From: Chris Lattner <sabre@nondot.org>
Date: Sat, 9 Oct 2004 02:50:40 +0000 (+0000)
Subject: Implement sub.ll:test17, -X/C -> X/-C
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a052f8297ab4b9bdc8b3ef5bd65b95b439c3cf56;p=oota-llvm.git

Implement sub.ll:test17, -X/C -> X/-C


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16863 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 5b477b3a409..f663ae6137f 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -946,6 +946,11 @@ Instruction *InstCombiner::visitDiv(BinaryOperator &I) {
           return new ShiftInst(Instruction::Shr, I.getOperand(0),
                                ConstantUInt::get(Type::UByteTy, C));
 
+    // -X/C -> X/-C
+    if (RHS->getType()->isSigned())
+      if (Value *LHSNeg = dyn_castNegVal(I.getOperand(0)))
+        return BinaryOperator::createDiv(LHSNeg, ConstantExpr::getNeg(RHS));
+
     if (isa<PHINode>(I.getOperand(0)) && !RHS->isNullValue())
       if (Instruction *NV = FoldOpIntoPhi(I))
         return NV;