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.
89 lines
2.5 KiB
LLVM
89 lines
2.5 KiB
LLVM
; RUN: llc -O2 -ppc-reduce-cr-logicals -print-machine-bfi -o - %s 2>&1 | FileCheck %s
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target datalayout = "e-m:e-i64:64-n32:64"
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target triple = "powerpc64le-grtev4-linux-gnu"
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; First block frequency info
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;CHECK: block-frequency-info: loop_test
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;CHECK-NEXT: - BB0[entry]: float = 1.0, int = {{.*}}
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;CHECK-NEXT: - BB1[for.check]: float = 2.6667, int = {{.*}}
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;CHECK-NEXT: - BB2[test1]: float = 1.6667, int = {{.*}}
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;CHECK-NEXT: - BB3[optional1]: float = 0.625, int = {{.*}}
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;CHECK: block-frequency-info: loop_test
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;CHECK: block-frequency-info: loop_test
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;CHECK: block-frequency-info: loop_test
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; Last block frequency info
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;CHECK: block-frequency-info: loop_test
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;CHECK-NEXT: - BB0[entry]: float = 1.0, int = {{.*}}
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;CHECK-NEXT: - BB1[for.check]: float = 2.6667, int = {{.*}}
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;CHECK-NEXT: - BB2[for.check]: float = 2.1667, int = {{.*}}
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;CHECK-NEXT: - BB3[test1]: float = 1.6667, int = {{.*}}
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;CHECK-NEXT: - BB4[optional1]: float = 0.625, int = {{.*}}
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define void @loop_test(ptr %tags, i32 %count) {
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entry:
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br label %for.check
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for.check:
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%count.loop = phi i32 [%count, %entry], [%count.sub, %for.latch]
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%done.count = icmp ugt i32 %count.loop, 0
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%tag_ptr = getelementptr inbounds i32, ptr %tags, i32 %count
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%tag = load i32, ptr %tag_ptr
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%done.tag = icmp eq i32 %tag, 0
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%done = and i1 %done.count, %done.tag
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br i1 %done, label %test1, label %exit, !prof !1
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test1:
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%tagbit1 = and i32 %tag, 1
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%tagbit1eq0 = icmp eq i32 %tagbit1, 0
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br i1 %tagbit1eq0, label %test2, label %optional1, !prof !1
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optional1:
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call void @a()
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call void @a()
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call void @a()
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call void @a()
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br label %test2
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test2:
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%tagbit2 = and i32 %tag, 2
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%tagbit2eq0 = icmp eq i32 %tagbit2, 0
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br i1 %tagbit2eq0, label %test3, label %optional2, !prof !1
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optional2:
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call void @b()
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call void @b()
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call void @b()
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call void @b()
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br label %test3
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test3:
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%tagbit3 = and i32 %tag, 4
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%tagbit3eq0 = icmp eq i32 %tagbit3, 0
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br i1 %tagbit3eq0, label %test4, label %optional3, !prof !1
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optional3:
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call void @c()
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call void @c()
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call void @c()
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call void @c()
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br label %test4
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test4:
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%tagbit4 = and i32 %tag, 8
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%tagbit4eq0 = icmp eq i32 %tagbit4, 0
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br i1 %tagbit4eq0, label %for.latch, label %optional4, !prof !1
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optional4:
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call void @d()
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call void @d()
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call void @d()
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call void @d()
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br label %for.latch
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for.latch:
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%count.sub = sub i32 %count.loop, 1
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br label %for.check
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exit:
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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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!1 = !{!"branch_weights", i32 5, i32 3}
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