From 249716e8aef5ac234a9a29f3ed3d0a931884192e Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Fri, 27 Jul 2012 21:21:26 +0000 Subject: Teach CodeGenPrep to look past bitcast when it's duplicating return instruction into predecessor blocks to enable tail call optimization. rdar://11958338 llvm-svn: 160894 --- llvm/lib/Transforms/Utils/BasicBlockUtils.cpp | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'llvm/lib/Transforms/Utils/BasicBlockUtils.cpp') diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp index 5576432..2679b93 100644 --- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp +++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp @@ -659,10 +659,26 @@ ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB, // If the return instruction returns a value, and if the value was a // PHI node in "BB", propagate the right value into the return. for (User::op_iterator i = NewRet->op_begin(), e = NewRet->op_end(); - i != e; ++i) - if (PHINode *PN = dyn_cast(*i)) - if (PN->getParent() == BB) - *i = PN->getIncomingValueForBlock(Pred); + i != e; ++i) { + Value *V = *i; + Instruction *NewBC = 0; + if (BitCastInst *BCI = dyn_cast(V)) { + // Return value might be bitcasted. Clone and insert it before the + // return instruction. + V = BCI->getOperand(0); + NewBC = BCI->clone(); + Pred->getInstList().insert(NewRet, NewBC); + *i = NewBC; + } + if (PHINode *PN = dyn_cast(V)) { + if (PN->getParent() == BB) { + if (NewBC) + NewBC->setOperand(0, PN->getIncomingValueForBlock(Pred)); + else + *i = PN->getIncomingValueForBlock(Pred); + } + } + } // Update any PHI nodes in the returning block to realize that we no // longer branch to them. -- cgit v1.1