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/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index db550b1..c3d60ad 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -742,14 +742,15 @@
unsigned
ARMTargetLowering::getRegPressureLimit(const TargetRegisterClass *RC,
MachineFunction &MF) const {
- unsigned FPDiff = RegInfo->hasFP(MF) ? 1 : 0;
switch (RC->getID()) {
default:
return 0;
case ARM::tGPRRegClassID:
- return 5 - FPDiff;
- case ARM::GPRRegClassID:
- return 10 - FPDiff - (Subtarget->isR9Reserved() ? 1 : 0);
+ return RegInfo->hasFP(MF) ? 4 : 5;
+ case ARM::GPRRegClassID: {
+ unsigned FP = RegInfo->hasFP(MF) ? 1 : 0;
+ return 10 - FP - (Subtarget->isR9Reserved() ? 1 : 0);
+ }
case ARM::SPRRegClassID: // Currently not used as 'rep' register class.
case ARM::DPRRegClassID:
return 32 - 10;