From 511be2a158907c99ee3309e43e3d2a1031c83701 Mon Sep 17 00:00:00 2001
From: Philip Reames <listmail@philipreames.com>
Date: Fri, 2 Aug 2019 20:17:37 +0000
Subject: [PATCH] [Statepoints] Fix overalignment of loads in no-realign-stack
 functions

This really should have been part of 366765.  For some reason, I forgot to handle the corresponding load side, and the readable test cases (using deopt vs statepoints) turned out to be overly reduced.  Oops.

As seen in the test change, the problem was that we were using a load with alignment expectations rather than the unaligned variant when the stack alignment was less than that prefered type alignment.

llvm-svn: 367718
---
 .../CodeGen/SelectionDAG/StatepointLowering.cpp    | 23 ++++++++++++++--------
 .../CodeGen/X86/statepoint-no-realign-stack.ll     |  2 +-
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
index beacabe..fad98b6 100644
--- a/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/StatepointLowering.cpp
@@ -1016,20 +1016,27 @@ void SelectionDAGBuilder::visitGCRelocate(const GCRelocateInst &Relocate) {
     return;
   }
 
-  SDValue SpillSlot =
-    DAG.getTargetFrameIndex(*DerivedPtrLocation, getFrameIndexTy());
+  unsigned Index = *DerivedPtrLocation;
+  SDValue SpillSlot = DAG.getTargetFrameIndex(Index, getFrameIndexTy());
 
   // Note: We know all of these reloads are independent, but don't bother to
   // exploit that chain wise.  DAGCombine will happily do so as needed, so
   // doing it here would be a small compile time win at most.
   SDValue Chain = getRoot();
 
-  SDValue SpillLoad =
-      DAG.getLoad(DAG.getTargetLoweringInfo().getValueType(DAG.getDataLayout(),
-                                                           Relocate.getType()),
-                  getCurSDLoc(), Chain, SpillSlot,
-                  MachinePointerInfo::getFixedStack(DAG.getMachineFunction(),
-                                                    *DerivedPtrLocation));
+  auto &MF = DAG.getMachineFunction();
+  auto &MFI = MF.getFrameInfo();
+  auto PtrInfo = MachinePointerInfo::getFixedStack(MF, Index);
+  auto *LoadMMO =
+    MF.getMachineMemOperand(PtrInfo, MachineMemOperand::MOLoad, 
+                            MFI.getObjectSize(Index),
+                            MFI.getObjectAlignment(Index));
+
+  auto LoadVT = DAG.getTargetLoweringInfo().getValueType(DAG.getDataLayout(),
+                                                         Relocate.getType());
+
+  SDValue SpillLoad = DAG.getLoad(LoadVT, getCurSDLoc(), Chain,
+                                  SpillSlot, LoadMMO);
 
   DAG.setRoot(SpillLoad.getValue(1));
 
diff --git a/llvm/test/CodeGen/X86/statepoint-no-realign-stack.ll b/llvm/test/CodeGen/X86/statepoint-no-realign-stack.ll
index 0a1c244..40e721b 100644
--- a/llvm/test/CodeGen/X86/statepoint-no-realign-stack.ll
+++ b/llvm/test/CodeGen/X86/statepoint-no-realign-stack.ll
@@ -90,7 +90,7 @@ define <4 x i8 addrspace(1)*> @spillfill_no_realign(<4 x i8 addrspace(1)*> %obj)
 ; CHECK-NEXT:    vzeroupper
 ; CHECK-NEXT:    callq do_safepoint
 ; CHECK-NEXT:  .Ltmp3:
-; CHECK-NEXT:    vmovaps (%rsp), %ymm0
+; CHECK-NEXT:    vmovups (%rsp), %ymm0
 ; CHECK-NEXT:    addq $40, %rsp
 ; CHECK-NEXT:    .cfi_def_cfa_offset 8
 ; CHECK-NEXT:    retq
-- 
2.7.4