[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
This commit is contained in:
Chuang-Yu Cheng 2016-08-17 03:17:44 +00:00
parent 6ed8da0049
commit f7ba716bcb
2 changed files with 20 additions and 1 deletions

View File

@ -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))

View File

@ -189,3 +189,15 @@ define void @w_caller(i8* %ptr) {
; CHECK-SCO-LABEL: w_caller:
; CHECK-SCO: bl w_callee
}
%struct.byvalTest = type { [8 x i8] }
@byval = common global %struct.byvalTest zeroinitializer
define void @byval_callee(%struct.byvalTest* byval %ptr) { ret void }
define void @byval_caller() {
tail call void @byval_callee(%struct.byvalTest* byval @byval)
ret void
; CHECK-SCO-LABEL: bl byval_callee
; CHECK-SCO: bl byval_callee
}