[llvm] [DebugInfo] Pack DILocation hash inputs (PR #196556)

[Nikita Popov via llvm-commits]

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@@ -347,9 +349,9 @@ template <> struct MDNodeKeyImpl<DILocation> {
     // outweighed by the overall compile time savings by performing this check.
     // * (hash_combine(x) != hash_combine(x, 0))
     if (AtomGroup || AtomRank)
-      return hash_combine(Line, Column, Scope, InlinedAt, ImplicitCode,
-                          AtomGroup, (uint8_t)AtomRank);
-    return hash_combine(Line, Column, Scope, InlinedAt, ImplicitCode);
+      return hash_combine(LineColumnAndImplicitCode, Scope, InlinedAt,
+                          (AtomGroup << 3) | AtomRank);
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nikic wrote:

Inverting this is slightly more efficient because it matches the memory layout: https://clang.godbolt.org/z/qcfqv13T7

https://github.com/llvm/llvm-project/pull/196556