f932646bf6
Branch weight metadata can overflow when folding large branch weights. Updated branch weights to uint64_t, added check for overflow, and then set branch weights using setFittedBranchWeights to ensure branch weight metadata is not lost.
52 lines
1.8 KiB
LLVM
52 lines
1.8 KiB
LLVM
; RUN: opt < %s -passes=simplifycfg -S | FileCheck %s
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; Ensure branch weight does not overflow when folding block 3 into block 0.
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; This IR test is reduced from an optimization that occurs during the Jump
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; Threading pass, which creates a branch prediction of 0% and 100%. This is
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; reduced in SimplifyCFG into the IR shown in the
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; switch-branch-weight-overflow.ll test.
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define void @foo(ptr %Overflow) {
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; CHECK-LABEL: define void @foo
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; CHECK: br i1 {{.*}}, label %[[BB2:.*]], label %[[BB3:.*]], !prof [[PROF0:![0-9]+]]
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%1 = extractvalue { i32, i1 } zeroinitializer, 0
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%2 = icmp eq i32 %1, 0
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br i1 %2, label %6, label %3
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3: ; preds = %0
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%4 = icmp eq i32 %1, 1
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br i1 %4, label %5, label %6, !prof !0
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5: ; preds = %3
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store i32 0, ptr %Overflow, align 4
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br label %6
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6: ; preds = %5, %3, %0
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ret void
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}
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; Ensure that the branch weight from folding branch 0 and the default branch
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; does not overflow. This IR test is reduced from the IR above.
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define void @bar(ptr %Overflow) {
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; CHECK-LABEL: define void @bar
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; CHECK: br i1 {{.*}}, label %[[BB2:.*]], label %[[BB3:.*]], !prof [[PROF1:![0-9]+]]
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%1 = extractvalue { i32, i1 } zeroinitializer, 0
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switch i32 %1, label %3 [
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i32 0, label %3
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i32 1, label %2
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], !prof !1
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2: ; preds = %0
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store i32 0, ptr %Overflow, align 4
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br label %3
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3: ; preds = %0, %0, %2
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ret void
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}
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; CHECK: [[PROF0]] = !{!"branch_weights", i32 0, i32 -2147483648}
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; CHECK: [[PROF1]] = !{!"branch_weights", i32 500, i32 -2147483648}
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!0 = !{!"branch_weights", !"expected", i32 0, i32 -2147483648}
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!1 = !{!"branch_weights", !"expected", i32 -2147483648, i32 -2147483648, i32 1000}
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