[GC] Remove so called PreCall safepoints

Remove another bit of unused configuration potential from GCStrategy.  It's not entirely clear what the intention here was, but from the docs, it sounds like this may have been subsumed by patchable call support.

Note: This change is deliberately small to make it clear that while implemented, there's nothing using the option.  A following NFC will do most of the simplifications.
llvm-svn: 346701

1 files changed, 2 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/GCRootLowering.cpp b/llvm/lib/CodeGen/GCRootLowering.cpp
index 8f9df36d84b..fff76f540f5 100644
--- a/llvm/lib/CodeGen/GCRootLowering.cpp
+++ b/llvm/lib/CodeGen/GCRootLowering.cpp
@@ -263,16 +263,11 @@ MCSymbol *GCMachineCodeAnalysis::InsertLabel(MachineBasicBlock &MBB,
 }
 
 void GCMachineCodeAnalysis::VisitCallPoint(MachineBasicBlock::iterator CI) {
-  // Find the return address (next instruction), too, so as to bracket the call
-  // instruction.
+  // Find the return address (next instruction), since that's what will be on
+  // the stack when the call is suspended and we need to inspect the stack.
   MachineBasicBlock::iterator RAI = CI;
   ++RAI;
 
-  if (FI->getStrategy().needsSafePoint(GC::PreCall)) {
-    MCSymbol *Label = InsertLabel(*CI->getParent(), CI, CI->getDebugLoc());
-    FI->addSafePoint(GC::PreCall, Label, CI->getDebugLoc());
-  }
-
   if (FI->getStrategy().needsSafePoint(GC::PostCall)) {
     MCSymbol *Label = InsertLabel(*CI->getParent(), RAI, CI->getDebugLoc());
     FI->addSafePoint(GC::PostCall, Label, CI->getDebugLoc());