ecb4171dcb
In some case, like in the added test case, we can reach selectInterleaveCount with loops that actually have a cost of 0. Unfortunately a loop cost of 0 is also used to communicate that the cost has not been computed yet. To resolve the crash, bail out if the cost remains zero after computing it. This seems like the best option, as there are multiple code paths that return a cost of 0 to force a computation in selectInterleaveCount. Computing the cost at multiple places up front there would unnecessarily complicate the logic. Fixes #54413.
51 lines
1.8 KiB
LLVM
51 lines
1.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -passes='loop(indvars),loop-vectorize' -S %s | FileCheck %s
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target triple = "x86_64-unknown-linux-gnu"
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; After indvars, the backedge taken count for %loop2 becomes 1, but SCEV
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; retains the cached original BTC, as the loop is in dead code. Make sure
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; LV does not crash when trying to select an interleave count for a loop with zero cost.
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define void @pr54413(i64* %ptr.base) {
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; CHECK-LABEL: @pr54413(
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; CHECK-NEXT: entry:
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; CHECK-NEXT: br label [[LOOP1:%.*]]
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; CHECK: loop1:
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; CHECK-NEXT: br i1 true, label [[LOOP1_LATCH:%.*]], label [[LOOP2_PREHEADER:%.*]]
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; CHECK: loop2.preheader:
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; CHECK-NEXT: br label [[LOOP2:%.*]]
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; CHECK: loop2:
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; CHECK-NEXT: [[PTR:%.*]] = phi i64* [ [[PTR_BASE:%.*]], [[LOOP2_PREHEADER]] ], [ [[PTR_NEXT:%.*]], [[LOOP2]] ]
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; CHECK-NEXT: [[PTR_NEXT]] = getelementptr inbounds i64, i64* [[PTR]], i64 1
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; CHECK-NEXT: br i1 true, label [[LOOP2_EXIT:%.*]], label [[LOOP2]]
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; CHECK: loop2.exit:
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; CHECK-NEXT: [[PTR_NEXT_LCSSA:%.*]] = phi i64* [ [[PTR_NEXT]], [[LOOP2]] ]
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; CHECK-NEXT: br label [[LOOP1_LATCH]]
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; CHECK: loop1.latch:
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; CHECK-NEXT: br label [[LOOP1]]
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;
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entry:
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br label %loop1
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loop1:
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br i1 true, label %loop1.latch, label %loop2.preheader
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loop2.preheader:
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br label %loop2
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loop2:
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%iv = phi i64 [ 0, %loop2.preheader ], [ %iv.next, %loop2 ]
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%ptr = phi i64* [ %ptr.base, %loop2.preheader ], [ %ptr.next, %loop2 ]
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%iv.next = add nuw nsw i64 %iv, 1
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%ptr.next = getelementptr inbounds i64, i64* %ptr, i64 1
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%cmp = icmp eq i64 %iv, 1024
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br i1 %cmp, label %loop2.exit, label %loop2
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loop2.exit:
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%ptr.next.lcssa = phi i64* [ %ptr.next, %loop2 ]
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br label %loop1.latch
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loop1.latch:
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br label %loop1
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}
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