Revert r131664 and fix it in instcombine instead. rdar://9467055
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131708 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index e9a9963..2c90aa2 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1182,7 +1182,7 @@
bool IsStructRet = (Outs.empty()) ? false : Outs[0].Flags.isSRet();
bool IsSibCall = false;
// Temporarily disable tail calls so things don't break.
- if (!EnableARMTailCalls)
+ 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 c6f266b..0509d58 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -46,6 +46,7 @@
, PostRAScheduler(false)
, IsR9Reserved(ReserveR9)
, UseMovt(false)
+ , SupportsTailCall(false)
, HasFP16(false)
, HasD16(false)
, HasHardwareDivide(false)
@@ -153,6 +154,8 @@
else {
IsR9Reserved = ReserveR9 | (ARMArchVersion < V6);
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 0271c87..c149410 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -87,6 +87,11 @@
/// 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;
@@ -217,6 +222,7 @@
bool isR9Reserved() const { return IsR9Reserved; }
bool useMovt() const { return UseMovt && hasV6T2Ops(); }
+ bool supportsTailCall() const { return SupportsTailCall; }
bool allowsUnalignedMem() const { return AllowsUnalignedMem; }