diff options
| -rw-r--r-- | lib/CodeGen/MachineBasicBlock.cpp | 8 | ||||
| -rw-r--r-- | test/CodeGen/X86/block-placement.ll | 24 |
2 files changed, 32 insertions, 0 deletions
diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index f05b6c1..b9d1ef7 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -305,6 +305,14 @@ void MachineBasicBlock::updateTerminator() { assert(!TBB && "Found more than one non-landing-pad successor!"); TBB = *SI; } + + // If there is no non-landing-pad successor, the block has no + // fall-through edges to be concerned with. + if (!TBB) + return; + + // Finally update the unconditional successor to be reached via a branch + // if it would not be reached by fallthrough. if (!isLayoutSuccessor(TBB)) TII->InsertBranch(*this, TBB, 0, Cond, dl); } diff --git a/test/CodeGen/X86/block-placement.ll b/test/CodeGen/X86/block-placement.ll index 05d6f81..c03b03e 100644 --- a/test/CodeGen/X86/block-placement.ll +++ b/test/CodeGen/X86/block-placement.ll @@ -504,6 +504,30 @@ loop: br label %loop } +declare void @fake_throw() noreturn + +define void @test_eh_throw() { +; For blocks containing a 'throw' (or similar functionality), we have +; a no-return invoke. In this case, only EH successors will exist, and +; fallthrough simply won't occur. Make sure we don't crash trying to update +; terminators for such constructs. +; +; CHECK: test_eh_throw +; CHECK: %entry +; CHECK: %cleanup + +entry: + invoke void @fake_throw() to label %continue unwind label %cleanup + +continue: + unreachable + +cleanup: + %0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) + cleanup + unreachable +} + define void @test_unnatural_cfg_backwards_inner_loop() { ; Test that when we encounter an unnatural CFG structure after having formed ; a chain for an inner loop which happened to be laid out backwards we don't |