third_party/LLVM/test/Transforms/GVN/atomic.ll

; RUN: opt -basicaa -gvn -S < %s | FileCheck %s

target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-macosx10.7.0"

@x = common global i32 0, align 4
@y = common global i32 0, align 4

; GVN across unordered store (allowed)
define i32 @test1() nounwind uwtable ssp {
; CHECK: test1
; CHECK: add i32 %x, %x
entry:
  %x = load i32* @y
  store atomic i32 %x, i32* @x unordered, align 4
  %y = load i32* @y
  %z = add i32 %x, %y
  ret i32 %z
}

; GVN across seq_cst store (allowed in theory; not implemented ATM)
define i32 @test2() nounwind uwtable ssp {
; CHECK: test2
; CHECK: add i32 %x, %y
entry:
  %x = load i32* @y
  store atomic i32 %x, i32* @x seq_cst, align 4
  %y = load i32* @y
  %z = add i32 %x, %y
  ret i32 %z
}

; GVN across unordered load (allowed)
define i32 @test3() nounwind uwtable ssp {
; CHECK: test3
; CHECK: add i32 %x, %x
entry:
  %x = load i32* @y
  %y = load atomic i32* @x unordered, align 4
  %z = load i32* @y
  %a = add i32 %x, %z
  %b = add i32 %y, %a
  ret i32 %b
}

; GVN across acquire load (load after atomic load must not be removed)
define i32 @test4() nounwind uwtable ssp {
; CHECK: test4
; CHECK: load atomic i32* @x
; CHECK: load i32* @y
entry:
  %x = load i32* @y
  %y = load atomic i32* @x seq_cst, align 4
  %x2 = load i32* @y
  %x3 = add i32 %x, %x2
  %y2 = add i32 %y, %x3
  ret i32 %y2
}

; GVN load to unordered load (allowed)
define i32 @test5() nounwind uwtable ssp {
; CHECK: test5
; CHECK: add i32 %x, %x
entry:
  %x = load atomic i32* @x unordered, align 4
  %y = load i32* @x
  %z = add i32 %x, %y
  ret i32 %z
}

; GVN unordered load to load (unordered load must not be removed)
define i32 @test6() nounwind uwtable ssp {
; CHECK: test6
; CHECK: load atomic i32* @x unordered
entry:
  %x = load i32* @x
  %x2 = load atomic i32* @x unordered, align 4
  %x3 = add i32 %x, %x2
  ret i32 %x3
}