cmd/compile/internal/gc: treat cap/len as safe in mayAffectMemory
OLEN and OCAP can't affect memory state as long as their
arguments don't.
Re-organized case bodies to avoid duplicating same branches for
recursive invocations.
Change-Id: I30407143429f7dd1891badb70df88969ed267535
Reviewed-on: https://go-review.googlesource.com/133555
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
index 9db6c8e..254427b 100644
--- a/src/cmd/compile/internal/gc/esc.go
+++ b/src/cmd/compile/internal/gc/esc.go
@@ -689,18 +689,16 @@
switch n.Op {
case ONAME, OCLOSUREVAR, OLITERAL:
return false
- case ODOT, ODOTPTR:
- return e.mayAffectMemory(n.Left)
- case OIND, OCONVNOP:
- return e.mayAffectMemory(n.Left)
- case OCONV:
- return e.mayAffectMemory(n.Left)
- case OINDEX:
+
+ // Left+Right group.
+ case OINDEX, OADD, OSUB, OOR, OXOR, OMUL, OLSH, ORSH, OAND, OANDNOT, ODIV, OMOD:
return e.mayAffectMemory(n.Left) || e.mayAffectMemory(n.Right)
- case OADD, OSUB, OOR, OXOR, OMUL, OLSH, ORSH, OAND, OANDNOT, ODIV, OMOD:
- return e.mayAffectMemory(n.Left) || e.mayAffectMemory(n.Right)
- case ONOT, OCOM, OPLUS, OMINUS, OALIGNOF, OOFFSETOF, OSIZEOF:
+
+ // Left group.
+ case ODOT, ODOTPTR, OIND, OCONVNOP, OCONV, OLEN, OCAP,
+ ONOT, OCOM, OPLUS, OMINUS, OALIGNOF, OOFFSETOF, OSIZEOF:
return e.mayAffectMemory(n.Left)
+
default:
return true
}