0f46e31cfb
As part of the migration to ptradd (https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699), we need to change the representation of the `inrange` attribute, which is used for vtable splitting. Currently, inrange is specified as follows: ``` getelementptr inbounds ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, inrange i32 1, i64 2) ``` The `inrange` is placed on a GEP index, and all accesses must be "in range" of that index. The new representation is as follows: ``` getelementptr inbounds inrange(-16, 16) ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, i32 1, i64 2) ``` This specifies which offsets are "in range" of the GEP result. The new representation will continue working when canonicalizing to ptradd representation: ``` getelementptr inbounds inrange(-16, 16) (i8, ptr @vt, i64 48) ``` The inrange offsets are relative to the return value of the GEP. An alternative design could make them relative to the source pointer instead. The result-relative format was chosen on the off-chance that we want to extend support to non-constant GEPs in the future, in which case this variant is more expressive. This implementation "upgrades" the old inrange representation in bitcode by simply dropping it. This is a very niche feature, and I don't think trying to upgrade it is worthwhile. Let me know if you disagree.
30 lines
591 B
LLVM
30 lines
591 B
LLVM
; RUN: opt -S -passes=globalsplit %s | FileCheck %s
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target datalayout = "e-p:64:64"
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target triple = "x86_64-unknown-linux-gnu"
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; CHECK: @global =
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@global = constant { [2 x ptr], [1 x ptr] } {
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[2 x ptr] [ptr @f, ptr @g],
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[1 x ptr] [ptr @h]
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}
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define ptr @f() {
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ret ptr getelementptr inrange(0, 16) ({ [2 x ptr], [1 x ptr] }, ptr @global, i32 0, i32 0, i32 0)
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}
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define ptr @g() {
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ret ptr null
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}
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define ptr @h() {
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ret ptr null
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}
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define void @foo() {
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%p = call i1 @llvm.type.test(ptr null, metadata !"")
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ret void
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}
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declare i1 @llvm.type.test(ptr, metadata) nounwind readnone
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