From 0110ac66ebd1e59e6ac163e13670f36d091084f6 Mon Sep 17 00:00:00 2001
From: Evan Cheng <evan.cheng@apple.com>
Date: Sat, 19 Jun 2010 01:01:32 +0000
Subject: [PATCH] Disable sibcall optimization for Thumb1 for now since
 Thumb1RegisterInfo::emitEpilogue is not expecting them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106368 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMISelLowering.cpp            | 25 +++++++++++++------
 test/CodeGen/ARM/call-tc.ll                   | 11 +++++---
 test/CodeGen/Thumb/2010-06-18-SibCallCrash.ll |  8 ++++++
 test/CodeGen/Thumb2/thumb2-call-tc.ll         |  2 +-
 4 files changed, 33 insertions(+), 13 deletions(-)
 create mode 100644 test/CodeGen/Thumb/2010-06-18-SibCallCrash.ll

diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 3dfd080c0af..d0c40229d40 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -1389,7 +1389,6 @@ ARMTargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
                                     const SmallVectorImpl<ISD::OutputArg> &Outs,
                                     const SmallVectorImpl<ISD::InputArg> &Ins,
                                                      SelectionDAG& DAG) const {
-
   const Function *CallerF = DAG.getMachineFunction().getFunction();
   CallingConv::ID CallerCC = CallerF->getCallingConv();
   bool CCMatch = CallerCC == CalleeCC;
@@ -1407,19 +1406,29 @@ ARMTargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
   if (isCalleeStructRet || isCallerStructRet)
     return false;
 
-  // On Thumb, for the moment, we can only do this to functions defined in this
-  // compilation, or to indirect calls.  A Thumb B to an ARM function is not
-  // easily fixed up in the linker, unlike BL.
-  if (Subtarget->isThumb()) {
-    if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+  // FIXME: Completely disable sibcal for Thumb1 since Thumb1RegisterInfo::
+  // emitEpilogue is not ready for them.
+  if (Subtarget->isThumb1Only())
+    return false;
+
+  if (isa<ExternalSymbolSDNode>(Callee))
+      return false;
+
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+    if (Subtarget->isThumb1Only())
+      return false;
+
+    // On Thumb, for the moment, we can only do this to functions defined in this
+    // compilation, or to indirect calls.  A Thumb B to an ARM function is not
+    // easily fixed up in the linker, unlike BL.
+    if (Subtarget->isThumb()) {
       const GlobalValue *GV = G->getGlobal();
       if (GV->isDeclaration() || GV->isWeakForLinker())
         return false;
-    } else if (isa<ExternalSymbolSDNode>(Callee)) {
-      return false;
     }
   }
 
+
   // If the calling conventions do not match, then we'd better make sure the
   // results are returned in the same way as what the caller expects.
   if (!CCMatch) {
diff --git a/test/CodeGen/ARM/call-tc.ll b/test/CodeGen/ARM/call-tc.ll
index 8103fab2092..2bbdb91c90b 100644
--- a/test/CodeGen/ARM/call-tc.ll
+++ b/test/CodeGen/ARM/call-tc.ll
@@ -7,22 +7,25 @@
 
 declare void @g(i32, i32, i32, i32)
 
-define void @f() {
+define void @t1() {
+; CHECKELF: t1:
 ; CHECKELF: PLT
         call void @g( i32 1, i32 2, i32 3, i32 4 )
         ret void
 }
 
-define void @g.upgrd.1() {
+define void @t2() {
+; CHECKV4: t2:
 ; CHECKV4: bx r0 @ TAILCALL
+; CHECKV5: t2:
 ; CHECKV5: bx r0 @ TAILCALL
         %tmp = load i32 ()** @t         ; <i32 ()*> [#uses=1]
         %tmp.upgrd.2 = tail call i32 %tmp( )            ; <i32> [#uses=0]
         ret void
 }
 
-define i32* @m_231b(i32, i32, i32*, i32*, i32*) nounwind {
-; CHECKV4: m_231b
+define i32* @t3(i32, i32, i32*, i32*, i32*) nounwind {
+; CHECKV4: t3:
 ; CHECKV4: bx r{{.*}}
 BB0:
   %5 = inttoptr i32 %0 to i32*                    ; <i32*> [#uses=1]
diff --git a/test/CodeGen/Thumb/2010-06-18-SibCallCrash.ll b/test/CodeGen/Thumb/2010-06-18-SibCallCrash.ll
new file mode 100644
index 00000000000..ad8b064bf4b
--- /dev/null
+++ b/test/CodeGen/Thumb/2010-06-18-SibCallCrash.ll
@@ -0,0 +1,8 @@
+; RUN: llc -march=thumb < %s
+; rdar://8104457
+
+define arm_apcscc void @t(i32* %m) nounwind {
+entry:
+  tail call arm_apcscc  void undef(i32* %m, i16 zeroext undef) nounwind
+  ret void
+}
diff --git a/test/CodeGen/Thumb2/thumb2-call-tc.ll b/test/CodeGen/Thumb2/thumb2-call-tc.ll
index d31ae0cc455..fe47e348ab2 100644
--- a/test/CodeGen/Thumb2/thumb2-call-tc.ll
+++ b/test/CodeGen/Thumb2/thumb2-call-tc.ll
@@ -11,7 +11,7 @@ define void @f() {
 
 ; LINUX: f:
 ; LINUX: bl g
-        call void @g( i32 1, i32 2, i32 3, i32 4 )
+        tail call void @g( i32 1, i32 2, i32 3, i32 4 )
         ret void
 }