Register Data Flow: data flow graph

[oota-llvm.git] / lib / Target / PowerPC / PPCBranchSelector.cpp

diff --git a/lib/Target/PowerPC/PPCBranchSelector.cpp b/lib/Target/PowerPC/PPCBranchSelector.cpp
index 8a851d85255b7934447e59e1802e2d844007d7b7..73a5305197ad7b959c8f00652666bd9679535ebf 100644 (file)
--- a/lib/Target/PowerPC/PPCBranchSelector.cpp
+++ b/lib/Target/PowerPC/PPCBranchSelector.cpp
@@ -23,6 +23,7 @@
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "ppc-branch-select"
@@ -43,9 +44,9 @@ namespace {
     /// BlockSizes - The sizes of the basic blocks in the function.
     std::vector<unsigned> BlockSizes;
 
-    virtual bool runOnMachineFunction(MachineFunction &Fn);
+    bool runOnMachineFunction(MachineFunction &Fn) override;
 
-    virtual const char *getPassName() const {
+    const char *getPassName() const override {
       return "PowerPC Branch Selector";
     }
   };
@@ -64,16 +65,41 @@ FunctionPass *llvm::createPPCBranchSelectionPass() {
 
 bool PPCBSel::runOnMachineFunction(MachineFunction &Fn) {
   const PPCInstrInfo *TII =
-                static_cast<const PPCInstrInfo*>(Fn.getTarget().getInstrInfo());
+      static_cast<const PPCInstrInfo *>(Fn.getSubtarget().getInstrInfo());
   // Give the blocks of the function a dense, in-order, numbering.
   Fn.RenumberBlocks();
   BlockSizes.resize(Fn.getNumBlockIDs());
 
+  auto GetAlignmentAdjustment =
+    [TII](MachineBasicBlock &MBB, unsigned Offset) -> unsigned {
+    unsigned Align = MBB.getAlignment();
+    if (!Align)
+      return 0;
+
+    unsigned AlignAmt = 1 << Align;
+    unsigned ParentAlign = MBB.getParent()->getAlignment();
+
+    if (Align <= ParentAlign)
+      return OffsetToAlignment(Offset, AlignAmt);
+
+    // The alignment of this MBB is larger than the function's alignment, so we
+    // can't tell whether or not it will insert nops. Assume that it will.
+    return AlignAmt + OffsetToAlignment(Offset, AlignAmt);
+  };
+
   // Measure each MBB and compute a size for the entire function.
   unsigned FuncSize = 0;
   for (MachineFunction::iterator MFI = Fn.begin(), E = Fn.end(); MFI != E;
        ++MFI) {
-    MachineBasicBlock *MBB = MFI;
+    MachineBasicBlock *MBB = &*MFI;
+
+    // The end of the previous block may have extra nops if this block has an
+    // alignment requirement.
+    if (MBB->getNumber() > 0) {
+      unsigned AlignExtra = GetAlignmentAdjustment(*MBB, FuncSize);
+      BlockSizes[MBB->getNumber()-1] += AlignExtra;
+      FuncSize += AlignExtra;
+    }
 
     unsigned BlockSize = 0;
     for (MachineBasicBlock::iterator MBBI = MBB->begin(), EE = MBB->end();