From 6bf861597c87d708336c6ed36678d91b75d1043c Mon Sep 17 00:00:00 2001
From: Max Kazantsev <max.kazantsev@azul.com>
Date: Tue, 12 Feb 2019 07:48:07 +0000
Subject: [LoopSimplifyCFG] Pay respect to LCSSA when removing dead blocks

Utility function that we use for blocks deletion always unconditionally removes
one-input Phis. In LoopSimplifyCFG, it can lead to breach of LCSSA form.
This patch alters this function to keep them if needed.

Differential Revision: https://reviews.llvm.org/D57231
Reviewed By: fedor.sergeev

llvm-svn: 353803
---
 llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp')

diff --git a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
index 01d770ca515..896f9dd001e 100644
--- a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
@@ -418,7 +418,7 @@ private:
       LI.removeBlock(BB);
     }
 
-    DetatchDeadBlocks(DeadLoopBlocks, &DTUpdates);
+    DetatchDeadBlocks(DeadLoopBlocks, &DTUpdates, /*KeepOneInputPHIs*/true);
     DTU.applyUpdates(DTUpdates);
     DTUpdates.clear();
     for (auto *BB : DeadLoopBlocks)
-- 
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