Revert r146184. I am seeing performance regression cause by this patch in one test...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146205 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 7740a75e42749f55ae25c8085e7560363191e904..dff81093634c78ec317881ecb66c2816557e0810 100644 (file)
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -485,16 +485,6 @@ MachineBasicBlock *MachineSinking::FindSuccToSinkTo(MachineInstr *MI,
       for (MachineBasicBlock::succ_iterator SI = ParentBlock->succ_begin(),
            E = ParentBlock->succ_end(); SI != E; ++SI) {
        MachineBasicBlock *SuccBlock = *SI;
-       // It is not possible to sink an instruction into its own block.  This can
-       // happen with loops.
-       if (ParentBlock == SuccBlock)
-         continue;
-
-       // It's not safe to sink instructions to EH landing pad. Control flow into
-       // landing pad is implicitly defined.
-       if (SuccBlock->isLandingPad())
-         continue;
-
         bool LocalUse = false;
         if (AllUsesDominatedByBlock(Reg, SuccBlock, ParentBlock,
                                     BreakPHIEdge, LocalUse)) {
@@ -511,6 +501,17 @@ MachineBasicBlock *MachineSinking::FindSuccToSinkTo(MachineInstr *MI,
         return NULL;
     }
   }
+
+  // It is not possible to sink an instruction into its own block.  This can
+  // happen with loops.
+  if (ParentBlock == SuccToSinkTo)
+    return NULL;
+
+  // It's not safe to sink instructions to EH landing pad. Control flow into
+  // landing pad is implicitly defined.
+  if (SuccToSinkTo && SuccToSinkTo->isLandingPad())
+    return NULL;
+
   return SuccToSinkTo;
 }