From 12fe2b1b82fe825d023f40a98931381e84fbc9d3 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 2 May 2004 05:02:03 +0000 Subject: [PATCH] Do not infinitely "unroll" single BB loops. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13315 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SimplifyCFG.cpp | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index a1b917ff3e9..a5153d65e32 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -804,12 +804,12 @@ bool llvm::SimplifyCFG(BasicBlock *BB) { // If this basic block is ONLY a setcc and a branch, and if a predecessor // branches to us and one of our successors, fold the setcc into the // predecessor and use logical operations to pick the right destination. + BasicBlock *TrueDest = BI->getSuccessor(0); + BasicBlock *FalseDest = BI->getSuccessor(1); if (Instruction *Cond = dyn_cast(BI->getCondition())) if (Cond->getParent() == BB && &BB->front() == Cond && - Cond->getNext() == BI && Cond->hasOneUse()) { - BasicBlock *TrueDest = BI->getSuccessor(0); - BasicBlock *FalseDest = BI->getSuccessor(1); - + Cond->getNext() == BI && Cond->hasOneUse() && + TrueDest != BB && FalseDest != BB) for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI!=E; ++PI) if (BranchInst *PBI = dyn_cast((*PI)->getTerminator())) if (PBI->isConditional() && SafeToMergeTerminators(BI, PBI)) { @@ -853,7 +853,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) { return SimplifyCFG(BB) | 1; } } - } // If this block ends with a branch instruction, and if there is one // predecessor, see if the previous block ended with a branch on the same