From d202e03fe56ca9c95ee20060f293f77cc2d77160 Mon Sep 17 00:00:00 2001 From: Christopher Lamb Date: Mon, 10 Dec 2007 07:24:06 +0000 Subject: Improve branch folding by recgonizing that explict successor relationships impact the value of fall-through choices. llvm-svn: 44785 --- llvm/lib/CodeGen/BranchFolding.cpp | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'llvm/lib/CodeGen/BranchFolding.cpp') diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp index d4b1e90fd54..0f8c6629bae 100644 --- a/llvm/lib/CodeGen/BranchFolding.cpp +++ b/llvm/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(); -- cgit v1.2.3