Spill R4 if it's going to be used to restore SP from FP.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123567 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMFrameLowering.cpp b/lib/Target/ARM/ARMFrameLowering.cpp
index b8cbf5d..0b514da 100644
--- a/lib/Target/ARM/ARMFrameLowering.cpp
+++ b/lib/Target/ARM/ARMFrameLowering.cpp
@@ -801,15 +801,23 @@
// Spill R4 if Thumb2 function requires stack realignment - it will be used as
// scratch register. Also spill R4 if Thumb2 function has varsized objects,
- // since it's always posible to restore sp from fp in a single instruction.
+ // since it's not always possible to restore sp from fp in a single
+ // instruction.
// FIXME: It will be better just to find spare register here.
if (AFI->isThumb2Function() &&
(MFI->hasVarSizedObjects() || RegInfo->needsStackRealignment(MF)))
MF.getRegInfo().setPhysRegUsed(ARM::R4);
- // Spill LR if Thumb1 function uses variable length argument lists.
- if (AFI->isThumb1OnlyFunction() && AFI->getVarArgsRegSaveSize() > 0)
- MF.getRegInfo().setPhysRegUsed(ARM::LR);
+ if (AFI->isThumb1OnlyFunction()) {
+ // Spill LR if Thumb1 function uses variable length argument lists.
+ if (AFI->getVarArgsRegSaveSize() > 0)
+ MF.getRegInfo().setPhysRegUsed(ARM::LR);
+
+ // Spill R4 if Thumb1 epilogue has to restore SP from FP since
+ // FIXME: It will be better just to find spare register here.
+ if (MFI->hasVarSizedObjects())
+ MF.getRegInfo().setPhysRegUsed(ARM::R4);
+ }
// Spill the BasePtr if it's used.
if (RegInfo->hasBasePointer(MF))
diff --git a/test/CodeGen/Thumb/2011-EpilogueBug.ll b/test/CodeGen/Thumb/2011-EpilogueBug.ll
new file mode 100644
index 0000000..16789e6
--- /dev/null
+++ b/test/CodeGen/Thumb/2011-EpilogueBug.ll
@@ -0,0 +1,17 @@
+; RUN: llc -mtriple=thumbv6-apple-darwin < %s | FileCheck %s
+; r8869722
+
+%struct.state = type { i32, %struct.info*, float**, i32, i32, i32, i32, i32, i32, i32, i32, i32, i64, i64, i64, i64, i64, i64, i8* }
+%struct.info = type { i32, i32, i32, i32, i32, i32, i32, i8* }
+
+define void @t1(%struct.state* %v) {
+; CHECK: push {r4
+ %tmp6 = load i32* null
+ %tmp8 = alloca float, i32 %tmp6
+ store i32 1, i32* null
+ br label %return
+
+return: ; preds = %0
+; CHECK: mov sp, r4
+ ret void
+}