mirror
/
go
mirror of https://github.com/golang/go.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

runtime: eliminate a conditional branch from heapBits.bits 

Change-Id: I1fa5e629b2890a8509559ce4ea17b74f47d71925
Reviewed-on: https://go-review.googlesource.com/19637
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Austin Clements 2016-01-21 13:44:16 -05:00
parent 0168c2676f
commit 4eb33f6b8d
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/runtime/mbitmap.go
View File

@ -290,7 +290,9 @@ func (h heapBits) forward(n uintptr) heapBits {
// The result includes in its higher bits the bits for subsequent words
// described by the same bitmap byte.
func (h heapBits) bits() uint32 {
return uint32(*h.bitp) >> h.shift
// The (shift & 31) eliminates a test and conditional branch
// from the generated code.
return uint32(*h.bitp) >> (h.shift & 31)
}
// isMarked reports whether the heap bits have the marked bit set.