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https://github.com/c64scene-ar/llvm-6502.git
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51f40a725b
probability wouldn't be considered "hot" in some weird loop structures or other compounding probability patterns. This makes it much harder to confuse, but isn't really a principled fix. I'd actually like it if we could model a zero probability, as it would make this much easier to reason about. Suggestions for how to do this better are welcome. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147142 91177308-0d34-0410-b5e6-96231b3b80d8
80 lines
1.9 KiB
LLVM
80 lines
1.9 KiB
LLVM
; Test the static branch probability heuristics for no-return functions.
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; RUN: opt < %s -analyze -branch-prob | FileCheck %s
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declare void @abort() noreturn
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define i32 @test1(i32 %a, i32 %b) {
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; CHECK: Printing analysis {{.*}} for function 'test1'
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entry:
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%cond = icmp eq i32 %a, 42
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br i1 %cond, label %exit, label %abort
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; CHECK: edge entry -> exit probability is 1048575 / 1048576
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; CHECK: edge entry -> abort probability is 1 / 1048576
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abort:
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call void @abort() noreturn
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unreachable
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exit:
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ret i32 %b
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}
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define i32 @test2(i32 %a, i32 %b) {
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; CHECK: Printing analysis {{.*}} for function 'test2'
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entry:
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switch i32 %a, label %exit [i32 1, label %case_a
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i32 2, label %case_b
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i32 3, label %case_c
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i32 4, label %case_d]
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; CHECK: edge entry -> exit probability is 1048575 / 1048579
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; CHECK: edge entry -> case_a probability is 1 / 1048579
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; CHECK: edge entry -> case_b probability is 1 / 1048579
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; CHECK: edge entry -> case_c probability is 1 / 1048579
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; CHECK: edge entry -> case_d probability is 1 / 1048579
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case_a:
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br label %case_b
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case_b:
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br label %case_c
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case_c:
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br label %case_d
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case_d:
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call void @abort() noreturn
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unreachable
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exit:
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ret i32 %b
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}
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define i32 @test3(i32 %a, i32 %b) {
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; CHECK: Printing analysis {{.*}} for function 'test3'
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; Make sure we unify across multiple conditional branches.
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entry:
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%cond1 = icmp eq i32 %a, 42
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br i1 %cond1, label %exit, label %dom
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; CHECK: edge entry -> exit probability is 1048575 / 1048576
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; CHECK: edge entry -> dom probability is 1 / 1048576
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dom:
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%cond2 = icmp ult i32 %a, 42
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br i1 %cond2, label %idom1, label %idom2
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; CHECK: edge dom -> idom1 probability is 1 / 2
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; CHECK: edge dom -> idom2 probability is 1 / 2
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idom1:
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br label %abort
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idom2:
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br label %abort
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abort:
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call void @abort() noreturn
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unreachable
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exit:
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ret i32 %b
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}
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