From 56a5886b20433569e5eb9c5b1ad350ef0c0e0596 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Sun, 31 Jan 2010 00:59:31 +0000 Subject: [PATCH] Do not mark no-return calls tail calls. It'll screw up special calls like longjmp and it doesn't make much sense for performance reason. If my logic is faulty, please let me know. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94937 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/TailRecursionElimination.cpp | 9 +++++---- test/Transforms/TailCallElim/no-return-calls.ll | 12 ++++++++++++ 2 files changed, 17 insertions(+), 4 deletions(-) create mode 100644 test/Transforms/TailCallElim/no-return-calls.ll diff --git a/lib/Transforms/Scalar/TailRecursionElimination.cpp b/lib/Transforms/Scalar/TailRecursionElimination.cpp index 162d902cfa4..913dd73cc17 100644 --- a/lib/Transforms/Scalar/TailRecursionElimination.cpp +++ b/lib/Transforms/Scalar/TailRecursionElimination.cpp @@ -184,10 +184,11 @@ bool TailCallElim::runOnFunction(Function &F) { if (!FunctionContainsEscapingAllocas) for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) - if (CallInst *CI = dyn_cast(I)) { - CI->setTailCall(); - MadeChange = true; - } + if (CallInst *CI = dyn_cast(I)) + if (!CI->doesNotReturn()) { + CI->setTailCall(); + MadeChange = true; + } return MadeChange; } diff --git a/test/Transforms/TailCallElim/no-return-calls.ll b/test/Transforms/TailCallElim/no-return-calls.ll new file mode 100644 index 00000000000..f5643ae3330 --- /dev/null +++ b/test/Transforms/TailCallElim/no-return-calls.ll @@ -0,0 +1,12 @@ +; RUN: opt < %s -tailcallelim -S | FileCheck %s + +define void @t() nounwind ssp { +entry: +; CHECK: entry: +; CHECK: %0 = call i32 @foo() +; CHECK: ret void + %0 = call i32 @foo() nounwind noreturn + ret void +} + +declare i32 @foo() -- 2.11.0