Even if we don't have 7 bytes of stack space we may need to save and
restore the stack pointer from the frame pointer on thumbv6.
Fixes rdar://8819685
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123196 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/Thumb1FrameLowering.cpp b/lib/Target/ARM/Thumb1FrameLowering.cpp
index e3f2d2d..8a6dda8 100644
--- a/lib/Target/ARM/Thumb1FrameLowering.cpp
+++ b/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -156,6 +156,12 @@
// to reference locals.
if (RegInfo->hasBasePointer(MF))
BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), BasePtr).addReg(ARM::SP);
+
+ // If the frame has variable sized objects then the epilogue must restore
+ // the sp from fp. We can assume there's an FP here since hasFP already
+ // checks for hasVarSizedObjects.
+ if (MFI->hasVarSizedObjects())
+ AFI->setShouldRestoreSPFromFP(true);
}
static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
@@ -221,7 +227,8 @@
if (AFI->shouldRestoreSPFromFP()) {
NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
// Reset SP based on frame pointer only if the stack frame extends beyond
- // frame pointer stack slot or target is ELF and the function has FP.
+ // frame pointer stack slot, the target is ELF and the function has FP, or
+ // the target uses var sized objects.
if (NumBytes) {
assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) &&
"No scratch register to restore SP from FP!");