9deee6bffa
D141386 changed the semantics of !range metadata to return poison
on violation. If !range is combined with !noundef, violation is
immediate UB instead, matching the old semantics.
In theory, these IR semantics should also carry over into SDAG.
In practice, DAGCombine has at least one key transform that is
invalid in the presence of poison, namely the conversion of logical
and/or to bitwise and/or (c7b537bf09/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (L11252)).
Ideally, we would fix this transform, but this will require
substantial work to avoid codegen regressions.
In the meantime, avoid transferring !range metadata without
!noundef, effectively restoring the old !range metadata semantics
on the SDAG layer.
Fixes https://github.com/llvm/llvm-project/issues/64589.
Differential Revision: https://reviews.llvm.org/D157685
45 lines
1.0 KiB
LLVM
45 lines
1.0 KiB
LLVM
; RUN: llc < %s -mtriple=aarch64-none-linux-gnu | FileCheck %s
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; and can be eliminated
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; CHECK-LABEL: {{^}}test_call_known_max_range:
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; CHECK: bl foo
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; CHECK-NOT: and
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; CHECK: ret
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define i32 @test_call_known_max_range() #0 {
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entry:
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%id = tail call i32 @foo(), !range !0, !noundef !{}
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%and = and i32 %id, 1023
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ret i32 %and
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}
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; CHECK-LABEL: {{^}}test_call_known_trunc_1_bit_range:
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; CHECK: bl foo
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; CHECK: and w{{[0-9]+}}, w0, #0x1ff
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; CHECK: ret
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define i32 @test_call_known_trunc_1_bit_range() #0 {
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entry:
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%id = tail call i32 @foo(), !range !0, !noundef !{}
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%and = and i32 %id, 511
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ret i32 %and
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}
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; CHECK-LABEL: {{^}}test_call_known_max_range_m1:
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; CHECK: bl foo
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; CHECK: and w{{[0-9]+}}, w0, #0xff
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; CHECK: ret
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define i32 @test_call_known_max_range_m1() #0 {
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entry:
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%id = tail call i32 @foo(), !range !1, !noundef !{}
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%and = and i32 %id, 255
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ret i32 %and
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}
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declare i32 @foo()
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attributes #0 = { norecurse nounwind }
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attributes #1 = { nounwind readnone }
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!0 = !{i32 0, i32 1024}
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!1 = !{i32 0, i32 1023}
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