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https://github.com/c64scene-ar/llvm-6502.git
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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
132 lines
3.1 KiB
LLVM
132 lines
3.1 KiB
LLVM
; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
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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"
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target triple = "x86_64-apple-macosx10.7.0"
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@x = common global i32 0, align 4
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@y = common global i32 0, align 4
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; GVN across unordered store (allowed)
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define i32 @test1() nounwind uwtable ssp {
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; CHECK-LABEL: test1
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; CHECK: add i32 %x, %x
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entry:
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%x = load i32* @y
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store atomic i32 %x, i32* @x unordered, align 4
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%y = load i32* @y
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%z = add i32 %x, %y
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ret i32 %z
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}
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; GVN across seq_cst store (allowed)
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define i32 @test2() nounwind uwtable ssp {
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; CHECK-LABEL: test2
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; CHECK: add i32 %x, %x
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entry:
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%x = load i32* @y
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store atomic i32 %x, i32* @x seq_cst, align 4
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%y = load i32* @y
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%z = add i32 %x, %y
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ret i32 %z
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}
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; GVN across unordered load (allowed)
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define i32 @test3() nounwind uwtable ssp {
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; CHECK-LABEL: test3
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; CHECK: add i32 %x, %x
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entry:
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%x = load i32* @y
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%y = load atomic i32* @x unordered, align 4
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%z = load i32* @y
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%a = add i32 %x, %z
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%b = add i32 %y, %a
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ret i32 %b
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}
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; GVN across acquire load (allowed as the original load was not atomic)
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define i32 @test4() nounwind uwtable ssp {
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; CHECK-LABEL: test4
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; CHECK: load atomic i32* @x
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; CHECK-NOT: load i32* @y
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entry:
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%x = load i32* @y
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%y = load atomic i32* @x seq_cst, align 4
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%x2 = load i32* @y
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%x3 = add i32 %x, %x2
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%y2 = add i32 %y, %x3
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ret i32 %y2
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}
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; GVN load to unordered load (allowed)
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define i32 @test5() nounwind uwtable ssp {
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; CHECK-LABEL: test5
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; CHECK: add i32 %x, %x
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entry:
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%x = load atomic i32* @x unordered, align 4
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%y = load i32* @x
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%z = add i32 %x, %y
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ret i32 %z
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}
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; GVN unordered load to load (unordered load must not be removed)
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define i32 @test6() nounwind uwtable ssp {
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; CHECK-LABEL: test6
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; CHECK: load atomic i32* @x unordered
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entry:
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%x = load i32* @x
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%x2 = load atomic i32* @x unordered, align 4
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%x3 = add i32 %x, %x2
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ret i32 %x3
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}
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; GVN across release-acquire pair (forbidden)
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define i32 @test7() nounwind uwtable ssp {
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; CHECK-LABEL: test7
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; CHECK: add i32 %x, %y
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entry:
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%x = load i32* @y
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store atomic i32 %x, i32* @x release, align 4
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%w = load atomic i32* @x acquire, align 4
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%y = load i32* @y
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%z = add i32 %x, %y
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ret i32 %z
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}
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; GVN across acquire-release pair (allowed)
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define i32 @test8() nounwind uwtable ssp {
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; CHECK-LABEL: test8
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; CHECK: add i32 %x, %x
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entry:
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%x = load i32* @y
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%w = load atomic i32* @x acquire, align 4
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store atomic i32 %x, i32* @x release, align 4
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%y = load i32* @y
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%z = add i32 %x, %y
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ret i32 %z
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}
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; GVN across monotonic store (allowed)
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define i32 @test9() nounwind uwtable ssp {
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; CHECK-LABEL: test9
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; CHECK: add i32 %x, %x
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entry:
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%x = load i32* @y
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store atomic i32 %x, i32* @x monotonic, align 4
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%y = load i32* @y
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%z = add i32 %x, %y
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ret i32 %z
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}
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; GVN of an unordered across monotonic load (not allowed)
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define i32 @test10() nounwind uwtable ssp {
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; CHECK-LABEL: test10
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; CHECK: add i32 %x, %y
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entry:
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%x = load atomic i32* @y unordered, align 4
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%clobber = load atomic i32* @x monotonic, align 4
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%y = load atomic i32* @y monotonic, align 4
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%z = add i32 %x, %y
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ret i32 %z
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}
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