From 16865d06128c266b5505cc21f5d086d18173408c Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@mips.com>
Date: Fri, 24 Aug 2012 20:40:15 +0000
Subject: [PATCH] Disable Mips' delay slot filler when optimization level is
 O0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162589 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/Mips/MipsDelaySlotFiller.cpp |  4 +++-
 test/CodeGen/Mips/brdelayslot.ll        | 18 ++++++++++++------
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/lib/Target/Mips/MipsDelaySlotFiller.cpp b/lib/Target/Mips/MipsDelaySlotFiller.cpp
index 8fe3ba61712..e3c8ed75cf9 100644
--- a/lib/Target/Mips/MipsDelaySlotFiller.cpp
+++ b/lib/Target/Mips/MipsDelaySlotFiller.cpp
@@ -115,7 +115,9 @@ runOnMachineBasicBlock(MachineBasicBlock &MBB) {
 
       InstrIter D;
 
-      if (!DisableDelaySlotFiller && findDelayInstr(MBB, I, D)) {
+      // Delay slot filling is disabled at -O0.
+      if (!DisableDelaySlotFiller && (TM.getOptLevel() != CodeGenOpt::None) &&
+          findDelayInstr(MBB, I, D)) {
         MBB.splice(llvm::next(I), &MBB, D);
         ++UsefulSlots;
       } else
diff --git a/test/CodeGen/Mips/brdelayslot.ll b/test/CodeGen/Mips/brdelayslot.ll
index d2832da62b9..1b2fbc89321 100644
--- a/test/CodeGen/Mips/brdelayslot.ll
+++ b/test/CodeGen/Mips/brdelayslot.ll
@@ -1,12 +1,18 @@
-; RUN: llc -march=mipsel < %s | FileCheck %s
+; RUN: llc -march=mipsel -O0 < %s | FileCheck %s -check-prefix=None
+; RUN: llc -march=mipsel < %s | FileCheck %s -check-prefix=Default
 
 define void @foo1() nounwind {
 entry:
-; CHECK:      jalr 
-; CHECK-NOT:  nop 
-; CHECK:      jr 
-; CHECK-NOT:  nop
-; CHECK:      .end
+; Default:     jalr 
+; Default-NOT: nop 
+; Default:     jr 
+; Default-NOT: nop
+; Default:     .end
+; None: jalr 
+; None: nop 
+; None: jr 
+; None: nop
+; None: .end
 
   tail call void @foo2(i32 3) nounwind
   ret void