Add branch hint to unlikely branch of rem_pio2_large

LiamSwayne · andrewrk · commit b976e89c16b4 · 2024-12-23T14:41:43.000-05:00
Adds a `@branchHint` to a 1 in 12 branch of the pi/2 remainder calculation.
diff --git a/lib/compiler_rt/rem_pio2_large.zig b/lib/compiler_rt/rem_pio2_large.zig
@@ -356,6 +356,7 @@ pub fn rem_pio2_large(x: []f64, y: []f64, e0: i32, nx: i32, prec: usize) i32 {
                 }
             }
             if (q0 > 0) { // rare case: chance is 1 in 12
+                @branchHint(.unlikely);
                 switch (q0) {
                     1 => iq[@intCast(jz - 1)] &= 0x7fffff,
                     2 => iq[@intCast(jz - 1)] &= 0x3fffff,

Original file line number	Diff line number	Diff line change
`@@ -356,6 +356,7 @@ pub fn rem_pio2_large(x: []f64, y: []f64, e0: i32, nx: i32, prec: usize) i32 {`
`356`	`356`	`}`
`357`	`357`	`}`
`358`	`358`	`if (q0 > 0) { // rare case: chance is 1 in 12`
	`359`	`+ @branchHint(.unlikely);`
`359`	`360`	`switch (q0) {`
`360`	`361`	`1 => iq[@intCast(jz - 1)] &= 0x7fffff,`
`361`	`362`	`2 => iq[@intCast(jz - 1)] &= 0x3fffff,`