[Reassociate] Support some reassociation of vector xors

Summary:
Currently we don't try to do anything with vector xors.

This patch adds support for removing duplicate pairs from a chain of vector xors as its pretty easy to support. We still dont' try to combine the xors with and/ors, but I might try that in a future patch.

Reviewers: mcrosier, davide, resistor

Reviewed By: mcrosier

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34338

llvm-svn: 305704

1 files changed, 7 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp
index 4ce32e0eca7..313b1d12009 100644
--- a/llvm/lib/Transforms/Scalar/Reassociate.cpp
+++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp
@@ -1276,9 +1276,15 @@ Value *ReassociatePass::OptimizeXor(Instruction *I,
   if (Ops.size() == 1)
     return nullptr;
 
+  Type *Ty = Ops[0].Op->getType();
+
+  // TODO: We should optimize vector Xor instructions, but they are
+  // currently unsupported.
+  if (Ty->isVectorTy())
+    return nullptr;
+
   SmallVector<XorOpnd, 8> Opnds;
   SmallVector<XorOpnd*, 8> OpndPtrs;
-  Type *Ty = Ops[0].Op->getType();
   APInt ConstOpnd(Ty->getIntegerBitWidth(), 0);
 
   // Step 1: Convert ValueEntry to XorOpnd
@@ -2000,11 +2006,6 @@ void ReassociatePass::OptimizeInst(Instruction *I) {
   if (I->isCommutative())
     canonicalizeOperands(I);
 
-  // TODO: We should optimize vector Xor instructions, but they are
-  // currently unsupported.
-  if (I->getType()->isVectorTy() && I->getOpcode() == Instruction::Xor)
-    return;
-
   // Don't optimize floating point instructions that don't have unsafe algebra.
   if (I->getType()->isFPOrFPVectorTy() && !I->hasUnsafeAlgebra())
     return;