[mips] Do not tail-call optimize vararg functions or functions with byval
arguments.
This is rather conservative and should be fixed later to be more aggressive.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166851 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 02674f5..94e1868 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -2639,19 +2639,16 @@
/// IsEligibleForTailCallOptimization - Check whether the call is eligible
/// for tail call optimization.
bool MipsTargetLowering::
-IsEligibleForTailCallOptimization(CallingConv::ID CalleeCC,
+IsEligibleForTailCallOptimization(const MipsCC &MipsCCInfo, bool IsVarArg,
unsigned NextStackOffset) const {
if (!EnableMipsTailCalls)
return false;
- // Do not tail-call optimize if there is an argument passed on stack.
- if (IsO32 && (CalleeCC != CallingConv::Fast)) {
- if (NextStackOffset > 16)
- return false;
- } else if (NextStackOffset)
+ if (MipsCCInfo.hasByValArg() || IsVarArg)
return false;
- return true;
+ // Return true if no arguments are passed on stack.
+ return MipsCCInfo.reservedArgArea() == NextStackOffset;
}
/// LowerCall - functions arguments are copied from virtual regs to
@@ -2690,7 +2687,8 @@
// Check if it's really possible to do a tail call.
if (isTailCall)
- isTailCall = IsEligibleForTailCallOptimization(CallConv, NextStackOffset);
+ isTailCall = IsEligibleForTailCallOptimization(MipsCCInfo, isVarArg,
+ NextStackOffset);
if (isTailCall)
++NumTailCalls;