[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.
 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194309 91177308-0d34-0410-b5e6-96231b3b80d8

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));
     }
   }
 

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

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)