From 29c277197edb8ac410d3d625913091d8ebef8de7 Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Tue, 18 Dec 2012 22:55:07 +0000
Subject: [PATCH] Verify bundle flags for consistency in MachineVerifier.

The new bidirectional bundle flags are redundant, so inadvertent bundle
tearing can be detected in the machine code verifier.

llvm-svn: 170463
---
 llvm/lib/CodeGen/MachineVerifier.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index 62856f9..590c20a 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -307,6 +307,9 @@ bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) {
     visitMachineBasicBlockBefore(MFI);
     // Keep track of the current bundle header.
     const MachineInstr *CurBundle = 0;
+    // Do we expect the next instruction to be part of the same bundle?
+    bool InBundle = false;
+
     for (MachineBasicBlock::const_instr_iterator MBBI = MFI->instr_begin(),
            MBBE = MFI->instr_end(); MBBI != MBBE; ++MBBI) {
       if (MBBI->getParent() != MFI) {
@@ -314,6 +317,15 @@ bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) {
         *OS << "Instruction: " << *MBBI;
         continue;
       }
+
+      // Check for consistent bundle flags.
+      if (InBundle && !MBBI->isBundledWithPred())
+        report("Missing BundledPred flag, "
+               "BundledSucc was set on predecessor", MBBI);
+      if (!InBundle && MBBI->isBundledWithPred())
+        report("BundledPred flag is set, "
+               "but BundledSucc not set on predecessor", MBBI);
+
       // Is this a bundle header?
       if (!MBBI->isInsideBundle()) {
         if (CurBundle)
@@ -326,9 +338,14 @@ bool MachineVerifier::runOnMachineFunction(MachineFunction &MF) {
       for (unsigned I = 0, E = MBBI->getNumOperands(); I != E; ++I)
         visitMachineOperand(&MBBI->getOperand(I), I);
       visitMachineInstrAfter(MBBI);
+
+      // Was this the last bundled instruction?
+      InBundle = MBBI->isBundledWithSucc();
     }
     if (CurBundle)
       visitMachineBundleAfter(CurBundle);
+    if (InBundle)
+      report("BundledSucc flag set on last instruction in block", &MFI->back());
     visitMachineBasicBlockAfter(MFI);
   }
   visitMachineFunctionAfter();
-- 
2.7.4