[GVN] Refactor handling of pointer-select in GVN pass

This patch introduces new type of memory dependency - Select to
consistently handle it like Def/Clobber dependency.

Differential Revision: https://reviews.llvm.org/D141619

1 files changed, 6 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
index 7a13e7a..960679b 100644
--- a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -592,6 +592,11 @@ MemDepResult MemoryDependenceResults::getSimplePointerDependencyFrom(
         return MemDepResult::getDef(Inst);
     }
 
+    // If we found a select instruction for MemLoc pointer, return it as
+    // Select dependency.
+    if (isa<SelectInst>(Inst) && MemLoc.Ptr == Inst)
+      return MemDepResult::getSelect(Inst);
+
     if (isInvariantLoad)
       continue;
 
@@ -962,7 +967,7 @@ MemDepResult MemoryDependenceResults::getNonLocalInfoForBlock(
   // If the block has a dependency (i.e. it isn't completely transparent to
   // the value), remember the reverse association because we just added it
   // to Cache!
-  if (!Dep.isDef() && !Dep.isClobber())
+  if (!Dep.isLocal())
     return Dep;
 
   // Keep the ReverseNonLocalPtrDeps map up to date so we can efficiently