[libcxx-commits] [PATCH] D129931: [libc++][format] Use to_chars internals.

[Mark de Wever via Phabricator via libcxx-commits]

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The external to_chars interface does some validations already done in
format. So instead of doing the same validations again, directly call
the internals of to_chars.

This has a small size benefit

    text	   data	    bss	    dec	    hex	filename
  718800	  12472	    488	 731760	  b2a70	./formatter_int.libcxx.out-baseline
  714915	  12472	    488	 727875	  b1b43	./formatter_int.libcxx.out

And a small performance benefit for simple formatting:

  Comparing ./formatter_int.libcxx.out-baseline to ./formatter_int.libcxx.out
  Benchmark                                                               Time             CPU      Time Old      Time New       CPU Old       CPU New
  ----------------------------------------------------------------------------------------------------------------------------------------------------
  BM_Basic<uint32_t>                                                   -0.1139         -0.1125            61            54            61            54
  BM_Basic<int32_t>                                                    -0.0265         -0.0250            62            60            62            60
  BM_Basic<uint64_t>                                                   +0.0051         +0.0069            82            83            82            83
  BM_Basic<int64_t>                                                    +0.0084         +0.0101            82            83            82            83
  BM_BasicLow<__uint128_t>                                             -0.0588         -0.0572            87            82            87            82
  BM_BasicLow<__int128_t>                                              -0.0548         -0.0532            88            83            88            83
  BM_Basic<__uint128_t>                                                -0.0253         -0.0238           239           233           238           233
  BM_Basic<__int128_t>                                                 -0.0346         -0.0331           222           214           222           214


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D129931

Files:
  libcxx/include/__format/formatter_integral.h

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