IR: Add 'distinct' MDNodes to bitcode and assembly

Propagate whether `MDNode`s are 'distinct' through the other types of IR
(assembly and bitcode).  This adds the `distinct` keyword to assembly.

Currently, no one actually calls `MDNode::getDistinct()`, so these nodes
only get created for:

  - self-references, which are never uniqued, and
  - nodes whose operands are replaced that hit a uniquing collision.

The concept of distinct nodes is still not quite first-class, since
distinct-ness doesn't yet survive across `MapMetadata()`.

Part of PR22111.

llvm-svn: 225474

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/vectorize-once.ll b/llvm/test/Transforms/LoopVectorize/vectorize-once.ll
index 30fdd8f3158..a9b2a53f74b 100644
--- a/llvm/test/Transforms/LoopVectorize/vectorize-once.ll
+++ b/llvm/test/Transforms/LoopVectorize/vectorize-once.ll
@@ -68,10 +68,10 @@ _ZSt10accumulateIPiiET0_T_S2_S1_.exit:            ; preds = %for.body.i, %entry
 
 attributes #0 = { nounwind readonly ssp uwtable "fp-contract-model"="standard" "no-frame-pointer-elim" "no-frame-pointer-elim-non-leaf" "realign-stack" "relocation-model"="pic" "ssp-buffers-size"="8" }
 
-; CHECK: !0 = !{!0, !1, !2}
+; CHECK: !0 = distinct !{!0, !1, !2}
 ; CHECK: !1 = !{!"llvm.loop.vectorize.width", i32 1}
 ; CHECK: !2 = !{!"llvm.loop.interleave.count", i32 1}
-; CHECK: !3 = !{!3, !1, !2}
+; CHECK: !3 = distinct !{!3, !1, !2}
 
 !0 = !{!0, !1}
 !1 = !{!"llvm.loop.vectorize.width", i32 1}