cmd/gc: fix walkcompare bugs.
Revision c0e0467635ec (cmd/gc: return canonical Node* from temp)
exposed original nodes of temporaries, allowing callers to mutate
their types.
In walkcompare a temporary could be typed as ideal because of
this. Additionnally, assignment of a comparison result to
a custom boolean type was broken.
Fixes #7366.
LGTM=rsc
R=rsc, iant, khr
CC=golang-codereviews
https://golang.org/cl/66930044
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 97473de..068e38c 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -3171,13 +3171,10 @@
}
if(expr == N)
expr = nodbool(n->op == OEQ);
- typecheck(&expr, Erv);
- walkexpr(&expr, init);
- expr->type = n->type;
- *np = expr;
- return;
+ r = expr;
+ goto ret;
}
-
+
if(t->etype == TSTRUCT && countfield(t) <= 4) {
// Struct of four or fewer fields.
// Inline comparisons.
@@ -3194,13 +3191,10 @@
}
if(expr == N)
expr = nodbool(n->op == OEQ);
- typecheck(&expr, Erv);
- walkexpr(&expr, init);
- expr->type = n->type;
- *np = expr;
- return;
+ r = expr;
+ goto ret;
}
-
+
// Chose not to inline, but still have addresses.
// Call equality function directly.
// The equality function requires a bool pointer for
@@ -3233,10 +3227,7 @@
if(n->op != OEQ)
r = nod(ONOT, r, N);
- typecheck(&r, Erv);
- walkexpr(&r, init);
- *np = r;
- return;
+ goto ret;
hard:
// Cannot take address of one or both of the operands.
@@ -3252,7 +3243,16 @@
r = mkcall1(fn, n->type, init, typename(n->left->type), l, r);
if(n->op == ONE) {
r = nod(ONOT, r, N);
- typecheck(&r, Erv);
+ }
+ goto ret;
+
+ret:
+ typecheck(&r, Erv);
+ walkexpr(&r, init);
+ if(r->type != n->type) {
+ r = nod(OCONVNOP, r, N);
+ r->type = n->type;
+ r->typecheck = 1;
}
*np = r;
return;
diff --git a/test/cmp.go b/test/cmp.go
index 73de502..9ac0ebe 100644
--- a/test/cmp.go
+++ b/test/cmp.go
@@ -387,6 +387,23 @@
isfalse(iz != x)
}
+ // named booleans
+ {
+ type mybool bool
+ var b mybool
+
+ type T struct{ data [20]byte }
+ var x, y T
+ b = x == y
+ istrue(x == y)
+ istrue(bool(b))
+
+ m := make(map[string][10]interface{})
+ b = m["x"] == m["y"]
+ istrue(m["x"] == m["y"])
+ istrue(bool(b))
+ }
+
shouldPanic(p1)
shouldPanic(p2)
shouldPanic(p3)
diff --git a/test/fixedbugs/issue7366.go b/test/fixedbugs/issue7366.go
new file mode 100644
index 0000000..754da6f
--- /dev/null
+++ b/test/fixedbugs/issue7366.go
@@ -0,0 +1,21 @@
+// compile
+
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// issue 7366: generates a temporary with ideal type
+// during comparison of small structs.
+
+package main
+
+type T struct {
+ data [10]byte
+}
+
+func main() {
+ var a T
+ var b T
+ if a == b {
+ }
+}
