[llvm] r341336 - [InstCombine] simplify xor/not folds; NFCI

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Mon Sep  3 11:40:56 2018
New Revision: 341336

URL: http://llvm.org/viewvc/llvm-project?rev=341336&view=rev
Log:
[InstCombine] simplify xor/not folds; NFCI

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

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp?rev=341336&r1=341335&r2=341336&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp Mon Sep  3 11:40:56 2018
@@ -2685,20 +2685,17 @@ Instruction *InstCombiner::visitXor(Bina
     // the 'not' by inverting the constant and using the opposite shift type.
     // Canonicalization rules ensure that only a negative constant uses 'ashr',
     // but we must check that in case that transform has not fired yet.
+
+    // ~(C >>s Y) --> ~C >>u Y (when inverting the replicated sign bits)
     Constant *C;
     if (match(NotVal, m_AShr(m_Constant(C), m_Value(Y))) &&
-        match(C, m_Negative())) {
-      // ~(C >>s Y) --> ~C >>u Y (when inverting the replicated sign bits)
-      Constant *NotC = ConstantExpr::getNot(C);
-      return BinaryOperator::CreateLShr(NotC, Y);
-    }
+        match(C, m_Negative()))
+      return BinaryOperator::CreateLShr(ConstantExpr::getNot(C), Y);
 
+    // ~(C >>u Y) --> ~C >>s Y (when inverting the replicated sign bits)
     if (match(NotVal, m_LShr(m_Constant(C), m_Value(Y))) &&
-        match(C, m_NonNegative())) {
-      // ~(C >>u Y) --> ~C >>s Y (when inverting the replicated sign bits)
-      Constant *NotC = ConstantExpr::getNot(C);
-      return BinaryOperator::CreateAShr(NotC, Y);
-    }
+        match(C, m_NonNegative()))
+      return BinaryOperator::CreateAShr(ConstantExpr::getNot(C), Y);
 
     // ~(X + C) --> -(C + 1) - X
     if (match(Op0, m_Add(m_Value(X), m_Constant(C))))
@@ -2717,18 +2714,15 @@ Instruction *InstCombiner::visitXor(Bina
     if (match(Op1, m_APInt(RHSC))) {
       Value *X;
       const APInt *C;
-      if (match(Op0, m_Sub(m_APInt(C), m_Value(X)))) {
-        if (RHSC->isSignMask()) {
-          // (C - X) ^ signmask -> (C + signmask - X)
-          Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
-          return BinaryOperator::CreateSub(NewC, X);
-        }
-      } else if (match(Op0, m_Add(m_Value(X), m_APInt(C)))) {
-        if (RHSC->isSignMask()) {
-          // (X + C) ^ signmask -> (X + C + signmask)
-          Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
-          return BinaryOperator::CreateAdd(X, NewC);
-        }
+      if (RHSC->isSignMask() && match(Op0, m_Sub(m_APInt(C), m_Value(X)))) {
+        // (C - X) ^ signmask -> (C + signmask - X)
+        Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
+        return BinaryOperator::CreateSub(NewC, X);
+      }
+      if (RHSC->isSignMask() && match(Op0, m_Add(m_Value(X), m_APInt(C)))) {
+        // (X + C) ^ signmask -> (X + C + signmask)
+        Constant *NewC = ConstantInt::get(I.getType(), *C + *RHSC);
+        return BinaryOperator::CreateAdd(X, NewC);
       }
 
       // (X|C1)^C2 -> X^(C1^C2) iff X&~C1 == 0