Reenable tail calls for iOS 5.0 and later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141370 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index c352b46..6386c4d 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1222,8 +1222,8 @@
MachineFunction &MF = DAG.getMachineFunction();
bool IsStructRet = (Outs.empty()) ? false : Outs[0].Flags.isSRet();
bool IsSibCall = false;
- // Temporarily disable tail calls so things don't break.
- if (!EnableARMTailCalls)
+ // Disable tail calls if they're not supported.
+ if (!EnableARMTailCalls && !Subtarget->supportsTailCall())
isTailCall = false;
if (isTailCall) {
// Check if it's really possible to do a tail call.
diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index 82e5422..247d6be 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -60,6 +60,7 @@
, PostRAScheduler(false)
, IsR9Reserved(ReserveR9)
, UseMovt(false)
+ , SupportsTailCall(false)
, HasFP16(false)
, HasD16(false)
, HasHardwareDivide(false)
@@ -113,6 +114,8 @@
else {
IsR9Reserved = ReserveR9 | !HasV6Ops;
UseMovt = DarwinUseMOVT && hasV6T2Ops();
+ const Triple &T = getTargetTriple();
+ SupportsTailCall = T.getOS() == Triple::IOS && !T.isOSVersionLT(5, 0);
}
if (!isThumb() || hasThumb2())
diff --git a/lib/Target/ARM/ARMSubtarget.h b/lib/Target/ARM/ARMSubtarget.h
index 47e076a..b63e108 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -93,6 +93,11 @@
/// imms (including global addresses).
bool UseMovt;
+ /// SupportsTailCall - True if the OS supports tail call. The dynamic linker
+ /// must be able to synthesize call stubs for interworking between ARM and
+ /// Thumb.
+ bool SupportsTailCall;
+
/// HasFP16 - True if subtarget supports half-precision FP (We support VFP+HF
/// only so far)
bool HasFP16;
@@ -234,6 +239,7 @@
bool isR9Reserved() const { return IsR9Reserved; }
bool useMovt() const { return UseMovt && hasV6T2Ops(); }
+ bool supportsTailCall() const { return SupportsTailCall; }
bool allowsUnalignedMem() const { return AllowsUnalignedMem; }
diff --git a/test/CodeGen/ARM/call-tc.ll b/test/CodeGen/ARM/call-tc.ll
index e01750b..f78d998 100644
--- a/test/CodeGen/ARM/call-tc.ll
+++ b/test/CodeGen/ARM/call-tc.ll
@@ -1,6 +1,10 @@
; RUN: llc < %s -mtriple=armv6-apple-darwin -mattr=+vfp2 -arm-tail-calls | FileCheck %s -check-prefix=CHECKV6
; RUN: llc < %s -mtriple=armv6-linux-gnueabi -relocation-model=pic -mattr=+vfp2 -arm-tail-calls | FileCheck %s -check-prefix=CHECKELF
; RUN: llc < %s -mtriple=thumbv7-apple-darwin -arm-tail-calls | FileCheck %s -check-prefix=CHECKT2D
+; RUN: llc < %s -mtriple=thumbv7-apple-ios5.0 | FileCheck %s -check-prefix=CHECKT2D
+
+; Enable tailcall optimization for iOS 5.0
+; rdar://9120031
@t = weak global i32 ()* null ; <i32 ()**> [#uses=1]
