From 053546c31e4752e3d76e1f0915ddd6c8a3280351 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatanak@gmail.com>
Date: Wed, 25 May 2011 02:20:00 +0000
Subject: [PATCH] Fix lowering of DYNAMIC_STACKALLOC nodes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132030 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/Mips/MipsISelLowering.cpp | 22 ++++++++++++++++++++--
 test/CodeGen/Mips/alloca.ll          | 31 +++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+), 2 deletions(-)
 create mode 100644 test/CodeGen/Mips/alloca.ll

diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index cec19173c6f..93e7a23ac47 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -692,6 +692,13 @@ LowerFP_TO_SINT(SDValue Op, SelectionDAG &DAG) const
 SDValue MipsTargetLowering::
 LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const
 {
+  unsigned StackAlignment =
+    getTargetMachine().getFrameLowering()->getStackAlignment();
+  assert(StackAlignment >=
+         cast<ConstantSDNode>(Op.getOperand(2).getNode())->getZExtValue() &&
+         "Cannot lower if the alignment of the allocated space is larger than \
+          that of the stack.");
+
   SDValue Chain = Op.getOperand(0);
   SDValue Size = Op.getOperand(1);
   DebugLoc dl = Op.getDebugLoc();
@@ -705,11 +712,22 @@ LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const
 
   // The Sub result contains the new stack start address, so it
   // must be placed in the stack pointer register.
-  Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub);
+  Chain = DAG.getCopyToReg(StackPointer.getValue(1), dl, Mips::SP, Sub,
+                           SDValue());
+  SDValue NewSP = DAG.getCopyFromReg(Chain, dl, Mips::SP, MVT::i32,
+                                     Chain.getValue(1));
+  
+  // Align the allocated space.
+  MachineFunction &MF = DAG.getMachineFunction();
+  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
+  unsigned SPOffset = (MipsFI->getMaxCallFrameSize() + StackAlignment - 1) /
+                      StackAlignment * StackAlignment;
+  SDValue AllocPtr = DAG.getNode(ISD::ADD, dl, MVT::i32, NewSP,
+                                 DAG.getConstant(SPOffset, MVT::i32));
 
   // This node always has two return values: a new stack pointer
   // value and a chain
-  SDValue Ops[2] = { Sub, Chain };
+  SDValue Ops[2] = { AllocPtr, NewSP.getValue(1) };
   return DAG.getMergeValues(Ops, 2, dl);
 }
 
diff --git a/test/CodeGen/Mips/alloca.ll b/test/CodeGen/Mips/alloca.ll
new file mode 100644
index 00000000000..50eeecf991f
--- /dev/null
+++ b/test/CodeGen/Mips/alloca.ll
@@ -0,0 +1,31 @@
+; RUN: llc -march=mipsel -mcpu=4ke < %s | FileCheck %s
+
+define i32 @twoalloca(i32 %size) nounwind {
+entry:
+; CHECK: subu  $[[T0:[0-9]+]], $sp, $[[SZ:[0-9]+]]
+; CHECK: addu  $sp, $zero, $[[T0]]
+; CHECK: addu  $[[SP1:[0-9]+]], $zero, $sp
+; CHECK: subu  $[[T1:[0-9]+]], $sp, $[[SZ]]
+; CHECK: addu  $sp, $zero, $[[T1]]
+; CHECK: addu  $[[SP2:[0-9]+]], $zero, $sp
+; CHECK: lw  $25, %call16(foo)($gp)
+; CHECK: addiu $4, $[[SP1]], 24
+; CHECK: jalr  $25
+; CHECK: lw  $25, %call16(foo)($gp)
+; CHECK: addiu $4, $[[SP2]], 24
+; CHECK: jalr  $25
+  %tmp1 = alloca i8, i32 %size, align 4
+  %add.ptr = getelementptr inbounds i8* %tmp1, i32 5
+  store i8 97, i8* %add.ptr, align 1
+  %tmp4 = alloca i8, i32 %size, align 4
+  call void @foo2(double 1.000000e+00, double 2.000000e+00, i32 3) nounwind
+  %call = call i32 @foo(i8* %tmp1) nounwind
+  %call7 = call i32 @foo(i8* %tmp4) nounwind
+  %add = add nsw i32 %call7, %call
+  ret i32 %add
+}
+
+declare void @foo2(double, double, i32)
+
+declare i32 @foo(i8*)
+
-- 
2.11.0