Vendor import of llvm release_39 branch r276489:vendor/llvm/llvm-release_39-r276489

https://llvm.org/svn/llvm-project/llvm/branches/release_39@276489

1 files changed, 14 insertions, 4 deletions

diff --git a/lib/CodeGen/TargetFrameLoweringImpl.cpp b/lib/CodeGen/TargetFrameLoweringImpl.cpp
index 679ade185e1c..cac7e63af328 100644
--- a/lib/CodeGen/TargetFrameLoweringImpl.cpp
+++ b/lib/CodeGen/TargetFrameLoweringImpl.cpp
@@ -12,13 +12,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/BitVector.h"
-#include "llvm/Target/TargetFrameLowering.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Function.h"
+#include "llvm/Target/TargetFrameLowering.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
 #include <cstdlib>
@@ -59,16 +60,25 @@ bool TargetFrameLowering::needsFrameIndexResolution(
 void TargetFrameLowering::determineCalleeSaves(MachineFunction &MF,
                                                BitVector &SavedRegs,
                                                RegScavenger *RS) const {
-  // Get the callee saved register list...
   const TargetRegisterInfo &TRI = *MF.getSubtarget().getRegisterInfo();
+
+  // Resize before the early returns. Some backends expect that
+  // SavedRegs.size() == TRI.getNumRegs() after this call even if there are no
+  // saved registers.
+  SavedRegs.resize(TRI.getNumRegs());
+
+  // When interprocedural register allocation is enabled caller saved registers
+  // are preferred over callee saved registers.
+  if (MF.getTarget().Options.EnableIPRA && isSafeForNoCSROpt(MF.getFunction()))
+    return;
+
+  // Get the callee saved register list...
   const MCPhysReg *CSRegs = TRI.getCalleeSavedRegs(&MF);
 
   // Early exit if there are no callee saved registers.
   if (!CSRegs || CSRegs[0] == 0)
     return;
 
-  SavedRegs.resize(TRI.getNumRegs());
-
   // In Naked functions we aren't going to save any registers.
   if (MF.getFunction()->hasFnAttribute(Attribute::Naked))
     return;