The only source change is a speedup to pow5Factor.
Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
libstdc++-v3/ChangeLog:
* src/c++17/ryu/MERGE: Update the commit hash.
* src/c++17/ryu/d2s_intrinsics.h: Merge from Ryu's master
branch.
---
libstdc++-v3/src/c++17/ryu/MERGE | 2 +-
libstdc++-v3/src/c++17/ryu/d2s_intrinsics.h | 9 ++++-----
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/libstdc++-v3/src/c++17/ryu/MERGE b/libstdc++-v3/src/c++17/ryu/MERGE
index 0ea65add2ff..9035502846e 100644
--- a/libstdc++-v3/src/c++17/ryu/MERGE
+++ b/libstdc++-v3/src/c++17/ryu/MERGE
@@ -1,4 +1,4 @@
-22c887c017a8512abcd4a8f6bfcdb2742829cd7d
+150d0c87830756d34e76c42f7f33f811d89903a8
The first line of this file holds the git revision number of the
last merge done from the master library sources.
diff --git a/libstdc++-v3/src/c++17/ryu/d2s_intrinsics.h
b/libstdc++-v3/src/c++17/ryu/d2s_intrinsics.h
index bbac4dfd48f..e3206b5d7dd 100644
--- a/libstdc++-v3/src/c++17/ryu/d2s_intrinsics.h
+++ b/libstdc++-v3/src/c++17/ryu/d2s_intrinsics.h
@@ -181,15 +181,14 @@ static inline uint32_t mod1e9(const uint64_t x) {
#endif // defined(RYU_32_BIT_PLATFORM)
static inline uint32_t pow5Factor(uint64_t value) {
+ const uint64_t m_inv_5 = 14757395258967641293u; // 5 * m_inv_5 = 1 (mod 2^64)
+ const uint64_t n_div_5 = 3689348814741910323u; // #{ n | n = 0 (mod 2^64) }
= 2^64 / 5
uint32_t count = 0;
for (;;) {
assert(value != 0);
- const uint64_t q = div5(value);
- const uint32_t r = ((uint32_t) value) - 5 * ((uint32_t) q);
- if (r != 0) {
+ value *= m_inv_5;
+ if (value > n_div_5)
break;
- }
- value = q;
++count;
}
return count;
--
2.34.0
