Consider any instruction that modifies the stack pointer to be
a scheduling region boundary. This isn't necessary for
correctness; it helps with compile time, as it avoids the need
for data- and anti-dependencies from all spills and reloads on
the stack-pointer modification.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64255 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index 617b4ac..fd7135f 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -28,6 +28,7 @@
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
+#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
@@ -221,6 +222,15 @@
if (MI->getDesc().isTerminator() || MI->isLabel())
return true;
+ // Don't attempt to schedule around any instruction that modifies
+ // a stack-oriented pointer, as it's unlikely to be profitable. This
+ // saves compile time, because it doesn't require every single
+ // stack slot reference to depend on the instruction that does the
+ // modification.
+ const TargetLowering &TLI = *MF.getTarget().getTargetLowering();
+ if (MI->modifiesRegister(TLI.getStackPointerRegisterToSaveRestore()))
+ return true;
+
return false;
}