Leaf functions which do not save CSRs can be frameless even with -disable-fp-elim.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79039 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
index 309a5c6eb5dea7f5ddb50b0b7f294a07aa023d04..12fbb5dc03eafa47c86805c91b8cc0b876b8cb5d 100644 (file)
--- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp
@@ -440,6 +440,13 @@ bool ARMBaseRegisterInfo::hasFP(const MachineFunction &MF) const {
           MFI->isFrameAddressTaken());
 }
 
+bool ARMBaseRegisterInfo::hasStackFrame(const MachineFunction &MF) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  if (NoFramePointerElim && MFI->hasCalls())
+    return true;
+  return MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken();
+}
+
 /// estimateStackSize - Estimate and return the size of the frame.
 static unsigned estimateStackSize(MachineFunction &MF, MachineFrameInfo *MFI) {
   const MachineFrameInfo *FFI = MF.getFrameInfo();
@@ -589,7 +596,7 @@ ARMBaseRegisterInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
   }
 
   bool ExtraCSSpill = false;
-  if (!CanEliminateFrame || hasFP(MF)) {
+  if (!CanEliminateFrame || hasStackFrame(MF)) {
     AFI->setHasStackFrame(true);
 
     // If LR is not spilled, but at least one of R4, R5, R6, and R7 is spilled.

diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.h b/lib/Target/ARM/ARMBaseRegisterInfo.h
index 92dbb8435d524f9528237bd35dc5823d3ff61a27..c242489fdb84e3e01cabb9a51f8a6af83c458105 100644 (file)
--- a/lib/Target/ARM/ARMBaseRegisterInfo.h
+++ b/lib/Target/ARM/ARMBaseRegisterInfo.h
@@ -89,6 +89,8 @@ public:
 
   bool hasFP(const MachineFunction &MF) const;
 
+  bool hasStackFrame(const MachineFunction &MF) const;
+
   void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
                                             RegScavenger *RS = NULL) const;
 

diff --git a/test/CodeGen/Thumb2/frameless.ll b/test/CodeGen/Thumb2/frameless.ll
new file mode 100644 (file)
index 0000000..1b6bb62
--- /dev/null
+++ b/test/CodeGen/Thumb2/frameless.ll
@@ -0,0 +1,6 @@
+; RUN: llvm-as < %s | llc -mtriple=thumbv7-apple-darwin -disable-fp-elim | not grep mov
+; RUN: llvm-as < %s | llc -mtriple=thumbv7-linux -disable-fp-elim | not grep mov
+
+define arm_apcscc void @t() nounwind readnone {
+  ret void
+}