llvm/test/Transforms/JumpThreading/lifetime-alloca.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -passes=jump-threading -S %s | FileCheck %s

; Test that JumpThreading does not create a PHI node for an alloca that is
; used by a lifetime intrinsic, which would violate the requirement that
; lifetime markers only operate on allocas.

define void @widget_dropped(i1 %arg) {
; CHECK-LABEL: @widget_dropped(
; CHECK-NEXT:  bb:
; CHECK-NEXT:    br i1 [[ARG:%.*]], label [[BB3:%.*]], label [[BB2:%.*]]
; CHECK:       bb2:
; CHECK-NEXT:    [[ALLOCA:%.*]] = alloca [4 x [4 x i32]], align 8
; CHECK-NEXT:    br label [[BB4:%.*]]
; CHECK:       bb3:
; CHECK-NEXT:    call void @dummy()
; CHECK-NEXT:    [[ALLOCA1:%.*]] = alloca [4 x [4 x i32]], align 8
; CHECK-NEXT:    br label [[BB4]]
; CHECK:       bb4:
; CHECK-NEXT:    [[ALLOCA2:%.*]] = phi ptr [ [[ALLOCA1]], [[BB3]] ], [ [[ALLOCA]], [[BB2]] ]
; CHECK-NEXT:    ret void
;
bb:
  br i1 %arg, label %bb1, label %bb2

bb1:
  call void @dummy()
  br label %bb2

bb2:
  %alloca = alloca [4 x [4 x i32]], align 8
  br i1 %arg, label %bb3, label %bb4

bb3:
  br label %bb4

bb4:
  call void @llvm.lifetime.start.p0(ptr %alloca)
  call void @llvm.lifetime.end.p0(ptr %alloca)
  ret void
}

; Because the alloca is in the entry block, it dominates all threaded blocks.
; No PHI node is required, and the lifetime markers can be safely preserved.
define void @widget_preserved(i1 %arg) {
; CHECK-LABEL: @widget_preserved(
; CHECK-NEXT:  bb:
; CHECK-NEXT:    [[ALLOCA:%.*]] = alloca [4 x [4 x i32]], align 8
; CHECK-NEXT:    br i1 [[ARG:%.*]], label [[BB3:%.*]], label [[BB4:%.*]]
; CHECK:       bb3:
; CHECK-NEXT:    call void @dummy()
; CHECK-NEXT:    br label [[BB4]]
; CHECK:       bb4:
; CHECK-NEXT:    call void @llvm.lifetime.start.p0(ptr [[ALLOCA]])
; CHECK-NEXT:    call void @llvm.lifetime.end.p0(ptr [[ALLOCA]])
; CHECK-NEXT:    ret void
;
bb:
  %alloca = alloca [4 x [4 x i32]], align 8
  br i1 %arg, label %bb1, label %bb2

bb1:
  call void @dummy()
  br label %bb2

bb2:
  br i1 %arg, label %bb3, label %bb4

bb3:
  br label %bb4

bb4:
  call void @llvm.lifetime.start.p0(ptr %alloca)
  call void @llvm.lifetime.end.p0(ptr %alloca)
  ret void
}

declare void @dummy()

attributes #0 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }