llvm/test/Transforms/LCSSA/lifetime-markers.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -passes=lcssa -S %s | FileCheck %s

; Lifetime markers must point directly to allocas. If an alloca is defined in
; a loop and a marker uses it outside the loop, LCSSA must drop all of the
; alloca's lifetime markers instead of rewriting one through a PHI.

define void @drop_lifetime_markers(i1 %repeat) {
; CHECK-LABEL: define void @drop_lifetime_markers(
; CHECK-SAME: i1 [[REPEAT:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    [[STORAGE:%.*]] = alloca i8, align 1
; CHECK-NEXT:    br i1 [[REPEAT]], label %[[LOOP]], label %[[EXIT:.*]]
; CHECK:       [[EXIT]]:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop
loop:
  %storage = alloca i8
  call void @llvm.lifetime.start.p0(ptr %storage)
  br i1 %repeat, label %loop, label %exit
exit:
  call void @llvm.lifetime.end.p0(ptr %storage)
  ret void
}

; If all lifetime markers stay inside the loop, preserve them even when another
; use of the alloca requires an LCSSA PHI.
define ptr @preserve_lifetime_markers(i1 %repeat) {
; CHECK-LABEL: define ptr @preserve_lifetime_markers(
; CHECK-SAME: i1 [[REPEAT:%.*]]) {
; CHECK-NEXT:  [[ENTRY:.*:]]
; CHECK-NEXT:    br label %[[LOOP:.*]]
; CHECK:       [[LOOP]]:
; CHECK-NEXT:    [[STORAGE:%.*]] = alloca i8, align 1
; CHECK-NEXT:    call void @llvm.lifetime.start.p0(ptr [[STORAGE]])
; CHECK-NEXT:    call void @llvm.lifetime.end.p0(ptr [[STORAGE]])
; CHECK-NEXT:    br i1 [[REPEAT]], label %[[LOOP]], label %[[EXIT:.*]]
; CHECK:       [[EXIT]]:
; CHECK-NEXT:    [[STORAGE_LCSSA:%.*]] = phi ptr [ [[STORAGE]], %[[LOOP]] ]
; CHECK-NEXT:    ret ptr [[STORAGE_LCSSA]]
;
entry:
  br label %loop
loop:
  %storage = alloca i8
  call void @llvm.lifetime.start.p0(ptr %storage)
  call void @llvm.lifetime.end.p0(ptr %storage)
  br i1 %repeat, label %loop, label %exit
exit:
  ret ptr %storage
}