ARM: Compute MaxCallFrame size early

This exposes a method in MachineFrameInfo that calculates
MaxCallFrameSize and calls it after instruction selection in the ARM
target.

This avoids
ARMBaseRegisterInfo::canRealignStack()/ARMFrameLowering::hasReservedCallFrame()
giving different answers in early/late phases of codegen.

The testcase shows a particular nasty example result of that where we
would fail to properly align an alloca.

Differential Revision: https://reviews.llvm.org/D32622

llvm-svn: 302303

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index f248a829b8e..bbf5b6665e6 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -14054,3 +14054,8 @@ void ARMTargetLowering::insertCopiesSplitCSR(
           .addReg(NewVR);
   }
 }
+
+void ARMTargetLowering::finalizeLowering(MachineFunction &MF) const {
+  MF.getFrameInfo().computeMaxCallFrameSize(MF);
+  TargetLoweringBase::finalizeLowering(MF);
+}