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| author | Christopher Lamb <christopher.lamb@gmail.com> | 2007-12-10 07:24:06 +0000 |
|---|---|---|
| committer | Christopher Lamb <christopher.lamb@gmail.com> | 2007-12-10 07:24:06 +0000 |
| commit | ff9045441499e076604a4f648c63de4fb9d0e64a (patch) | |
| tree | 269a1e0d787265ac3f793513d1320da8ee4f7379 /lib | |
| parent | 3e1980d0d56d7f7570e5c3000233bc21848ae0c6 (diff) | |
| download | external_llvm-ff9045441499e076604a4f648c63de4fb9d0e64a.zip external_llvm-ff9045441499e076604a4f648c63de4fb9d0e64a.tar.gz external_llvm-ff9045441499e076604a4f648c63de4fb9d0e64a.tar.bz2 | |
Improve branch folding by recgonizing that explict successor relationships impact the value of fall-through choices.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44785 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/CodeGen/BranchFolding.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp index d4b1e90..0f8c662 100644 --- a/lib/CodeGen/BranchFolding.cpp +++ b/lib/CodeGen/BranchFolding.cpp @@ -775,6 +775,11 @@ static bool IsBetterFallthrough(MachineBasicBlock *MBB1, // optimize branches that branch to either a return block or an assert block // into a fallthrough to the return. if (MBB1->empty() || MBB2->empty()) return false; + + // If there is a clear successor ordering we make sure that one block + // will fall through to the next + if (MBB1->isSuccessor(MBB2)) return true; + if (MBB2->isSuccessor(MBB1)) return false; MachineInstr *MBB1I = --MBB1->end(); MachineInstr *MBB2I = --MBB2->end(); |