From 509b48a64a1baf497a85a2a1f86d9141b18cb1e1 Mon Sep 17 00:00:00 2001
From: Florian Hahn <flo@fhahn.com>
Date: Sat, 2 Feb 2019 14:42:27 +0000
Subject: [PATCH] [LCSSA] Add expensive verification of LCSSA form for
 sub-loops.

This assertion makes sure all sub-loops are in LCSSA form before
bringing their parent in LCSSA form. This precondition was added to
formLCSSA in D56848.

Reviewers: davide, efriedma, mzolotukhin

Reviewed By: davide

Differential Revision: https://reviews.llvm.org/D56921

llvm-svn: 352958
---
 llvm/lib/Transforms/Utils/LCSSA.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index 3a08977..2706766 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -305,6 +305,12 @@ bool llvm::formLCSSA(Loop &L, DominatorTree &DT, LoopInfo *LI,
                      ScalarEvolution *SE) {
   bool Changed = false;
 
+#ifdef EXPENSIVE_CHECKS
+  // Verify all sub-loops are in LCSSA form already.
+  for (Loop *SubLoop: L)
+    assert(SubLoop->isRecursivelyLCSSAForm(DT, *LI) && "Subloop not in LCSSA!");
+#endif
+
   SmallVector<BasicBlock *, 8> ExitBlocks;
   L.getExitBlocks(ExitBlocks);
   if (ExitBlocks.empty())
-- 
2.7.4