From 96fc7ea76dd22a15e67e318c6f930a3ca9aa4fad Mon Sep 17 00:00:00 2001
From: Rick Lavoie <rlavoie@fb.com>
Date: Mon, 26 Aug 2019 18:42:04 -0700
Subject: [PATCH] Remove trivial nops before jump optimizations

Summary:
Some vasm passes can leave behind trivial nops. These will eventually
get cleaned up before code emission, but they may hang around for
multiple passes. The presence of trivial nops can inhibit some
optimizations that optimizeJmps performs, so clean them up before
running the pass.

Reviewed By: ottoni, mxw

Differential Revision: D17053304

fbshipit-source-id: 2f80cb6ad72a639667ddf95e62585726f9327ff9
---
 hphp/runtime/vm/jit/vasm-jumps.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hphp/runtime/vm/jit/vasm-jumps.cpp b/hphp/runtime/vm/jit/vasm-jumps.cpp
index e350a54604c..2f4c27ad436 100644
--- a/hphp/runtime/vm/jit/vasm-jumps.cpp
+++ b/hphp/runtime/vm/jit/vasm-jumps.cpp
@@ -274,6 +274,8 @@ void optimizeJmps(Vunit& unit, MaybeVinstrId clobber) {
   bool changed = false;
   bool ever_changed = false;
 
+  removeTrivialNops(unit);
+
   // The number of incoming edges from (reachable) predecessors for each block.
   jit::vector<int> npreds(unit.blocks.size(), 0);
 
-- 
2.11.4.GIT