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.
57 lines
2.1 KiB
LLVM
57 lines
2.1 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
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; RUN: opt -S -passes="jump-threading" < %s 2>&1 | FileCheck %s
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declare void @foobar()
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define i32 @func0(i32 %a0, i32 %a1) !prof !0 {
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; CHECK-LABEL: @func0(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: [[CMP0:%.*]] = icmp ne i32 [[A0:%.*]], 0
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; CHECK-NEXT: [[CX:%.*]] = icmp eq i32 [[A0]], 42
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; CHECK-NEXT: br i1 [[CMP0]], label [[BB_JOIN:%.*]], label [[TEST2:%.*]], !prof [[PROF1:![0-9]+]]
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; CHECK: test2:
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; CHECK-NEXT: [[CMP1:%.*]] = icmp ne i32 [[A1:%.*]], 0
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; CHECK-NEXT: br i1 [[CMP1]], label [[BB_JOIN_THREAD:%.*]], label [[TEST2_FALSE:%.*]], !prof [[PROF2:![0-9]+]]
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; CHECK: test2_false:
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; CHECK-NEXT: call void @foobar()
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; CHECK-NEXT: br label [[TMP0:%.*]]
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; CHECK: bb_join:
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; CHECK-NEXT: [[C:%.*]] = phi i1 [ [[CX]], [[ENTRY:%.*]] ]
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; CHECK-NEXT: [[COND_FR:%.*]] = freeze i1 [[C]]
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; CHECK-NEXT: br i1 [[COND_FR]], label [[BB_JOIN_THREAD]], label [[TMP0]], !prof [[PROF3:![0-9]+]]
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; CHECK: bb_join.thread:
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; CHECK-NEXT: br label [[TMP0]]
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; CHECK: 0:
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; CHECK-NEXT: [[TMP1:%.*]] = phi i32 [ 42, [[BB_JOIN_THREAD]] ], [ 7, [[BB_JOIN]] ], [ 7, [[TEST2_FALSE]] ]
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; CHECK-NEXT: ret i32 [[TMP1]]
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;
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entry:
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%cmp0 = icmp ne i32 %a0, 0
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%cx = icmp eq i32 %a0, 42
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br i1 %cmp0, label %bb_join, label %test2, !prof !1
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test2:
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%cmp1 = icmp ne i32 %a1, 0
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br i1 %cmp1, label %bb_join, label %test2_false, !prof !2
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test2_false:
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call void @foobar()
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br label %bb_join
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bb_join:
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%c = phi i1 [%cx, %entry], [true, %test2], [%cx, %test2_false]
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%val = select i1 %c, i32 42, i32 7, !prof !3
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ret i32 %val
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}
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!0 = !{!"function_entry_count", i64 1000}
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!1 = !{!"branch_weights", i32 400, i32 600}
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!2 = !{!"branch_weights", i32 300, i32 300}
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!3 = !{!"branch_weights", i32 500, i32 500}
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;.
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; CHECK: [[META0:![0-9]+]] = !{!"function_entry_count", i64 1000}
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; CHECK: [[PROF1]] = !{!"branch_weights", i32 400, i32 600}
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; CHECK: [[PROF2]] = !{!"branch_weights", i32 300, i32 300}
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; CHECK: [[PROF3]] = !{!"branch_weights", i32 613566756, i32 1533916892}
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;.
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