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| author | Guillaume Gomez <guillaume1.gomez@gmail.com> | 2021-03-02 00:50:11 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-03-02 00:50:11 +0100 |
| commit | 9a0ac7cb5feed93eb0b05468c07c2bb8cdea234b (patch) | |
| tree | 7ff49eb9ee43279a44b290f0678ca87502557209 | |
| parent | 0c6b69aa70d63976f119af1949820af13fdd491b (diff) | |
| parent | bd51dea6934d5c583fe9c8bc806e6287cac43f90 (diff) | |
| download | rust-9a0ac7cb5feed93eb0b05468c07c2bb8cdea234b.tar.gz rust-9a0ac7cb5feed93eb0b05468c07c2bb8cdea234b.zip | |
Rollup merge of #82676 - dtolnay:powers, r=Mark-Simulacrum
Change twice used large const table to static This table is used twice in core::num::dec2flt::algorithm::power_of_ten. According to the semantics of const, a separate huge definition of the table is inlined at both places. https://github.com/rust-lang/rust/blob/5233edcf1c7ee70ac25e4ec1115c3546f53d8a2d/library/core/src/num/dec2flt/algorithm.rs#L16-L22 Theoretically this gets cleaned up by optimization passes, but in practice I am experiencing a miscompile from LTO on this code. Making the table a static, which would only be defined a single time and not require attention from LTO, eliminates the miscompile and seems semantically more appropriate anyway. A separate bug report on the LTO bug is forthcoming. Original addition of `const` is from #27307.
| -rw-r--r-- | library/core/src/num/dec2flt/table.rs | 2 | ||||
| -rwxr-xr-x | src/etc/dec2flt_table.py | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/library/core/src/num/dec2flt/table.rs b/library/core/src/num/dec2flt/table.rs index 1bd94ffa04e..97b497e81e0 100644 --- a/library/core/src/num/dec2flt/table.rs +++ b/library/core/src/num/dec2flt/table.rs @@ -5,7 +5,7 @@ pub const MIN_E: i16 = -305; pub const MAX_E: i16 = 305; #[rustfmt::skip] -pub const POWERS: ([u64; 611], [i16; 611]) = ( +pub static POWERS: ([u64; 611], [i16; 611]) = ( [ 0xe0b62e2929aba83c, 0x8c71dcd9ba0b4926, diff --git a/src/etc/dec2flt_table.py b/src/etc/dec2flt_table.py index 9bbcaf7c4cc..ad2292e8571 100755 --- a/src/etc/dec2flt_table.py +++ b/src/etc/dec2flt_table.py @@ -113,7 +113,7 @@ def print_proper_powers(): print() print("#[rustfmt::skip]") typ = "([u64; {0}], [i16; {0}])".format(len(powers)) - print("pub const POWERS: ", typ, " = (", sep='') + print("pub static POWERS: ", typ, " = (", sep='') print(" [") for z in powers: print(" 0x{:x},".format(z.sig)) |