[llvm] 14b0ae4 - [InstCombine] Remove redundant fold in foldUnsignedUnderflowCheck() (NFCI)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-10-24T16:57:18+02:00
New Revision: 14b0ae439ff8c92bce47f0b5dbe6d5a9f02de338

URL: https://github.com/llvm/llvm-project/commit/14b0ae439ff8c92bce47f0b5dbe6d5a9f02de338
DIFF: https://github.com/llvm/llvm-project/commit/14b0ae439ff8c92bce47f0b5dbe6d5a9f02de338.diff

LOG: [InstCombine] Remove redundant fold in foldUnsignedUnderflowCheck() (NFCI)

Base - Offset == 0 will get canonicalized to Base == Offset even
in multi-use contexts, at which point all of these patterns already
get handled by generic code.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 3e0218d9b76d1f7..cedd8f47fe651f2 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1099,39 +1099,6 @@ static Value *foldUnsignedUnderflowCheck(ICmpInst *ZeroICmp,
       return Builder.CreateICmpUGE(Builder.CreateNeg(B), A);
   }
 
-  Value *Base, *Offset;
-  if (!match(ZeroCmpOp, m_Sub(m_Value(Base), m_Value(Offset))))
-    return nullptr;
-
-  if (!match(UnsignedICmp,
-             m_c_ICmp(UnsignedPred, m_Specific(Base), m_Specific(Offset))) ||
-      !ICmpInst::isUnsigned(UnsignedPred))
-    return nullptr;
-
-  // Base >=/> Offset && (Base - Offset) != 0  <-->  Base > Offset
-  // (no overflow and not null)
-  if ((UnsignedPred == ICmpInst::ICMP_UGE ||
-       UnsignedPred == ICmpInst::ICMP_UGT) &&
-      EqPred == ICmpInst::ICMP_NE && IsAnd)
-    return Builder.CreateICmpUGT(Base, Offset);
-
-  // Base <=/< Offset || (Base - Offset) == 0  <-->  Base <= Offset
-  // (overflow or null)
-  if ((UnsignedPred == ICmpInst::ICMP_ULE ||
-       UnsignedPred == ICmpInst::ICMP_ULT) &&
-      EqPred == ICmpInst::ICMP_EQ && !IsAnd)
-    return Builder.CreateICmpULE(Base, Offset);
-
-  // Base <= Offset && (Base - Offset) != 0  -->  Base < Offset
-  if (UnsignedPred == ICmpInst::ICMP_ULE && EqPred == ICmpInst::ICMP_NE &&
-      IsAnd)
-    return Builder.CreateICmpULT(Base, Offset);
-
-  // Base > Offset || (Base - Offset) == 0  -->  Base >= Offset
-  if (UnsignedPred == ICmpInst::ICMP_UGT && EqPred == ICmpInst::ICMP_EQ &&
-      !IsAnd)
-    return Builder.CreateICmpUGE(Base, Offset);
-
   return nullptr;
 }