From e7a9ac929f32a9ec74a09a64daea107ea4ee116e Mon Sep 17 00:00:00 2001
From: Duncan Sands <baldrick@free.fr>
Date: Fri, 9 Nov 2007 08:57:19 +0000
Subject: [PATCH] Fix some load/store logic that would be wrong for apints on
 big-endian machines if the bitwidth is not a multiple of 8.  Introduce a new
 helper, MVT::getStoreSizeInBits, and use it.

llvm-svn: 43934
---
 llvm/include/llvm/CodeGen/ValueTypes.h             |  7 +++++++
 llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp      | 12 ++++++++----
 llvm/lib/CodeGen/SelectionDAG/LegalizeDAGTypes.cpp |  4 ++--
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/llvm/include/llvm/CodeGen/ValueTypes.h b/llvm/include/llvm/CodeGen/ValueTypes.h
index 780482b07933..6edf97a52c10 100644
--- a/llvm/include/llvm/CodeGen/ValueTypes.h
+++ b/llvm/include/llvm/CodeGen/ValueTypes.h
@@ -243,6 +243,13 @@ namespace MVT {  // MVT = Machine Value Types
     }
   }
 
+  /// MVT::getStoreSizeInBits - Return the number of bits overwritten by a
+  /// store of the specified value type.
+  ///
+  static inline unsigned getStoreSizeInBits(ValueType VT) {
+    return (getSizeInBits(VT) + 7)/8*8;
+  }
+
   /// MVT::getIntegerType - Returns the ValueType that represents an integer
   /// with the given number of bits.
   ///
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 73d7db413f14..7a6e55e98494 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1713,8 +1713,9 @@ SDOperand DAGCombiner::visitAND(SDNode *N) {
         // For big endian targets, we need to add an offset to the pointer to
         // load the correct bytes.  For little endian systems, we merely need to
         // read fewer bytes from the same pointer.
-        unsigned PtrOff =
-          (MVT::getSizeInBits(LoadedVT) - MVT::getSizeInBits(EVT)) / 8;
+        unsigned LVTStoreBytes = MVT::getStoreSizeInBits(LoadedVT)/8;
+        unsigned EVTStoreBytes = MVT::getStoreSizeInBits(EVT)/8;
+        unsigned PtrOff = LVTStoreBytes - EVTStoreBytes;
         unsigned Alignment = LN0->getAlignment();
         SDOperand NewPtr = LN0->getBasePtr();
         if (!TLI.isLittleEndian()) {
@@ -2991,8 +2992,11 @@ SDOperand DAGCombiner::ReduceLoadWidth(SDNode *N) {
     MVT::ValueType PtrType = N0.getOperand(1).getValueType();
     // For big endian targets, we need to adjust the offset to the pointer to
     // load the correct bytes.
-    if (!TLI.isLittleEndian())
-      ShAmt = MVT::getSizeInBits(N0.getValueType()) - ShAmt - EVTBits;
+    if (!TLI.isLittleEndian()) {
+      unsigned LVTStoreBits = MVT::getStoreSizeInBits(N0.getValueType());
+      unsigned EVTStoreBits = MVT::getStoreSizeInBits(EVT);
+      ShAmt = LVTStoreBits - EVTStoreBits - ShAmt;
+    }
     uint64_t PtrOff =  ShAmt / 8;
     unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff);
     SDOperand NewPtr = DAG.getNode(ISD::ADD, PtrType, LN0->getBasePtr(),
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAGTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAGTypes.cpp
index 11431ee08619..825134130c36 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAGTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAGTypes.cpp
@@ -1036,7 +1036,7 @@ void DAGTypeLegalizer::ExpandResult_LOAD(LoadSDNode *N,
     // Big-endian - high bits are at low addresses.  Favor aligned loads at
     // the cost of some bit-fiddling.
     MVT::ValueType EVT = N->getLoadedVT();
-    unsigned EBytes = (MVT::getSizeInBits(EVT) + 7)/8;
+    unsigned EBytes = MVT::getStoreSizeInBits(EVT)/8;
     unsigned IncrementSize = MVT::getSizeInBits(NVT)/8;
     unsigned ExcessBits = (EBytes - IncrementSize)*8;
 
@@ -2069,7 +2069,7 @@ SDOperand DAGTypeLegalizer::ExpandOperand_STORE(StoreSDNode *N, unsigned OpNo) {
     GetExpandedOp(N->getValue(), Lo, Hi);
 
     MVT::ValueType EVT = N->getStoredVT();
-    unsigned EBytes = (MVT::getSizeInBits(EVT) + 7)/8;
+    unsigned EBytes = MVT::getStoreSizeInBits(EVT)/8;
     unsigned IncrementSize = MVT::getSizeInBits(NVT)/8;
     unsigned ExcessBits = (EBytes - IncrementSize)*8;
     MVT::ValueType HiVT =