llvm/test/Analysis/GlobalsModRef/nonescaping-noalias.ll

; RUN: opt < %s -aa-pipeline=basic-aa,globals-aa -passes='require<globals-aa>,gvn' -S | FileCheck %s
;
; This tests the safe no-alias conclusions of GMR -- when there is
; a non-escaping global as one indentified underlying object and some pointer
; that would inherently have escaped any other function as the other underlying
; pointer of an alias query.

@g1 = internal global i32 0

define i32 @test1(ptr %param) {
; Ensure that we can fold a store to a load of a global across a store to
; a parameter when the global is non-escaping.
;
; CHECK-LABEL: @test1(
; CHECK: store i32 42, ptr @g1
; CHECK-NOT: load i32
; CHECK: ret i32 42
entry:
  store i32 42, ptr @g1
  store i32 7, ptr %param
  %v = load i32, ptr @g1
  ret i32 %v
}

@g1_tls = internal thread_local global i32 0

define i32 @test1_tls(ptr %param) {
; Ensure that we can fold a store to a load of a global across a store to
; a parameter when the global is non-escaping.
;
; CHECK-LABEL: define i32 @test1_tls(
; CHECK-SAME: ptr [[PARAM:%.*]]) {
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[P:%.*]] = call ptr @llvm.threadlocal.address.p0(ptr @g1_tls)
; CHECK-NEXT:    store i32 42, ptr [[P]], align 4
; CHECK-NEXT:    store i32 7, ptr [[PARAM]], align 4
; CHECK-NEXT:    ret i32 42
;
entry:
  %p = call ptr @llvm.threadlocal.address(ptr @g1_tls)
  store i32 42, ptr %p
  store i32 7, ptr %param
  %p2 = call ptr @llvm.threadlocal.address(ptr @g1_tls)
  %v = load i32, ptr %p2
  ret i32 %v
}

define ptr @test1_tls_noopt(ptr %coro, ptr %param) presplitcoroutine {
; CHECK-LABEL: define ptr @test1_tls_noopt(
; CHECK-SAME: ptr [[CORO:%.*]], ptr [[PARAM:%.*]]) #[[ATTR0:[0-9]+]] {
; CHECK-NEXT:  entry:
; CHECK-NEXT:    [[P:%.*]] = call ptr @llvm.threadlocal.address.p0(ptr @g1_tls)
; CHECK-NEXT:    store i32 42, ptr [[P]], align 4
; CHECK-NEXT:    [[TMP0:%.*]] = call i8 @llvm.coro.suspend(token none, i1 false)
; CHECK-NEXT:    switch i8 [[TMP0]], label [[SUSPEND:%.*]] [
; CHECK-NEXT:      i8 0, label [[RESUME:%.*]]
; CHECK-NEXT:      i8 1, label [[SUSPEND]]
; CHECK-NEXT:    ]
; CHECK:       resume:
; CHECK-NEXT:    [[P2:%.*]] = call ptr @llvm.threadlocal.address.p0(ptr @g1_tls)
; CHECK-NEXT:    [[V:%.*]] = load i32, ptr [[P2]], align 4
; CHECK-NEXT:    store i32 [[V]], ptr [[PARAM]], align 4
; CHECK-NEXT:    ret ptr [[CORO]]
; CHECK:       suspend:
; CHECK-NEXT:    [[TMP1:%.*]] = call i1 @llvm.coro.end(ptr [[CORO]], i1 false, token none)
; CHECK-NEXT:    ret ptr [[CORO]]
;
entry:
  %p = call ptr @llvm.threadlocal.address(ptr @g1_tls)
  store i32 42, ptr %p

  %0 = call i8 @llvm.coro.suspend(token none, i1 false)
  switch i8 %0, label %suspend [i8 0, label %resume
  i8 1, label %suspend]
resume:
  %p2 = call ptr @llvm.threadlocal.address(ptr @g1_tls)
  %v = load i32, ptr %p2
  store i32 %v, ptr %param, align 4
  ret ptr %coro

suspend:
  call i1 @llvm.coro.end(ptr %coro, i1 0, token none)
  ret ptr %coro
}

declare ptr @f()

define i32 @test2() {
; Ensure that we can fold a store to a load of a global across a store to
; the pointer returned by a function call. Since the global could not escape,
; this function cannot be returning its address.
;
; CHECK-LABEL: @test2(
; CHECK: store i32 42, ptr @g1
; CHECK-NOT: load i32
; CHECK: ret i32 42
entry:
  %ptr = call ptr @f() readnone
  store i32 42, ptr @g1
  store i32 7, ptr %ptr
  %v = load i32, ptr @g1
  ret i32 %v
}

