e3cf80c5c1
BlockFrequencyInfo calculates block frequencies as Scaled64 numbers but as a last step converts them to unsigned 64bit integers (`BlockFrequency`). This improves the factors picked for this conversion so that: * Avoid big numbers close to UINT64_MAX to avoid users overflowing/saturating when adding multiply frequencies together or when multiplying with integers. This leaves the topmost 10 bits unused to allow for some room. * Spread the difference between hottest/coldest block as much as possible to increase precision. * If the hot/cold spread cannot be represented loose precision at the lower end, but keep the frequencies at the upper end for hot blocks differentiable.
44 lines
851 B
LLVM
44 lines
851 B
LLVM
; RUN: opt -S -passes=jump-threading %s | FileCheck %s
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; Test if edge weights are properly updated after jump threading.
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; CHECK: !2 = !{!"branch_weights", i32 1561806291, i32 585677357}
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define void @foo(i32 %n) !prof !0 {
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entry:
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%cmp = icmp sgt i32 %n, 10
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br i1 %cmp, label %if.then.1, label %if.else.1, !prof !1
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if.then.1:
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tail call void @a()
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br label %if.cond
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if.else.1:
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tail call void @b()
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br label %if.cond
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if.cond:
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%cmp1 = icmp sgt i32 %n, 5
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br i1 %cmp1, label %if.then.2, label %if.else.2, !prof !2
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if.then.2:
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tail call void @c()
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br label %if.end
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if.else.2:
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tail call void @d()
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br label %if.end
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if.end:
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ret void
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}
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declare void @a()
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declare void @b()
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declare void @c()
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declare void @d()
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!0 = !{!"function_entry_count", i64 1}
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!1 = !{!"branch_weights", i32 10, i32 5}
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!2 = !{!"branch_weights", i32 10, i32 1}
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