137 lines
3.3 KiB
LLVM
137 lines
3.3 KiB
LLVM
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; Test if the !invariant.load metadata is maintained by GVN.
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; RUN: opt -basic-aa -gvn -S < %s | FileCheck %s
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define i32 @test1(i32* nocapture %p, i8* nocapture %q) {
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; CHECK-LABEL: test1
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; CHECK: %x = load i32, i32* %p, align 4, !invariant.load !0
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; CHECK-NOT: %y = load
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entry:
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%x = load i32, i32* %p, align 4, !invariant.load !0
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%conv = trunc i32 %x to i8
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store i8 %conv, i8* %q, align 1
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%y = load i32, i32* %p, align 4, !invariant.load !0
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%add = add i32 %y, 1
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ret i32 %add
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}
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define i32 @test2(i32* nocapture %p, i8* nocapture %q) {
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; CHECK-LABEL: test2
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; CHECK-NOT: !invariant.load
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; CHECK-NOT: %y = load
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entry:
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%x = load i32, i32* %p, align 4
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%conv = trunc i32 %x to i8
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store i8 %conv, i8* %q, align 1
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%y = load i32, i32* %p, align 4, !invariant.load !0
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%add = add i32 %y, 1
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ret i32 %add
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}
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; With the invariant.load metadata, what would otherwise
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; be a case for PRE becomes a full redundancy.
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define i32 @test3(i1 %cnd, i32* %p, i32* %q) {
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; CHECK-LABEL: test3
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; CHECK-NOT: load
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entry:
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%v1 = load i32, i32* %p
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br i1 %cnd, label %bb1, label %bb2
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bb1:
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store i32 5, i32* %q
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br label %bb2
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bb2:
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%v2 = load i32, i32* %p, !invariant.load !0
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%res = sub i32 %v1, %v2
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ret i32 %res
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}
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; This test is here to document a case which doesn't optimize
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; as well as it could.
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define i32 @test4(i1 %cnd, i32* %p, i32* %q) {
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; CHECK-LABEL: test4
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; %v2 is redundant, but GVN currently doesn't catch that
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entry:
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%v1 = load i32, i32* %p, !invariant.load !0
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br i1 %cnd, label %bb1, label %bb2
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bb1:
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store i32 5, i32* %q
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br label %bb2
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bb2:
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%v2 = load i32, i32* %p
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%res = sub i32 %v1, %v2
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ret i32 %res
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}
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; Checks that we return the mustalias store as a def
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; so that it contributes to value forwarding. Note
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; that we could and should remove the store too.
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define i32 @test5(i1 %cnd, i32* %p) {
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; CHECK-LABEL: test5
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; CHECK-LABEL: entry:
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; CHECK-NEXT: store i32 5, i32* %p
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; CHECK-NEXT: ret i32 5
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entry:
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%v1 = load i32, i32* %p, !invariant.load !0
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store i32 5, i32* %p ;; must alias store, want to exploit
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%v2 = load i32, i32* %p, !invariant.load !0
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ret i32 %v2
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}
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declare void @foo()
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; Clobbering (mayalias) stores, even in function calls, can be ignored
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define i32 @test6(i1 %cnd, i32* %p) {
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; CHECK-LABEL: test6
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; CHECK-LABEL: entry:
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; CHECK-NEXT: @foo
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; CHECK-NEXT: ret i32 0
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entry:
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%v1 = load i32, i32* %p, !invariant.load !0
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call void @foo()
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%v2 = load i32, i32* %p, !invariant.load !0
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%res = sub i32 %v1, %v2
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ret i32 %res
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}
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declare noalias i32* @bar(...)
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; Same as previous, but a function with a noalias result (since they're handled
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; differently in MDA)
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define i32 @test7(i1 %cnd, i32* %p) {
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; CHECK-LABEL: test7
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; CHECK-LABEL: entry:
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; CHECK-NEXT: @bar
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; CHECK-NEXT: ret i32 0
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entry:
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%v1 = load i32, i32* %p, !invariant.load !0
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call i32* (...) @bar(i32* %p)
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%v2 = load i32, i32* %p, !invariant.load !0
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%res = sub i32 %v1, %v2
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ret i32 %res
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}
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define i32 @test8(i1 %cnd, i32* %p) {
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; CHECK-LABEL: test8
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; CHECK: @bar
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; CHECK: load i32, i32* %p2, align 4, !invariant.load
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; CHECK: br label %merge
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entry:
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%v1 = load i32, i32* %p, !invariant.load !0
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br i1 %cnd, label %taken, label %merge
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taken:
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%p2 = call i32* (...) @bar(i32* %p)
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br label %merge
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merge:
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%p3 = phi i32* [%p, %entry], [%p2, %taken]
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%v2 = load i32, i32* %p3, !invariant.load !0
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%res = sub i32 %v1, %v2
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ret i32 %res
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}
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!0 = !{ }
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