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cmd/compile: rename a local variable in shortcircuitBlock 

v is pretty generic. Subsequent changes will make this function
more complicated, so rename it now, independently, for easier review.

v is the control value for the block (or its underlying phi);
call it ctl.

Passes toolstash-check.

Updates #37608

Change-Id: I3fbae3344f1c95aff0a69c1e4f61ef637a54774e
Reviewed-on: https://go-review.googlesource.com/c/go/+/222917
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Josh Bleecher Snyder 2020-03-07 13:53:15 -08:00
parent be72e3c3ff
commit 74bc90a9a8
1 changed files with 12 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
src/cmd/compile/internal/ssa/shortcircuit.go
View File

@ -103,24 +103,24 @@ func shortcircuitBlock(b *Block) bool {
// Look for control values of the form Copy(Not(Copy(Phi(const, ...)))).
// Those must be the only values in the b, and they each must be used only by b.
// Track the negations so that we can swap successors as needed later.
v := b.Controls[0]
ctl := b.Controls[0]
nval := 1 // the control value
swap := false
for v.Uses == 1 && v.Block == b && (v.Op == OpCopy || v.Op == OpNot) {
if v.Op == OpNot {
for ctl.Uses == 1 && ctl.Block == b && (ctl.Op == OpCopy || ctl.Op == OpNot) {
if ctl.Op == OpNot {
swap = !swap
}
v = v.Args[0]
ctl = ctl.Args[0]
nval++ // wrapper around control value
}
if len(b.Values) != nval || v.Op != OpPhi || v.Block != b || v.Uses != 1 {
if len(b.Values) != nval || ctl.Op != OpPhi || ctl.Block != b || ctl.Uses != 1 {
return false
}
// Check for const phi args.
var changed bool
for i := 0; i < len(v.Args); i++ {
a := v.Args[i]
for i := 0; i < len(ctl.Args); i++ {
a := ctl.Args[i]
if a.Op != OpConstBool {
continue
}
@ -149,10 +149,10 @@ func shortcircuitBlock(b *Block) bool {
// Remove b's incoming edge from p.
b.removePred(i)
n := len(b.Preds)
v.Args[i].Uses--
v.Args[i] = v.Args[n]
v.Args[n] = nil
v.Args = v.Args[:n]
ctl.Args[i].Uses--
ctl.Args[i] = ctl.Args[n]
ctl.Args[n] = nil
ctl.Args = ctl.Args[:n]
// Redirect p's outgoing edge to t.
p.Succs[pi] = Edge{t, len(t.Preds)}
@ -178,6 +178,6 @@ func shortcircuitBlock(b *Block) bool {
return true
}
phielimValue(v)
phielimValue(ctl)
return true
}