From be6ceb6ebcfb48e09ffab297c1537c87383f0ce9 Mon Sep 17 00:00:00 2001
From: Nadav Rotem <nadav.rotem@intel.com>
Date: Sun, 28 Aug 2011 11:51:08 +0000
Subject: Bitcasts are transitive. Bitcast-Bitcast-X becomes Bitcast-X.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138722 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/InstCombine/InstCombineCasts.cpp | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'lib/Transforms/InstCombine/InstCombineCasts.cpp')

diff --git a/lib/Transforms/InstCombine/InstCombineCasts.cpp b/lib/Transforms/InstCombine/InstCombineCasts.cpp
index ba90bf6b5c..6c42c0c660 100644
--- a/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -1659,6 +1659,11 @@ Instruction *InstCombiner::visitBitCast(BitCastInst &CI) {
   if (DestTy == Src->getType())
     return ReplaceInstUsesWith(CI, Src);
 
+  // Bitcasts are transitive.
+  if (BitCastInst* BSrc = dyn_cast<BitCastInst>(Src)) {
+    return CastInst::Create(Instruction::BitCast, BSrc->getOperand(0), DestTy);
+  }
+
   if (PointerType *DstPTy = dyn_cast<PointerType>(DestTy)) {
     PointerType *SrcPTy = cast<PointerType>(SrcTy);
     Type *DstElTy = DstPTy->getElementType();
-- 
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