cmd/compile: allow huge rsh in constants arithmetic
Currently an expression like
var v = 0 >> 1000
is rejected by gc with a "stupid shift" error, while gotype
compiles it successfully.
As suggested by gri on the issue tracker, allow an rsh right
operand to be any valid uint value.
Fixes #11328
Change-Id: I6ccb3b7f842338d91fd26ae37dd4fa279d7fc440
Reviewed-on: https://go-review.googlesource.com/13777
Reviewed-by: Robert Griesemer <gri@golang.org>
diff --git a/src/cmd/compile/internal/gc/mparith2.go b/src/cmd/compile/internal/gc/mparith2.go
index 2c7e517..f70e342 100644
--- a/src/cmd/compile/internal/gc/mparith2.go
+++ b/src/cmd/compile/internal/gc/mparith2.go
@@ -229,7 +229,7 @@
}
s := Mpgetfix(b)
- if s < 0 || s >= Mpprec {
+ if s < 0 {
Yyerror("stupid shift: %d", s)
if a.Val.Sign() < 0 {
Mpmovecfix(a, -1)
diff --git a/test/const.go b/test/const.go
index d583659..6c29336 100644
--- a/test/const.go
+++ b/test/const.go
@@ -19,6 +19,9 @@
c3div2 = 3 / 2
c1e3 = 1e3
+ rsh1 = 1e100 >> 1000
+ rsh2 = 1e302 >> 1000
+
ctrue = true
cfalse = !ctrue
)
@@ -48,6 +51,8 @@
assert(c3div2 == 1, "3/2")
assert(c1e3 == 1000, "c1e3 int")
assert(c1e3 == 1e3, "c1e3 float")
+ assert(rsh1 == 0, "rsh1")
+ assert(rsh2 == 9, "rsh2")
// verify that all (in range) are assignable as ints
var i int
