mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-24 06:30:19 +00:00
66b380b6b6
Even loads/stores that have a stronger ordering than monotonic can be safe. The rule is no release-acquire pair on the path from the QueryInst, assuming that the QueryInst is not atomic itself. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216771 91177308-0d34-0410-b5e6-96231b3b80d8
179 lines
4.6 KiB
LLVM
179 lines
4.6 KiB
LLVM
; RUN: opt -basicaa -dse -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"
|
|
|
|
; Sanity tests for atomic stores.
|
|
; Note that it turns out essentially every transformation DSE does is legal on
|
|
; atomic ops, just some transformations are not allowed across release-acquire pairs.
|
|
|
|
@x = common global i32 0, align 4
|
|
@y = common global i32 0, align 4
|
|
|
|
declare void @randomop(i32*)
|
|
|
|
; DSE across unordered store (allowed)
|
|
define void @test1() {
|
|
; CHECK-LABEL: test1
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
store atomic i32 0, i32* @y unordered, align 4
|
|
store i32 1, i32* @x
|
|
ret void
|
|
}
|
|
|
|
; DSE across seq_cst load (allowed)
|
|
define i32 @test2() {
|
|
; CHECK-LABEL: test2
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
%x = load atomic i32* @y seq_cst, align 4
|
|
store i32 1, i32* @x
|
|
ret i32 %x
|
|
}
|
|
|
|
; DSE across seq_cst store (allowed)
|
|
define void @test3() {
|
|
; CHECK-LABEL: test3
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store atomic i32 2
|
|
store i32 0, i32* @x
|
|
store atomic i32 2, i32* @y seq_cst, align 4
|
|
store i32 1, i32* @x
|
|
ret void
|
|
}
|
|
|
|
; DSE remove unordered store (allowed)
|
|
define void @test4() {
|
|
; CHECK-LABEL: test4
|
|
; CHECK-NOT: store atomic
|
|
; CHECK: store i32 1
|
|
store atomic i32 0, i32* @x unordered, align 4
|
|
store i32 1, i32* @x
|
|
ret void
|
|
}
|
|
|
|
; DSE unordered store overwriting non-atomic store (allowed)
|
|
define void @test5() {
|
|
; CHECK-LABEL: test5
|
|
; CHECK: store atomic i32 1
|
|
store i32 0, i32* @x
|
|
store atomic i32 1, i32* @x unordered, align 4
|
|
ret void
|
|
}
|
|
|
|
; DSE no-op unordered atomic store (allowed)
|
|
define void @test6() {
|
|
; CHECK-LABEL: test6
|
|
; CHECK-NOT: store
|
|
; CHECK: ret void
|
|
%x = load atomic i32* @x unordered, align 4
|
|
store atomic i32 %x, i32* @x unordered, align 4
|
|
ret void
|
|
}
|
|
|
|
; DSE seq_cst store (be conservative; DSE doesn't have infrastructure
|
|
; to reason about atomic operations).
|
|
define void @test7() {
|
|
; CHECK-LABEL: test7
|
|
; CHECK: store atomic
|
|
%a = alloca i32
|
|
store atomic i32 0, i32* %a seq_cst, align 4
|
|
ret void
|
|
}
|
|
|
|
; DSE and seq_cst load (be conservative; DSE doesn't have infrastructure
|
|
; to reason about atomic operations).
|
|
define i32 @test8() {
|
|
; CHECK-LABEL: test8
|
|
; CHECK: store
|
|
; CHECK: load atomic
|
|
%a = alloca i32
|
|
call void @randomop(i32* %a)
|
|
store i32 0, i32* %a, align 4
|
|
%x = load atomic i32* @x seq_cst, align 4
|
|
ret i32 %x
|
|
}
|
|
|
|
; DSE across monotonic load (allowed as long as the eliminated store isUnordered)
|
|
define i32 @test9() {
|
|
; CHECK-LABEL: test9
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
%x = load atomic i32* @y monotonic, align 4
|
|
store i32 1, i32* @x
|
|
ret i32 %x
|
|
}
|
|
|
|
; DSE across monotonic store (allowed as long as the eliminated store isUnordered)
|
|
define void @test10() {
|
|
; CHECK-LABEL: test10
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
store atomic i32 42, i32* @y monotonic, align 4
|
|
store i32 1, i32* @x
|
|
ret void
|
|
}
|
|
|
|
; DSE across monotonic load (forbidden since the eliminated store is atomic)
|
|
define i32 @test11() {
|
|
; CHECK-LABEL: test11
|
|
; CHECK: store atomic i32 0
|
|
; CHECK: store atomic i32 1
|
|
store atomic i32 0, i32* @x monotonic, align 4
|
|
%x = load atomic i32* @y monotonic, align 4
|
|
store atomic i32 1, i32* @x monotonic, align 4
|
|
ret i32 %x
|
|
}
|
|
|
|
; DSE across monotonic store (forbidden since the eliminated store is atomic)
|
|
define void @test12() {
|
|
; CHECK-LABEL: test12
|
|
; CHECK: store atomic i32 0
|
|
; CHECK: store atomic i32 1
|
|
store atomic i32 0, i32* @x monotonic, align 4
|
|
store atomic i32 42, i32* @y monotonic, align 4
|
|
store atomic i32 1, i32* @x monotonic, align 4
|
|
ret void
|
|
}
|
|
|
|
; DSE is allowed across a pair of an atomic read and then write.
|
|
define i32 @test13() {
|
|
; CHECK-LABEL: test13
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
%x = load atomic i32* @y seq_cst, align 4
|
|
store atomic i32 %x, i32* @y seq_cst, align 4
|
|
store i32 1, i32* @x
|
|
ret i32 %x
|
|
}
|
|
|
|
; Same if it is acquire-release instead of seq_cst/seq_cst
|
|
define i32 @test14() {
|
|
; CHECK-LABEL: test14
|
|
; CHECK-NOT: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
%x = load atomic i32* @y acquire, align 4
|
|
store atomic i32 %x, i32* @y release, align 4
|
|
store i32 1, i32* @x
|
|
ret i32 %x
|
|
}
|
|
|
|
; But DSE is not allowed across a release-acquire pair.
|
|
define i32 @test15() {
|
|
; CHECK-LABEL: test15
|
|
; CHECK: store i32 0
|
|
; CHECK: store i32 1
|
|
store i32 0, i32* @x
|
|
store atomic i32 0, i32* @y release, align 4
|
|
%x = load atomic i32* @y acquire, align 4
|
|
store i32 1, i32* @x
|
|
ret i32 %x
|
|
}
|