Re-commit : [PowerPC] Add handling for ColdCC calling convention and a pass to mark

candidates with coldcc attribute.

This recommits r322721 reverted due to sanitizer memory leak build bot failures.

Original commit message:
This patch adds support for the coldcc calling convention for Power.
This changes the set of non-volatile registers. It includes a pass to stress
test the implementation by marking all static directly called functions with
the coldcc attribute through the option -enable-coldcc-stress-test. It also
includes an option, -ppc-enable-coldcc, to add the coldcc attribute to
functions which are cold at all call sites based on BlockFrequencyInfo when
the containing function does not call any non cold functions.

Differential Revision: https://reviews.llvm.org/D38413

llvm-svn: 323778

1 files changed, 12 insertions, 2 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
index 7902da20a01..bdda9d13ad8 100644
--- a/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1950,7 +1950,14 @@ PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
     bool IsCRField = PPC::CR2 <= Reg && Reg <= PPC::CR4;
 
     // Add the callee-saved register as live-in; it's killed at the spill.
-    MBB.addLiveIn(Reg);
+    // Do not do this for callee-saved registers that are live-in to the
+    // function because they will already be marked live-in and this will be
+    // adding it for a second time. It is an error to add the same register
+    // to the set more than once.
+    const MachineRegisterInfo &MRI = MF->getRegInfo();
+    bool IsLiveIn = MRI.isLiveIn(Reg);
+    if (!IsLiveIn)
+       MBB.addLiveIn(Reg);
 
     if (CRSpilled && IsCRField) {
       CRMIB.addReg(Reg, RegState::ImplicitKill);
@@ -1980,7 +1987,10 @@ PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
       }
     } else {
       const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
-      TII.storeRegToStackSlot(MBB, MI, Reg, true,
+      // Use !IsLiveIn for the kill flag.
+      // We do not want to kill registers that are live in this function
+      // before their use because they will become undefined registers.
+      TII.storeRegToStackSlot(MBB, MI, Reg, !IsLiveIn,
                               CSI[i].getFrameIdx(), RC, TRI);
     }
   }