Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

cmd/compile: optimize Add64carry with unused carries into plain Add64

Browse source 
Change-Id: I8a63f567cfc574bb066ad6269eec6929760cb9c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/656338
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Jorropo <jorropo.pgm@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
This commit is contained in:
Jorropo 2025-03-10 09:27:39 +01:00 • committed by Gopher Robot
parent 2ce5aab79e
commit 5453b788fd
2 changed files with 23 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

4
src/cmd/compile/internal/ssa/_gen/generic.rules
View file

@ -629,6 +629,10 @@
(Sub(64|32|16|8) (Com(64|32|16|8) x) (Neg(64|32|16|8) x)) => (Const(64|32|16|8) [-1])
(Add(64|32|16|8) (Com(64|32|16|8) x) x) => (Const(64|32|16|8) [-1])
// Prove does not simplify this because x + y might overflow into carry,
// however if no one care about the carry, let it overflow in a normal add.
(Select0 a:(Add64carry x y (Const64 [0]))) && a.Uses == 1 => (Add64 x y)
// Simplification when involving common integer
// (t + x) - (t + y) == x - y
// (t + x) - (y + t) == x - y

19
src/cmd/compile/internal/ssa/rewritegeneric.go
View file

@ -30274,6 +30274,25 @@ func rewriteValuegeneric_OpRsh8x8(v *Value) bool {
}
func rewriteValuegeneric_OpSelect0(v *Value) bool {
v_0 := v.Args[0]
// match: (Select0 a:(Add64carry x y (Const64 [0])))
// cond: a.Uses == 1
// result: (Add64 x y)
for {
a := v_0
if a.Op != OpAdd64carry {
break
}
_ = a.Args[2]
x := a.Args[0]
y := a.Args[1]
a_2 := a.Args[2]
if a_2.Op != OpConst64 || auxIntToInt64(a_2.AuxInt) != 0 || !(a.Uses == 1) {
break
}
v.reset(OpAdd64)
v.AddArg2(x, y)
return true
}
// match: (Select0 (MakeTuple x y))
// result: x
for {