[ppc64] Don't apply sibling call optimization if callee has any byval arg

This is a quick work around, because in some cases, e.g. caller's stack
size > callee's stack size, we are still able to apply sibling call
optimization even callee has any byval arg.

This patch fix: https://llvm.org/bugs/show_bug.cgi?id=28328

Reviewers: hfinkel kbarton nemanjai amehsan
Subscribers: hans, tjablin

https://reviews.llvm.org/D23441

llvm-svn: 278900

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index e2cc9212597..7dfff5b83a7 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -4049,10 +4049,17 @@ PPCTargetLowering::IsEligibleForTailCallOptimization_64SVR4(
   if (CalleeCC != CallingConv::Fast && CalleeCC != CallingConv::C)
     return false;
 
-  // Functions containing by val parameters are not supported.
+  // Caller contains any byval parameter is not supported.
   if (any_of(Ins, [](const ISD::InputArg &IA) { return IA.Flags.isByVal(); }))
     return false;
 
+  // Callee contains any byval parameter is not supported, too.
+  // Note: This is a quick work around, because in some cases, e.g.
+  // caller's stack size > callee's stack size, we are still able to apply
+  // sibling call optimization. See: https://reviews.llvm.org/D23441#513574
+  if (any_of(Outs, [](const ISD::OutputArg& OA) { return OA.Flags.isByVal(); }))
+    return false;
+
   // No TCO/SCO on indirect call because Caller have to restore its TOC
   if (!isFunctionGlobalAddress(Callee) &&
       !isa<ExternalSymbolSDNode>(Callee))