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add branchHint to std.Random.float

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David Rubin 2024-12-12 18:23:48 -08:00 • committed by Alex Rønne Petersen
parent a68119f8f1
commit 82f35c5186
1 changed files with 3 additions and 3 deletions
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6
lib/std/Random.zig
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@ -271,11 +271,10 @@ pub fn float(r: Random, comptime T: type) T {
const rand = r.int(u64); const rand = r.int(u64);
var rand_lz = @clz(rand); var rand_lz = @clz(rand);
if (rand_lz >= 41) { if (rand_lz >= 41) {
// TODO: when #5177 or #489 is implemented, @branchHint(.unlikely);
// tell the compiler it is unlikely (1/2^41) to reach this point.
// (Same for the if branch and the f64 calculations below.)
rand_lz = 41 + @clz(r.int(u64)); rand_lz = 41 + @clz(r.int(u64));
if (rand_lz == 41 + 64) { if (rand_lz == 41 + 64) {
@branchHint(.unlikely);
// It is astronomically unlikely to reach this point. // It is astronomically unlikely to reach this point.
rand_lz += @clz(r.int(u32) | 0x7FF); rand_lz += @clz(r.int(u32) | 0x7FF);
} }
@ -297,6 +296,7 @@ pub fn float(r: Random, comptime T: type) T {
const addl_rand_lz = @clz(r.int(u64)); const addl_rand_lz = @clz(r.int(u64));
rand_lz += addl_rand_lz; rand_lz += addl_rand_lz;
if (addl_rand_lz != 64) { if (addl_rand_lz != 64) {
@branchHint(.likely);
break; break;
} }
if (rand_lz >= 1022) { if (rand_lz >= 1022) {