Revert r319482 and r319483 "[memcpyopt] Teach memcpyopt to optimize a…

…cross basic blocks"

This caused PR35519.

> [memcpyopt] Teach memcpyopt to optimize across basic blocks
>
> This teaches memcpyopt to make a non-local memdep query when a local query
> indicates that the dependency is non-local. This notably allows it to
> eliminate many more llvm.memcpy calls in common Rust code, often by 20-30%.
>
> Fixes PR28958.
>
> Differential Revision: https://reviews.llvm.org/D38374
>

> [memcpyopt] Commit file missed in r319482.
>
> This change was meant to be included with r319482 but was accidentally
> omitted.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319873 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/MemoryDependenceAnalysis.h

@@ -407,12 +407,6 @@ class MemoryDependenceResults {
   void getNonLocalPointerDependency(Instruction *QueryInst,
                                     SmallVectorImpl<NonLocalDepResult> &Result);
 
-  /// Perform a dependency query specifically for QueryInst's access to Loc.
-  /// The other comments for getNonLocalPointerDependency apply here as well.
-  void getNonLocalPointerDependencyFrom(Instruction *QueryInst,
-                                        const MemoryLocation &Loc, bool isLoad,
-                                        SmallVectorImpl<NonLocalDepResult> &Result);
-
   /// Removes an instruction from the dependence analysis, updating the
   /// dependence of instructions that previously depended on it.
   void removeInstruction(Instruction *InstToRemove);

lib/Analysis/MemoryDependenceAnalysis.cpp

@@ -917,14 +917,6 @@ void MemoryDependenceResults::getNonLocalPointerDependency(
     Instruction *QueryInst, SmallVectorImpl<NonLocalDepResult> &Result) {
   const MemoryLocation Loc = MemoryLocation::get(QueryInst);
   bool isLoad = isa<LoadInst>(QueryInst);
-  return getNonLocalPointerDependencyFrom(QueryInst, Loc, isLoad, Result);
-}
-
-void MemoryDependenceResults::getNonLocalPointerDependencyFrom(
-    Instruction *QueryInst,
-    const MemoryLocation &Loc,
-    bool isLoad,
-    SmallVectorImpl<NonLocalDepResult> &Result) {
   BasicBlock *FromBB = QueryInst->getParent();
   assert(FromBB);
 

lib/Transforms/Scalar/MemCpyOptimizer.cpp

@@ -1031,22 +1031,9 @@ bool MemCpyOptPass::processMemCpyMemCpyDependence(MemCpyInst *M,
   //
   // NOTE: This is conservative, it will stop on any read from the source loc,
   // not just the defining memcpy.
-  MemoryLocation SourceLoc = MemoryLocation::getForSource(MDep);
-  MemDepResult SourceDep = MD->getPointerDependencyFrom(SourceLoc, false,
-                                                        M->getIterator(), M->getParent());
-
-  if (SourceDep.isNonLocal()) {
-    SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
-    MD->getNonLocalPointerDependencyFrom(M, SourceLoc, /*isLoad=*/false,
-                                         NonLocalDepResults);
-    if (NonLocalDepResults.size() == 1) {
-      SourceDep = NonLocalDepResults[0].getResult();
-      assert((!SourceDep.getInst() ||
-              LookupDomTree().dominates(SourceDep.getInst(), M)) &&
-             "when memdep returns exactly one result, it should dominate");
-    }
-  }
-
+  MemDepResult SourceDep =
+      MD->getPointerDependencyFrom(MemoryLocation::getForSource(MDep), false,
+                                   M->getIterator(), M->getParent());
   if (!SourceDep.isClobber() || SourceDep.getInst() != MDep)
     return false;
 
@@ -1248,18 +1235,6 @@ bool MemCpyOptPass::processMemCpy(MemCpyInst *M) {
   MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(
       SrcLoc, true, M->getIterator(), M->getParent());
 
-  if (SrcDepInfo.isNonLocal()) {
-    SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
-    MD->getNonLocalPointerDependencyFrom(M, SrcLoc, /*isLoad=*/true,
-                                         NonLocalDepResults);
-    if (NonLocalDepResults.size() == 1) {
-      SrcDepInfo = NonLocalDepResults[0].getResult();
-      assert((!SrcDepInfo.getInst() ||
-              LookupDomTree().dominates(SrcDepInfo.getInst(), M)) &&
-             "when memdep returns exactly one result, it should dominate");
-    }
-  }
-
   if (SrcDepInfo.isClobber()) {
     if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(SrcDepInfo.getInst()))
       return processMemCpyMemCpyDependence(M, MDep);