextStackOffset;
+ // Return true if the callee's next stack offset is no larger than the
+ // caller's.
+ return NextStackOffset <= FI.nextStackOffset();
}
SDValue
@@ -2725,13 +2728,12 @@
// Get a count of how many bytes are to be pushed on the stack.
unsigned NextStackOffset = CCInfo.getNextStackOffset();
- unsigned StackAlignment = TFL->getStackAlignment();
- NextStackOffset = RoundUpToAlignment(NextStackOffset, StackAlignment);
// Check if it's really possible to do a tail call.
if (isTailCall)
- isTailCall = IsEligibleForTailCallOptimization(MipsCCInfo, isVarArg,
- NextStackOffset);
+ isTailCall =
+ IsEligibleForTailCallOptimization(MipsCCInfo, NextStackOffset,
+ *MF.getInfo<MipsFunctionInfo>());
if (isTailCall)
++NumTailCalls;
@@ -2739,6 +2741,8 @@
// Chain is the output chain of the last Load/Store or CopyToReg node.
// ByValChain is the output chain of the last Memcpy node created for copying
// byval arguments to the stack.
+ unsigned StackAlignment = TFL->getStackAlignment();
+ NextStackOffset = RoundUpToAlignment(NextStackOffset, StackAlignment);
SDValue NextStackOffsetVal = DAG.getIntPtrConstant(NextStackOffset, true);
if (!isTailCall)
@@ -2765,6 +2769,8 @@
assert(Flags.getByValSize() &&
"ByVal args of size 0 should have been ignored by front-end.");
assert(ByValArg != MipsCCInfo.byval_end());
+ assert(!isTailCall &&
+ "Do not tail-call optimize if there is a byval argument.");
passByValArg(Chain, dl, RegsToPass, MemOpChains, StackPtr, MFI, DAG, Arg,
MipsCCInfo, *ByValArg, Flags, Subtarget->isLittle());
++ByValArg;
@@ -2817,10 +2823,8 @@
// emit ISD::STORE whichs stores the
// parameter value to a stack Location
- SDValue PtrOff = DAG.getNode(ISD::ADD, dl, getPointerTy(), StackPtr,
- DAG.getIntPtrConstant(VA.getLocMemOffset()));
- MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
- MachinePointerInfo(), false, false, 0));
+ MemOpChains.push_back(passArgOnStack(StackPtr, VA.getLocMemOffset(),
+ Chain, Arg, dl, isTailCall, DAG));
}
// Transform all store nodes into one single node because all store