Index: llvm/lib/Transforms/Utils/Local.cpp =================================================================== --- llvm/lib/Transforms/Utils/Local.cpp +++ llvm/lib/Transforms/Utils/Local.cpp @@ -182,6 +182,8 @@ TheOnlyDest = SI->case_begin()->getCaseSuccessor(); } + bool Changed = false; + // Figure out which case it goes to. for (auto i = SI->case_begin(), e = SI->case_end(); i != e;) { // Found case matching a constant operand? @@ -220,6 +222,7 @@ DefaultDest->removePredecessor(ParentBB); i = SI->removeCase(i); e = SI->case_end(); + Changed = true; if (DTU) DTU->applyUpdatesPermissive( {{DominatorTree::Delete, ParentBB, DefaultDest}}); @@ -308,7 +311,7 @@ SI->eraseFromParent(); return true; } - return false; + return Changed; } if (auto *IBI = dyn_cast(T)) { Index: llvm/test/Transforms/SimplifyCFG/merge-default.ll =================================================================== --- /dev/null +++ llvm/test/Transforms/SimplifyCFG/merge-default.ll @@ -0,0 +1,45 @@ +; RUN: opt -simplifycfg -S < %s | FileCheck %s + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +declare void @g() +declare void @f() + +define void @foo(i32 %Kind) { +; CHECK-LABEL: @foo( +; CHECK-NEXT:entry: +; CHECK-NEXT: switch i32 %Kind, label %sw.epilog [ +; CHECK-NEXT: i32 15, label %sw.bb2 +; CHECK-NEXT: i32 2, label %sw.bb +; CHECK-NEXT: ] +; CHECK: sw.bb: +; CHECK-NEXT: call void @g() +; CHECK-NEXT: call void @g() +; CHECK-NEXT: br label %sw.epilog +; CHECK: sw.bb2: +; CHECK-NEXT: call void @f() +; CHECK-NEXT: br label %sw.epilog +; CHECK: sw.epilog: +; CHECK-NEXT: ret void +; CHECK-NEXT:} + +entry: + switch i32 %Kind, label %sw.epilog [ + i32 1, label %sw.epilog + i32 2, label %sw.bb + i32 15, label %sw.bb2 + ] + +sw.bb: + call void @g() + call void @g() + br label %sw.epilog + +sw.bb2: + call void @f() + br label %sw.epilog + +sw.epilog: + ret void +}