Stop trying to have instcombine preserve LCSSA form: this was not

effective in avoiding recomputation of LCSSA form; the widespread
use of instsimplify (which looks through phi nodes) means it was
not preserving LCSSA form anyway; and instcombine is no longer
scheduled in the middle of the loop passes so this doesn't matter
anymore.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130301 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -76,7 +76,6 @@ INITIALIZE_PASS(InstCombiner, "instcombine",
                 "Combine redundant instructions", false, false)
 
 void InstCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addPreservedID(LCSSAID);
   AU.setPreservesCFG();
 }
 
@@ -1637,7 +1636,6 @@ bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {
 
 
 bool InstCombiner::runOnFunction(Function &F) {
-  MustPreserveLCSSA = mustPreserveAnalysisID(LCSSAID);
   TD = getAnalysisIfAvailable<TargetData>();