From f8131c99de2ac66be4307ae24f2db44d12bc9b3f Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Wed, 29 Oct 2008 17:46:26 +0000 Subject: Fix PR2967 by not deleting volatile load/stores that occur before unreachable. I don't really see this as being needed, but there is little harm from doing it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58385 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SimplifyCFG.cpp | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp') diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 7f4133630d..596c5643e5 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1932,7 +1932,18 @@ bool llvm::SimplifyCFG(BasicBlock *BB) { while (Unreachable != BB->begin()) { BasicBlock::iterator BBI = Unreachable; --BBI; + // Do not delete instructions that can have side effects, like calls + // (which may never return) and volatile loads and stores. if (isa(BBI)) break; + + if (StoreInst *SI = dyn_cast(BBI)) + if (SI->isVolatile()) + break; + + if (LoadInst *LI = dyn_cast(BBI)) + if (LI->isVolatile()) + break; + // Delete this instruction BB->getInstList().erase(BBI); Changed = true; -- cgit v1.2.3-18-g5258