From 078b89b3c046d230ef3ad39494e5852184eb528b Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Wed, 23 Oct 2019 19:35:39 -0700 Subject: Export of internal Abseil changes -- e54b9c7bbb0c58475676c268e2e19c69f4bce48a by Jorg Brown : Tweak ABSL_PREDICT_TRUE slightly, for better code on some platforms and/or optimization levels. "false || (x)" is more verbose than "!!(x)", but ultimately more efficient. For example, given this code: void InitIfNecessary() { if (ABSL_PREDICT_TRUE(NeedsInit())) { SlowInitIfNecessary(); } } Clang with default optimization level will produce: Before this CL After this CL InitIfNecessary: InitIfNecessary: push rbp push rbp mov rbp, rsp mov rbp, rsp call NeedsInit call NeedsInit xor al, -1 xor al, -1 test al, 1 test al, 1 jne .LBB2_1 jne .LBB3_1 jmp .LBB2_2 jmp .LBB3_2 .LBB2_1: .LBB3_1: call SlowInitIfNecessary call SlowInitIfNecessary .LBB2_2: .LBB3_2: pop rbp pop rbp ret ret PiperOrigin-RevId: 276401386 -- 0a3c4dfd8342bf2b1b11a87f1c662c883f73cab7 by Abseil Team : Fix comment nit: sem_open => sem_init. The code calls sem_init, not sem_open, to initialize an unnamed semaphore. (sem_open creates or opens a named semaphore.) PiperOrigin-RevId: 276344072 -- b36a664e9459057509a90e83d3482e1d3a4c44c7 by Abseil Team : Fix typo in flat_hash_map.h: exchaged -> exchanged PiperOrigin-RevId: 276295792 -- 7bbd8d18276eb110c8335743e35fceb662ddf3d6 by Samuel Benzaquen : Add assertions to verify use of iterators. PiperOrigin-RevId: 276283300 -- 677398a8ffcb1f59182cffe57a4fe7ff147a0404 by Laramie Leavitt : Migrate distribution_impl.h/cc to generate_real.h/cc. Combine the methods RandU64To into a single method: GenerateRealFromBits(). Remove rejection sampling from absl::uniform_real_distribution. PiperOrigin-RevId: 276158675 -- c60c9d11d24b0c546329d998e78e15a84b3153f5 by Abseil Team : Internal change PiperOrigin-RevId: 276126962 -- 4c840cab6a8d86efa29b397cafaf7520eece68cc by Andy Soffer : Update CMakeLists.txt to address https://github.com/abseil/abseil-cpp/issues/365. This does not cover every platform, but it does at least address the first-order issue of assuming gcc implies x86. PiperOrigin-RevId: 276116253 -- 98da366e6b5d51afe5d7ac6722126aca23d85ee6 by Abseil Team : Internal change PiperOrigin-RevId: 276097452 GitOrigin-RevId: e54b9c7bbb0c58475676c268e2e19c69f4bce48a Change-Id: I02d84454bb71ab21ad3d39650acf6cc6e36f58d7 --- absl/random/uniform_real_distribution.h | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'absl/random/uniform_real_distribution.h') diff --git a/absl/random/uniform_real_distribution.h b/absl/random/uniform_real_distribution.h index 336abb3..bf2ed2c 100644 --- a/absl/random/uniform_real_distribution.h +++ b/absl/random/uniform_real_distribution.h @@ -39,8 +39,9 @@ #include #include -#include "absl/random/internal/distribution_impl.h" +#include "absl/meta/type_traits.h" #include "absl/random/internal/fast_uniform_bits.h" +#include "absl/random/internal/generate_real.h" #include "absl/random/internal/iostream_state_saver.h" namespace absl { @@ -76,6 +77,7 @@ class uniform_real_distribution { // is not possible, so value generation cannot use the full range of the // real type. assert(range_ <= (std::numeric_limits::max)()); + assert(std::isfinite(range_)); } result_type a() const { return lo_; } @@ -151,10 +153,15 @@ template typename uniform_real_distribution::result_type uniform_real_distribution::operator()( URBG& gen, const param_type& p) { // NOLINT(runtime/references) - using random_internal::PositiveValueT; + using random_internal::GeneratePositiveTag; + using random_internal::GenerateRealFromBits; + using real_type = + absl::conditional_t::value, float, double>; + while (true) { - const result_type sample = random_internal::RandU64ToReal< - result_type>::template Value(fast_u64_(gen)); + const result_type sample = + GenerateRealFromBits( + fast_u64_(gen)); const result_type res = p.a() + (sample * p.range_); if (res < p.b() || p.range_ <= 0 || !std::isfinite(p.range_)) { return res; -- cgit v1.2.3