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, 3 deletions

diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index 84bd670105e..bfb2cde030d 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -188,8 +188,9 @@ namespace {
       return Reg < regsReserved.size() && regsReserved.test(Reg);
     }
 
-    bool isAllocatable(unsigned Reg) {
-      return Reg < TRI->getNumRegs() && MRI->isAllocatable(Reg);
+    bool isAllocatable(unsigned Reg) const {
+      return Reg < TRI->getNumRegs() && TRI->isInAllocatableClass(Reg) &&
+        !regsReserved.test(Reg);
     }
 
     // Analysis information if available
@@ -526,7 +527,8 @@ void MachineVerifier::markReachable(const MachineBasicBlock *MBB) {
 
 void MachineVerifier::visitMachineFunctionBefore() {
   lastIndex = SlotIndex();
-  regsReserved = MRI->getReservedRegs();
+  regsReserved = MRI->reservedRegsFrozen() ? MRI->getReservedRegs()
+                                           : TRI->getReservedRegs(*MF);
 
   if (!MF->empty())
     markReachable(&MF->front());