From 28f02fdd76f4efc05d14649e0eec90ce8e71e17e Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 21 Sep 2009 19:47:04 +0000
Subject: [PATCH] Change MachineMemOperand's alignment value to be the
 alignment of the base pointer, without the offset. This matches MemSDNode's
 new alignment behavior, and holds more interesting information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82473 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/CodeGen/MachineMemOperand.h  | 16 ++++++++++++----
 lib/CodeGen/MachineInstr.cpp              |  2 +-
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp |  4 ++--
 lib/CodeGen/StackSlotColoring.cpp         |  2 +-
 lib/CodeGen/TargetInstrInfoImpl.cpp       |  2 +-
 5 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/include/llvm/CodeGen/MachineMemOperand.h b/include/llvm/CodeGen/MachineMemOperand.h
index de238e48d10..1b01c4893ef 100644
--- a/include/llvm/CodeGen/MachineMemOperand.h
+++ b/include/llvm/CodeGen/MachineMemOperand.h
@@ -16,6 +16,8 @@
 #ifndef LLVM_CODEGEN_MACHINEMEMOPERAND_H
 #define LLVM_CODEGEN_MACHINEMEMOPERAND_H
 
+#include "llvm/Support/MathExtras.h"
+
 namespace llvm {
 
 class Value;
@@ -47,9 +49,9 @@ public:
   };
 
   /// MachineMemOperand - Construct an MachineMemOperand object with the
-  /// specified address Value, flags, offset, size, and alignment.
+  /// specified address Value, flags, offset, size, and base alignment.
   MachineMemOperand(const Value *v, unsigned int f, int64_t o, uint64_t s,
-                    unsigned int a);
+                    unsigned int base_alignment);
 
   /// getValue - Return the base address of the memory access. This may either
   /// be a normal LLVM IR Value, or one of the special values used in CodeGen.
@@ -72,8 +74,14 @@ public:
   uint64_t getSize() const { return Size; }
 
   /// getAlignment - Return the minimum known alignment in bytes of the
-  /// memory reference.
-  unsigned int getAlignment() const { return (1u << (Flags >> 3)) >> 1; }
+  /// actual memory reference.
+  uint64_t getAlignment() const {
+    return MinAlign(getBaseAlignment(), getOffset());
+  }
+
+  /// getBaseAlignment - Return the minimum known alignment in bytes of the
+  /// base address, without the offset.
+  uint64_t getBaseAlignment() const { return (1u << (Flags >> 3)) >> 1; }
 
   bool isLoad() const { return Flags & MOLoad; }
   bool isStore() const { return Flags & MOStore; }
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index cf6597d8091..2f5964f1408 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -284,7 +284,7 @@ MachineMemOperand::MachineMemOperand(const Value *v, unsigned int f,
                                      int64_t o, uint64_t s, unsigned int a)
   : Offset(o), Size(s), V(v),
     Flags((f & 7) | ((Log2_32(a) + 1) << 3)) {
-  assert(isPowerOf2_32(a) && "Alignment is not a power of 2!");
+  assert(getBaseAlignment() == a && "Alignment is not a power of 2!");
   assert((isLoad() || isStore()) && "Not a load/store!");
 }
 
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 669526780b4..87ea19be869 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5015,10 +5015,10 @@ MachineMemOperand MemSDNode::getMemOperand() const {
   dyn_cast<const FrameIndexSDNode>(getBasePtr().getNode());
   if (!getSrcValue() && FI)
     return MachineMemOperand(PseudoSourceValue::getFixedStack(FI->getIndex()),
-                             Flags, 0, Size, getAlignment());
+                             Flags, 0, Size, getOriginalAlignment());
   else
     return MachineMemOperand(getSrcValue(), Flags, getSrcValueOffset(),
-                             Size, getAlignment());
+                             Size, getOriginalAlignment());
 }
 
 /// Profile - Gather unique data for the node.
diff --git a/lib/CodeGen/StackSlotColoring.cpp b/lib/CodeGen/StackSlotColoring.cpp
index e62c0506b3e..7d88dad6c8c 100644
--- a/lib/CodeGen/StackSlotColoring.cpp
+++ b/lib/CodeGen/StackSlotColoring.cpp
@@ -473,7 +473,7 @@ void StackSlotColoring::RewriteInstruction(MachineInstr *MI, int OldFI,
     else {
       MachineMemOperand MMO(PseudoSourceValue::getFixedStack(NewFI),
                             MMOs[i].getFlags(), MMOs[i].getOffset(),
-                            MMOs[i].getSize(),  MMOs[i].getAlignment());
+                            MMOs[i].getSize(),  MMOs[i].getBaseAlignment());
       MI->addMemOperand(MF, MMO);
     }
   }
diff --git a/lib/CodeGen/TargetInstrInfoImpl.cpp b/lib/CodeGen/TargetInstrInfoImpl.cpp
index 8aca0ccd424..f184cb74f0a 100644
--- a/lib/CodeGen/TargetInstrInfoImpl.cpp
+++ b/lib/CodeGen/TargetInstrInfoImpl.cpp
@@ -205,7 +205,7 @@ TargetInstrInfo::foldMemoryOperand(MachineFunction &MF,
   assert(MFI.getObjectOffset(FrameIndex) != -1);
   MachineMemOperand MMO(PseudoSourceValue::getFixedStack(FrameIndex),
                         Flags,
-                        MFI.getObjectOffset(FrameIndex),
+                        /*Offset=*/0,
                         MFI.getObjectSize(FrameIndex),
                         MFI.getObjectAlignment(FrameIndex));
   NewMI->addMemOperand(MF, MMO);
-- 
2.34.1