qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-10-05 16:41:21 -06:00
Code Releases Activity

[dev.ssa] cmd/compile: rewrite if not

Browse Source 
Rewrite if !cond by swapping the branches and removing the not.

Change-Id: If3af1bac02bfc566faba872a8c7f7e5ce38e9f58
Reviewed-on: https://go-review.googlesource.com/12610
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This commit is contained in:
Todd Neal 2015-07-23 18:44:09 -05:00
parent 7e74e43366
commit 52d76f7a6a
2 changed files with 21 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/cmd/compile/internal/ssa/gen/generic.rules
View File

@ -51,5 +51,6 @@
(StringLen (StringMake _ len)) -> len
(Store dst str mem) && str.Type.IsString() -> (Store (OffPtr <TypeBytePtr> [config.PtrSize] dst) (StringLen <config.Uintptr> str) (Store <TypeMem> dst (StringPtr <TypeBytePtr> str) mem))
(If (Not cond) yes no) -> (If cond no yes)
(If (Const {c}) yes no) && c.(bool) -> (Plain nil yes)
(If (Const {c}) yes no) && !c.(bool) -> (Plain nil no)

20
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -495,6 +495,26 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
func rewriteBlockgeneric(b *Block) bool {
switch b.Kind {
case BlockIf:
// match: (If (Not cond) yes no)
// cond:
// result: (If cond no yes)
{
v := b.Control
if v.Op != OpNot {
goto endebe19c1c3c3bec068cdb2dd29ef57f96
}
cond := v.Args[0]
yes := b.Succs[0]
no := b.Succs[1]
b.Kind = BlockIf
b.Control = cond
b.Succs[0] = no
b.Succs[1] = yes
return true
}
goto endebe19c1c3c3bec068cdb2dd29ef57f96
endebe19c1c3c3bec068cdb2dd29ef57f96:
;
// match: (If (Const {c}) yes no)
// cond: c.(bool)
// result: (Plain nil yes)