Revert r319482 and r319483 "[memcpyopt] Teach memcpyopt to optimize across 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.

llvm-svn: 319873

1 files changed, 3 insertions, 28 deletions

diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index cd3e4ba88bc..9c870b42a74 100644
--- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/llvm/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);