Re-apply r110655 with fixes. Epilogue must restore sp from fp if the function stack frame has a var-sized object.
Also added a test case to check for the added benefit of this patch: it's optimizing away the unnecessary restore of sp from fp for some non-leaf functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110707 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMMachineFunctionInfo.h b/lib/Target/ARM/ARMMachineFunctionInfo.h
index 7e57a1c..514c26b 100644
--- a/lib/Target/ARM/ARMMachineFunctionInfo.h
+++ b/lib/Target/ARM/ARMMachineFunctionInfo.h
@@ -43,6 +43,10 @@
/// processFunctionBeforeCalleeSavedScan().
bool HasStackFrame;
+ /// RestoreSPFromFP - True if epilogue should restore SP from FP. Set by
+ /// emitPrologue.
+ bool RestoreSPFromFP;
+
/// LRSpilledForFarJump - True if the LR register has been for spilled to
/// enable far jump.
bool LRSpilledForFarJump;
@@ -95,7 +99,7 @@
ARMFunctionInfo() :
isThumb(false),
hasThumb2(false),
- VarArgsRegSaveSize(0), HasStackFrame(false),
+ VarArgsRegSaveSize(0), HasStackFrame(false), RestoreSPFromFP(false),
LRSpilledForFarJump(false),
FramePtrSpillOffset(0), GPRCS1Offset(0), GPRCS2Offset(0), DPRCSOffset(0),
GPRCS1Size(0), GPRCS2Size(0), DPRCSSize(0),
@@ -106,7 +110,7 @@
explicit ARMFunctionInfo(MachineFunction &MF) :
isThumb(MF.getTarget().getSubtarget<ARMSubtarget>().isThumb()),
hasThumb2(MF.getTarget().getSubtarget<ARMSubtarget>().hasThumb2()),
- VarArgsRegSaveSize(0), HasStackFrame(false),
+ VarArgsRegSaveSize(0), HasStackFrame(false), RestoreSPFromFP(false),
LRSpilledForFarJump(false),
FramePtrSpillOffset(0), GPRCS1Offset(0), GPRCS2Offset(0), DPRCSOffset(0),
GPRCS1Size(0), GPRCS2Size(0), DPRCSSize(0),
@@ -125,6 +129,9 @@
bool hasStackFrame() const { return HasStackFrame; }
void setHasStackFrame(bool s) { HasStackFrame = s; }
+ bool shouldRestoreSPFromFP() const { return RestoreSPFromFP; }
+ void setShouldRestoreSPFromFP(bool s) { RestoreSPFromFP = s; }
+
bool isLRSpilledForFarJump() const { return LRSpilledForFarJump; }
void setLRIsSpilledForFarJump(bool s) { LRSpilledForFarJump = s; }