Revert "[ISel] Match all bits when merge undef(s) for DAG combine"

This reverts commit 5fe5aa284efed1ee1492e1f266351b35f0a8bb69.

1 files changed, 5 insertions, 11 deletions

diff --git a/llvm/lib/Support/APInt.cpp b/llvm/lib/Support/APInt.cpp
index f74178b..acc68fe 100644
--- a/llvm/lib/Support/APInt.cpp
+++ b/llvm/lib/Support/APInt.cpp
@@ -2968,8 +2968,7 @@ llvm::APIntOps::GetMostSignificantDifferentBit(const APInt &A, const APInt &B) {
   return A.getBitWidth() - ((A ^ B).countLeadingZeros() + 1);
 }
 
-APInt llvm::APIntOps::ScaleBitMask(const APInt &A, unsigned NewBitWidth,
-                                   bool MatchAllBits) {
+APInt llvm::APIntOps::ScaleBitMask(const APInt &A, unsigned NewBitWidth) {
   unsigned OldBitWidth = A.getBitWidth();
   assert((((OldBitWidth % NewBitWidth) == 0) ||
           ((NewBitWidth % OldBitWidth) == 0)) &&
@@ -2993,16 +2992,11 @@ APInt llvm::APIntOps::ScaleBitMask(const APInt &A, unsigned NewBitWidth,
       if (A[i])
         NewA.setBits(i * Scale, (i + 1) * Scale);
   } else {
+    // Merge bits - if any old bit is set, then set scale equivalent new bit.
     unsigned Scale = OldBitWidth / NewBitWidth;
-    for (unsigned i = 0; i != NewBitWidth; ++i) {
-      if (MatchAllBits) {
-        if (A.extractBits(Scale, i * Scale).isAllOnes())
-          NewA.setBit(i);
-      } else {
-        if (!A.extractBits(Scale, i * Scale).isZero())
-          NewA.setBit(i);
-      }
-    }
+    for (unsigned i = 0; i != NewBitWidth; ++i)
+      if (!A.extractBits(Scale, i * Scale).isZero())
+        NewA.setBit(i);
   }
 
   return NewA;