From: Chad Rosier <mcrosier@codeaurora.org>
Date: Tue, 9 Feb 2016 19:42:19 +0000 (+0000)
Subject: [AArch64] Add a FIXME about invalid KILL markers after the ld/st opt pass.
X-Git-Tag: llvmorg-3.9.0-rc1~14696
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3f8b09da3fb9a3b78d7813b4adc2ac5916c6f25b;p=platform%2Fupstream%2Fllvm.git

[AArch64] Add a FIXME about invalid KILL markers after the ld/st opt pass.

llvm-svn: 260264
---

diff --git a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
index 9f454b2..f85d6a8 100644
--- a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp
@@ -1911,6 +1911,11 @@ bool AArch64LoadStoreOpt::runOnMachineFunction(MachineFunction &Fn) {
 // FIXME: Do we need/want a pre-alloc pass like ARM has to try to keep
 // loads and stores near one another?
 
+// FIXME: When pairing store instructions it's very possible for this pass to
+// hoist a store with a KILL marker above another use (without a KILL marker).
+// The resulting IR is invalid, but nothing uses the KILL markers after this
+// pass, so it's never caused a problem in practice.
+
 /// createAArch64LoadStoreOptimizationPass - returns an instance of the
 /// load / store optimization pass.
 FunctionPass *llvm::createAArch64LoadStoreOptimizationPass() {