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| author | Duncan P. N. Exon Smith <dexonsmith@apple.com> | 2016-04-23 04:42:39 +0000 |
|---|---|---|
| committer | Duncan P. N. Exon Smith <dexonsmith@apple.com> | 2016-04-23 04:42:39 +0000 |
| commit | e7a2c97bc25b03f13046949bd767a8207f774cf7 (patch) | |
| tree | 5f55a7530e20a5ba5006c5d339c63f56e815a791 /test/Bitcode | |
| parent | bcf5d1ff2006ac61d30fa7da5a98840df9b3c8d7 (diff) | |
BitcodeWriter: Emit distinct nodes before uniqued nodes
When an operand of a distinct node hasn't been read yet, the reader can
use a DistinctMDOperandPlaceholder. This is much cheaper than forward
referencing from a uniqued node. Change
ValueEnumerator::organizeMetadata to partition distinct nodes and
uniqued nodes to reduce the overhead of cycles broken by distinct nodes.
Mehdi measured this for me; this removes most of the RAUW from the
importing step of -flto=thin, even after a WIP patch that removes
string-based DITypeRefs (introducing many more cycles to the metadata
graph).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267276 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Bitcode')
| -rw-r--r-- | test/Bitcode/mdnodes-distinct-nodes-first.ll | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/test/Bitcode/mdnodes-distinct-nodes-first.ll b/test/Bitcode/mdnodes-distinct-nodes-first.ll new file mode 100644 index 000000000000..1d146817e6b0 --- /dev/null +++ b/test/Bitcode/mdnodes-distinct-nodes-first.ll @@ -0,0 +1,18 @@ +; RUN: llvm-as <%s | llvm-bcanalyzer -dump | FileCheck %s +; Check that distinct nodes are emitted before uniqued nodes, even if that +; breaks post-order traversals. + +; Nodes in this testcase are numbered to match how they are referenced in +; bitcode. !1 is referenced as opN=1. + +; CHECK: <DISTINCT_NODE op0=2/> +!1 = distinct !{!2} + +; CHECK-NEXT: <NODE op0=1/> +!2 = !{!1} + +; Note: named metadata nodes are not cannot reference null so their operands +; are numbered off-by-one. +; CHECK-NEXT: <NAME +; CHECK-NEXT: <NAMED_NODE op0=1/> +!named = !{!2} |