diff options
| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-08-20 21:39:52 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-08-20 21:39:52 +0000 |
| commit | e7fdef420d0c8a825555d246da259342c48bd527 (patch) | |
| tree | 547217afeba3ac83e232e628a24c768f2ab6bf87 /lib/CodeGen/MachineVerifier.cpp | |
| parent | 2c5a960b0eae0634da6e1854111b35f475e65335 (diff) | |
Don't add CFG edges for redundant conditional branches.
IR that hasn't been through SimplifyCFG can look like this:
br i1 %b, label %r, label %r
Make sure we don't create duplicate Machine CFG edges in this case.
Fix the machine code verifier to accept conditional branches with a
single CFG edge.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162230 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/MachineVerifier.cpp')
| -rw-r--r-- | lib/CodeGen/MachineVerifier.cpp | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/lib/CodeGen/MachineVerifier.cpp b/lib/CodeGen/MachineVerifier.cpp index f3e310ca3e..852c169254 100644 --- a/lib/CodeGen/MachineVerifier.cpp +++ b/lib/CodeGen/MachineVerifier.cpp @@ -580,7 +580,15 @@ MachineVerifier::visitMachineBasicBlockBefore(const MachineBasicBlock *MBB) { ++MBBI; if (MBBI == MF->end()) { report("MBB conditionally falls through out of function!", MBB); - } if (MBB->succ_size() != 2) { + } if (MBB->succ_size() == 1) { + // A conditional branch with only one successor is weird, but allowed. + if (&*MBBI != TBB) + report("MBB exits via conditional branch/fall-through but only has " + "one CFG successor!", MBB); + else if (TBB != *MBB->succ_begin()) + report("MBB exits via conditional branch/fall-through but the CFG " + "successor don't match the actual successor!", MBB); + } else if (MBB->succ_size() != 2) { report("MBB exits via conditional branch/fall-through but doesn't have " "exactly two CFG successors!", MBB); } else if (!matchPair(MBB->succ_begin(), TBB, MBBI)) { @@ -600,7 +608,15 @@ MachineVerifier::visitMachineBasicBlockBefore(const MachineBasicBlock *MBB) { } else if (TBB && FBB) { // Block conditionally branches somewhere, otherwise branches // somewhere else. - if (MBB->succ_size() != 2) { + if (MBB->succ_size() == 1) { + // A conditional branch with only one successor is weird, but allowed. + if (FBB != TBB) + report("MBB exits via conditional branch/branch through but only has " + "one CFG successor!", MBB); + else if (TBB != *MBB->succ_begin()) + report("MBB exits via conditional branch/branch through but the CFG " + "successor don't match the actual successor!", MBB); + } else if (MBB->succ_size() != 2) { report("MBB exits via conditional branch/branch but doesn't have " "exactly two CFG successors!", MBB); } else if (!matchPair(MBB->succ_begin(), TBB, FBB)) { |