[llvm] ae117e1 - [InstCombine] remove dead code for add (select cond, (sub), 0); NFC

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2022-09-06T12:19:50-04:00
New Revision: ae117e1c1ba68da48c70f5cd8cb3c666fbdd1b77

URL: https://github.com/llvm/llvm-project/commit/ae117e1c1ba68da48c70f5cd8cb3c666fbdd1b77
DIFF: https://github.com/llvm/llvm-project/commit/ae117e1c1ba68da48c70f5cd8cb3c666fbdd1b77.diff

LOG: [InstCombine] remove dead code for add (select cond, (sub), 0); NFC

This pattern is handled more generally in SimplifySelectsFeedingBinaryOp().
Tests to confirm that added to the add.ll test file in the previous commit.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index c8b3fd05a8db..b80064b29878 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1378,31 +1378,6 @@ Instruction *InstCombinerImpl::visitAdd(BinaryOperator &I) {
   if (haveNoCommonBitsSet(LHS, RHS, DL, &AC, &I, &DT))
     return BinaryOperator::CreateOr(LHS, RHS);
 
-  // add (select X 0 (sub n A)) A  -->  select X A n
-  {
-    SelectInst *SI = dyn_cast<SelectInst>(LHS);
-    Value *A = RHS;
-    if (!SI) {
-      SI = dyn_cast<SelectInst>(RHS);
-      A = LHS;
-    }
-    if (SI && SI->hasOneUse()) {
-      Value *TV = SI->getTrueValue();
-      Value *FV = SI->getFalseValue();
-      Value *N;
-
-      // Can we fold the add into the argument of the select?
-      // We check both true and false select arguments for a matching subtract.
-      if (match(FV, m_Zero()) && match(TV, m_Sub(m_Value(N), m_Specific(A))))
-        // Fold the add into the true select value.
-        return SelectInst::Create(SI->getCondition(), N, A);
-
-      if (match(TV, m_Zero()) && match(FV, m_Sub(m_Value(N), m_Specific(A))))
-        // Fold the add into the false select value.
-        return SelectInst::Create(SI->getCondition(), A, N);
-    }
-  }
-
   if (Instruction *Ext = narrowMathIfNoOverflow(I))
     return Ext;