From d1c58ed8a7d51ee476b0b1638fa3a8bb8b0b445a Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanaka@mips.com>
Date: Sat, 9 Nov 2013 02:38:51 +0000
Subject: [mips] Make sure there is a chain edge dependency between loads that
 read formal arguments on the stack and stores created afterwards. We need
 this to ensure tail call optimized function calls do not write over the
 argument area of the stack before it is read out.

llvm-svn: 194309
---
 llvm/lib/Target/Mips/MipsISelLowering.cpp |  8 +++++---
 llvm/test/CodeGen/Mips/i64arg.ll          | 14 +++++++-------
 llvm/test/CodeGen/Mips/tailcall.ll        | 13 +++++++++++++
 3 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 7a0e666ecfe..5f82b4e69c8 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -2650,9 +2650,11 @@ MipsTargetLowering::LowerFormalArguments(SDValue Chain,
 
       // Create load nodes to retrieve arguments from the stack
       SDValue FIN = DAG.getFrameIndex(FI, getPointerTy());
-      InVals.push_back(DAG.getLoad(ValVT, DL, Chain, FIN,
-                                   MachinePointerInfo::getFixedStack(FI),
-                                   false, false, false, 0));
+      SDValue Load = DAG.getLoad(ValVT, DL, Chain, FIN,
+                                 MachinePointerInfo::getFixedStack(FI),
+                                 false, false, false, 0);
+      InVals.push_back(Load);
+      OutChains.push_back(Load.getValue(1));
     }
   }
 
diff --git a/llvm/test/CodeGen/Mips/i64arg.ll b/llvm/test/CodeGen/Mips/i64arg.ll
index b038ad5bf74..5b2d1351803 100644
--- a/llvm/test/CodeGen/Mips/i64arg.ll
+++ b/llvm/test/CodeGen/Mips/i64arg.ll
@@ -2,16 +2,16 @@
 
 define void @f1(i64 %ll1, float %f, i64 %ll, i32 %i, float %f2) nounwind {
 entry:
-; CHECK: move $[[R1:[0-9]+]], $5
-; CHECK: move $[[R0:[0-9]+]], $4
-; CHECK: ori $6, ${{[0-9]+}}, 3855
-; CHECK: ori $7, ${{[0-9]+}}, 22136
-; CHECK: lw  $25, %call16(ff1)
+; CHECK-DAG: lw $[[R2:[0-9]+]], 80($sp)
+; CHECK-DAG: lw $[[R3:[0-9]+]], 84($sp)
+; CHECK-DAG: move $[[R1:[0-9]+]], $5
+; CHECK-DAG: move $[[R0:[0-9]+]], $4
+; CHECK-DAG: ori $6, ${{[0-9]+}}, 3855
+; CHECK-DAG: ori $7, ${{[0-9]+}}, 22136
+; CHECK-DAG: lw  $25, %call16(ff1)
 ; CHECK: jalr
   tail call void @ff1(i32 %i, i64 1085102592623924856) nounwind
 ; CHECK-DAG: lw $25, %call16(ff2)
-; CHECK-DAG: lw $[[R2:[0-9]+]], 80($sp)
-; CHECK-DAG: lw $[[R3:[0-9]+]], 84($sp)
 ; CHECK-DAG: move $4, $[[R2]]
 ; CHECK-DAG: move $5, $[[R3]]
 ; CHECK: jalr $25
diff --git a/llvm/test/CodeGen/Mips/tailcall.ll b/llvm/test/CodeGen/Mips/tailcall.ll
index bcd33fca70e..30f47abc06c 100644
--- a/llvm/test/CodeGen/Mips/tailcall.ll
+++ b/llvm/test/CodeGen/Mips/tailcall.ll
@@ -243,3 +243,16 @@ entry:
   ret i32 %call
 }
 
+; Check that there is a chain edge between the load and store nodes.
+;
+; PIC32-LABEL: caller14:
+; PIC32: lw ${{[0-9]+}}, 16($sp)
+; PIC32: sw $4, 16($sp)
+
+define void @caller14(i32 %a, i32 %b, i32 %c, i32 %d, i32 %e) {
+entry:
+  tail call void @callee14(i32 %e, i32 %b, i32 %c, i32 %d, i32 %a)
+  ret void
+}
+
+declare void @callee14(i32, i32, i32, i32, i32)
-- 
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