LPM: Stop threading `Pass *` through all of the loop utility APIs. NFC

A large number of loop utility functions take a `Pass *` and reach
into it to find out which analyses to preserve. There are a number of
problems with this:

- The APIs have access to pretty well any Pass state they want, so
  it's hard to tell what they may or may not do.

- Other APIs have copied these and pass around a `Pass *` even though
  they don't even use it. Some of these just hand a nullptr to the API
  since the callers don't even have a pass available.

- Passes in the new pass manager don't work like the current ones, so
  the APIs can't be used as is there.

Instead, we should explicitly thread the analysis results that we
actually care about through these APIs. This is both simpler and more
reusable.

llvm-svn: 255669

1 files changed, 4 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index 58715fa..ddd8775 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -595,10 +595,8 @@ void IVVisitor::anchor() { }
 /// Simplify instructions that use this induction variable
 /// by using ScalarEvolution to analyze the IV's recurrence.
 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
-                       LPPassManager *LPM, SmallVectorImpl<WeakVH> &Dead, IVVisitor *V)
-{
-  LoopInfo *LI = &LPM->getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-
+                       LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead,
+                       IVVisitor *V) {
   SimplifyIndvar SIV(LI->getLoopFor(CurrIV->getParent()), SE, DT, LI, Dead);
   SIV.simplifyUsers(CurrIV, V);
   return SIV.hasChanged();
@@ -607,10 +605,10 @@ bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
 /// Simplify users of induction variables within this
 /// loop. This does not actually change or add IVs.
 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
-                     LPPassManager *LPM, SmallVectorImpl<WeakVH> &Dead) {
+                     LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead) {
   bool Changed = false;
   for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) {
-    Changed |= simplifyUsersOfIV(cast<PHINode>(I), SE, DT, LPM, Dead);
+    Changed |= simplifyUsersOfIV(cast<PHINode>(I), SE, DT, LI, Dead);
   }
   return Changed;
 }