Index: llvm/trunk/lib/Passes/PassBuilder.cpp =================================================================== --- llvm/trunk/lib/Passes/PassBuilder.cpp +++ llvm/trunk/lib/Passes/PassBuilder.cpp @@ -1185,6 +1185,10 @@ // Break up allocas FPM.addPass(SROA()); + // LTO provides additional opportunities for tailcall elimination due to + // link-time inlining, and visibility of nocapture attribute. + FPM.addPass(TailCallElimPass()); + // Run a few AA driver optimizations here and now to cleanup the code. MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM))); Index: llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp =================================================================== --- llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp +++ llvm/trunk/lib/Transforms/IPO/PassManagerBuilder.cpp @@ -896,6 +896,10 @@ // Break up allocas PM.add(createSROAPass()); + // LTO provides additional opportunities for tailcall elimination due to + // link-time inlining, and visibility of nocapture attribute. + PM.add(createTailCallEliminationPass()); + // Run a few AA driven optimizations here and now, to cleanup the code. PM.add(createPostOrderFunctionAttrsLegacyPass()); // Add nocapture. PM.add(createGlobalsAAWrapperPass()); // IP alias analysis. Index: llvm/trunk/test/LTO/X86/tailcallelim.ll =================================================================== --- llvm/trunk/test/LTO/X86/tailcallelim.ll +++ llvm/trunk/test/LTO/X86/tailcallelim.ll @@ -0,0 +1,22 @@ +; Check that the LTO pipelines add the Tail Call Elimination pass. + +; RUN: llvm-as < %s > %t1 +; RUN: llvm-lto -o %t2 %t1 --exported-symbol=foo -save-merged-module +; RUN: llvm-dis < %t2.merged.bc | FileCheck %s + +; RUN: llvm-lto2 run -r %t1,foo,plx -r %t1,bar,plx -o %t3 %t1 -save-temps +; RUN: llvm-dis < %t3.0.4.opt.bc | FileCheck %s + +; RUN: llvm-lto2 run -r %t1,foo,plx -r %t1,bar,plx -o %t4 %t1 -save-temps -use-new-pm +; RUN: llvm-dis < %t4.0.4.opt.bc | FileCheck %s + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +define void @foo() { +; CHECK: tail call void @bar() + call void @bar() + ret void +} + +declare void @bar() Index: llvm/trunk/test/Other/new-pm-lto-defaults.ll =================================================================== --- llvm/trunk/test/Other/new-pm-lto-defaults.ll +++ llvm/trunk/test/Other/new-pm-lto-defaults.ll @@ -81,6 +81,7 @@ ; CHECK-O2-NEXT: Running pass: JumpThreadingPass ; CHECK-O2-NEXT: Running analysis: LazyValueAnalysis ; CHECK-O2-NEXT: Running pass: SROA on foo +; CHECK-O2-NEXT: Running pass: TailCallElimPass on foo ; CHECK-O2-NEXT: Finished llvm::Function pass manager run. ; CHECK-O2-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor<{{.*}}PostOrderFunctionAttrsPass> ; CHECK-O2-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>