LiveIntervalAnalysis: Remove LiveVariables requirement

This requirement was a huge hack to keep LiveVariables alive because it
was optionally used by TwoAddressInstructionPass and PHIElimination.
However we have AnalysisUsage::addUsedIfAvailable() which we can use in
those passes.

This re-applies r260806 with LiveVariables manually added to PowerPC to
hopefully not break the stage 2 bots this time.

llvm-svn: 267954

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
index b21827418f8..77aab2dd031 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -15,6 +15,7 @@
 #include "PPC.h"
 #include "PPCTargetObjectFile.h"
 #include "PPCTargetTransformInfo.h"
+#include "llvm/CodeGen/LiveVariables.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/LegacyPassManager.h"
@@ -387,8 +388,14 @@ void PPCPassConfig::addPreRegAlloc() {
     insertPass(VSXFMAMutateEarly ? &RegisterCoalescerID : &MachineSchedulerID,
                &PPCVSXFMAMutateID);
   }
-  if (getPPCTargetMachine().getRelocationModel() == Reloc::PIC_)
+  if (getPPCTargetMachine().getRelocationModel() == Reloc::PIC_) {
+    // FIXME: LiveVariables should not be necessary here!
+    // PPCTLSDYnamicCallPass uses LiveIntervals which previously dependet on
+    // LiveVariables. This (unnecessary) dependency has been removed now,
+    // however a stage-2 clang build fails without LiveVariables computed here.
+    addPass(&LiveVariablesID, false);
     addPass(createPPCTLSDynamicCallPass());
+  }
   if (EnableExtraTOCRegDeps)
     addPass(createPPCTOCRegDepsPass());
 }