[libcxx-commits] [PATCH] D125019: [libc++] Avoid creating temporaries in unary expressions involving valarray

[Louis Dionne via Phabricator via libcxx-commits]

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Currently, unary expressions involving valarray will create a temporary.
This leads to dangling references in expressions like `-a * b`, because
`-a` is a temporary and the resulting expression will refer to it. This
patch fixes the problem by creating a lazy expression to perform the unary
operation instead of eagerly creating a temporary valarray. This is
permitted by the Standard.

rdar://90152242


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D125019

Files:
  libcxx/include/valarray
  libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/bit_not.pass.cpp
  libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/negate.pass.cpp
  libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/not.pass.cpp
  libcxx/test/std/numerics/numarray/template.valarray/valarray.unary/plus.pass.cpp

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