[llvm] a58b6ac - [NFC][LoopInterchange] Clean up of irrelevent dependency checking with

[via llvm-commits]

Author: Ram-NK
Date: 2022-10-04T14:54:08-04:00
New Revision: a58b6acf1f369141603cb58171bcd642eb6ee732

URL: https://github.com/llvm/llvm-project/commit/a58b6acf1f369141603cb58171bcd642eb6ee732
DIFF: https://github.com/llvm/llvm-project/commit/a58b6acf1f369141603cb58171bcd642eb6ee732.diff

LOG: [NFC][LoopInterchange] Clean up of irrelevent dependency checking with
isOuterMostDepPositive()

The function isOuterMostDepPositive() is checked after negative dependence
vectors are normalized to be non-negative, so there will not be any negative
dependency ('>' as the outermost non-equal sign) after normalization. And
therefore the check in isOuterMostDepPositive() is irrelevent and redundant.

Reviewed By: congzhe

Differential Revision: https://reviews.llvm.org/D132982

Added: 
    

Modified: 
    llvm/lib/Transforms/Scalar/LoopInterchange.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
index 460ff357b2b49..3cf35172b7499 100644
--- a/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInterchange.cpp
@@ -182,20 +182,6 @@ static void interChangeDependencies(CharMatrix &DepMatrix, unsigned FromIndx,
     std::swap(DepMatrix[I][ToIndx], DepMatrix[I][FromIndx]);
 }
 
-// Checks if outermost non '=','S'or'I' dependence in the dependence matrix is
-// '>'
-static bool isOuterMostDepPositive(CharMatrix &DepMatrix, unsigned Row,
-                                   unsigned Column) {
-  for (unsigned i = 0; i <= Column; ++i) {
-    if (DepMatrix[Row][i] == '<')
-      return false;
-    if (DepMatrix[Row][i] == '>')
-      return true;
-  }
-  // All dependencies were '=','S' or 'I'
-  return false;
-}
-
 // Checks if no dependence exist in the dependency matrix in Row before Column.
 static bool containsNoDependence(CharMatrix &DepMatrix, unsigned Row,
                                  unsigned Column) {
@@ -210,9 +196,6 @@ static bool containsNoDependence(CharMatrix &DepMatrix, unsigned Row,
 static bool validDepInterchange(CharMatrix &DepMatrix, unsigned Row,
                                 unsigned OuterLoopId, char InnerDep,
                                 char OuterDep) {
-  if (isOuterMostDepPositive(DepMatrix, Row, OuterLoopId))
-    return false;
-
   if (InnerDep == OuterDep)
     return true;