[PowerPC] Add a flag for experimenting with subreg liveness tracking

This cannot yet be enabled by default, it causes ~50 miscompiles in the test
suite.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225497 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCSubtarget.cpp b/lib/Target/PowerPC/PPCSubtarget.cpp
index fb47c910c2fb51385cb9bc8c023c7e7583a670db..d8ba1c71a0f53a9c481e2ebb3c55b3574d18c88e 100644 (file)
--- a/lib/Target/PowerPC/PPCSubtarget.cpp
+++ b/lib/Target/PowerPC/PPCSubtarget.cpp
@@ -19,6 +19,7 @@
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalValue.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Target/TargetMachine.h"
@@ -32,6 +33,9 @@ using namespace llvm;
 #define GET_SUBTARGETINFO_CTOR
 #include "PPCGenSubtargetInfo.inc"
 
+static cl::opt<bool> UseSubRegLiveness("ppc-track-subreg-liveness",
+cl::desc("Enable subregister liveness tracking for PPC"), cl::Hidden);
+
 /// Return the datalayout string of a subtarget.
 static std::string getDataLayoutString(const Triple &T) {
   bool is64Bit = T.getArch() == Triple::ppc64 || T.getArch() == Triple::ppc64le;
@@ -234,3 +238,7 @@ bool PPCSubtarget::useAA() const {
   return needsAggressiveScheduling(DarwinDirective);
 }
 
+bool PPCSubtarget::enableSubRegLiveness() const {
+  return UseSubRegLiveness;
+}
+

diff --git a/lib/Target/PowerPC/PPCSubtarget.h b/lib/Target/PowerPC/PPCSubtarget.h
index de5f92a971ba6b0bbccc3238780dd7becc16f5d1..b33b7370a912136adc1d4c66892214b7ec85ff2f 100644 (file)
--- a/lib/Target/PowerPC/PPCSubtarget.h
+++ b/lib/Target/PowerPC/PPCSubtarget.h
@@ -259,6 +259,8 @@ public:
                            MachineInstr *end,
                            unsigned NumRegionInstrs) const override;
   bool useAA() const override;
+
+  bool enableSubRegLiveness() const override;
 };
 } // End llvm namespace