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6fdd7c575a
This patch fixes a problem that occurs in LowerSwitch when a switch statement has a PHI node as its condition, and the PHI node only has two incoming blocks, and one of those incoming blocks is through an unreachable default in the switch statement. When this condition occurs, LowerSwitch holds a pointer to the condition value, but removes the switch block as a predecessor of the PHI block, causing the PHI node to be replaced. LowerSwitch then tries to use its stale pointer to the original condition value, causing a crash. Differential Revision: https://reviews.llvm.org/D62560 llvm-svn: 362427
37 lines
1.0 KiB
LLVM
37 lines
1.0 KiB
LLVM
; RUN: opt < %s -lowerswitch -S | FileCheck %s
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; This test verifies -lowerswitch does not crash when an removing an
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; unreachable default branch causes a PHI node used as the switch
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; condition to be erased.
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define void @f() local_unnamed_addr {
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entry:
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br label %sw.epilog
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sw.epilog: ; preds = %sw.epilog.outer, %for.body
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%i = phi i32 [ undef, %for.body ], [ 0, %entry ]
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br i1 undef, label %for.body, label %for.end
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for.body: ; preds = %sw.epilog
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switch i32 %i, label %sw.epilog [
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i32 0, label %sw.epilog.outer.backedge.loopexit
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i32 1, label %sw.epilog.outer.backedge
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]
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sw.epilog.outer.backedge.loopexit: ; preds = %for.body
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br label %for.end
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sw.epilog.outer.backedge: ; preds = %for.body
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unreachable
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for.end: ; preds = %sw.epilog
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ret void
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}
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; The phi and the switch should both be eliminated.
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; CHECK: @f()
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; CHECK: sw.epilog:
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; CHECK-NOT: phi
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; CHECK: for.body:
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; CHECK-NOT: switch
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