@g2 = external global ptr

define i32 @test3() {
; Ensure that we can fold a store to a load of a global across a store to
; the pointer loaded from that global. Because the global does not escape, it
; cannot alias a pointer loaded out of a global.
;
; CHECK-LABEL: @test3(
; CHECK: store i32 42, ptr @g1
; CHECK: store i32 7, ptr
; CHECK-NOT: load i32
; CHECK: ret i32 42
entry:
  store i32 42, ptr @g1
  %ptr1 = load ptr, ptr @g2
  store i32 7, ptr %ptr1
  %v = load i32, ptr @g1
  ret i32 %v
}

@g3 = internal global i32 1
@g4 = internal global [10 x ptr] zeroinitializer

define i32 @test4(ptr %param, i32 %n, i1 %c1, i1 %c2, i1 %c3) {
; Ensure that we can fold a store to a load of a global across a store to
; the pointer loaded from that global even when the load is behind PHIs and
; selects, and there is a mixture of a load and another global or argument.
; Note that we can't eliminate the load here because it is used in a PHI and
; GVN doesn't try to do real DCE. The store is still forwarded by GVN though.
;
; CHECK-LABEL: @test4(
; CHECK: store i32 42, ptr @g1
; CHECK: store i32 7, ptr
; CHECK: ret i32 42
entry:
  %call = call ptr @f()
  store i32 42, ptr @g1
  %ptr1 = load ptr, ptr @g2
  %ptr2 = select i1 %c1, ptr %ptr1, ptr %param
  %ptr3 = select i1 %c3, ptr %ptr2, ptr @g3
  br label %loop

loop:
  %iv = phi i32 [ 0, %entry ], [ %inc, %loop ]
  %ptr = phi ptr [ %ptr3, %entry ], [ %ptr5, %loop ]
  store i32 7, ptr %ptr
  %ptr4 = load ptr, ptr getelementptr ([10 x ptr], ptr @g4, i32 0, i32 1)
  %ptr5 = select i1 %c2, ptr %ptr4, ptr %call
  %inc = add i32 %iv, 1
  %test = icmp slt i32 %inc, %n
  br i1 %test, label %loop, label %exit

exit:
  %v = load i32, ptr @g1
  ret i32 %v
}

define i32 @test5(ptr %param) {
; Ensure that we can fold a store to a load of a global across a store to
; a parameter that has been dereferenced when the global is non-escaping.
;
; CHECK-LABEL: @test5(
; CHECK: %p = load ptr
; CHECK: store i32 42, ptr @g1
; CHECK-NOT: load i32
; CHECK: ret i32 42
entry:
  %p = load ptr, ptr %param
  store i32 42, ptr @g1
  store i32 7, ptr %p
  %v = load i32, ptr @g1
  ret i32 %v
}

define i32 @test6(ptr %param) {
; Ensure that we can fold a store to a load of a global across a set of
; calls that cannot use in any way a non-escaping global.
;
; CHECK-LABEL: @test6(
; CHECK: store i32 42, ptr @g1
; CHECK-NOT: load i32
; CHECK: ret i32 42
entry:
  store i32 42, ptr @g1
  %1 = call ptr @_FortranAioBeginExternalFormattedOutput(ptr null, i64 3, ptr null, i32 6, ptr null, i32 2)
  %2 = call i1 @_FortranAioOutputAscii(ptr %1, ptr null, i64 4)
  %3 = call i32 @_FortranAioEndIoStatement(ptr %1)
  %v = load i32, ptr @g1
  ret i32 %v
}
declare ptr @_FortranAioBeginExternalFormattedOutput(ptr, i64, ptr, i32, ptr, i32) #0
declare zeroext i1 @_FortranAioOutputAscii(ptr, ptr, i64) #0
declare i32 @_FortranAioEndIoStatement(ptr) #0
attributes #0 = { nocallback nosync }