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[dev.unified] cmd/compile: make Unified IR always writes concrete type for const exprs

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So we don't have to depend on typecheck pass to fixup the concrete
type for some constant expressions. Previously, the problem won't show up,
until CL 418475 sent, which removes an un-necessary type conversion in
"append(a, b...) to help the optimization kicks in.

For #53888

Change-Id: Idaecd38b7abbaa3ad5b00ff3b1fb0fd8bbeb6726
Reviewed-on: https://go-review.googlesource.com/c/go/+/418514
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Cuong Manh Le 2022-07-20 20:27:58 +07:00
parent ae43bdc3e3
commit 131f981df0
3 changed files with 37 additions and 27 deletions
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29
src/cmd/compile/internal/noder/expr.go
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@ -6,7 +6,6 @@ package noder
import (
"fmt"
"go/constant"
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
@ -53,31 +52,9 @@ func (g *irgen) expr(expr syntax.Expr) ir.Node {
base.Assert(g.exprStmtOK)
// The gc backend expects all expressions to have a concrete type, and
// types2 mostly satisfies this expectation already. But there are a few
// cases where the Go spec doesn't require converting to concrete type,
// and so types2 leaves them untyped. So we need to fix those up here.
typ := tv.Type
if basic, ok := typ.(*types2.Basic); ok && basic.Info()&types2.IsUntyped != 0 {
switch basic.Kind() {
case types2.UntypedNil:
// ok; can appear in type switch case clauses
// TODO(mdempsky): Handle as part of type switches instead?
case types2.UntypedInt, types2.UntypedFloat, types2.UntypedComplex:
// Untyped rhs of non-constant shift, e.g. x << 1.0.
// If we have a constant value, it must be an int >= 0.
if tv.Value != nil {
s := constant.ToInt(tv.Value)
assert(s.Kind() == constant.Int && constant.Sign(s) >= 0)
}
typ = types2.Typ[types2.Uint]
case types2.UntypedBool:
typ = types2.Typ[types2.Bool] // expression in "if" or "for" condition
case types2.UntypedString:
typ = types2.Typ[types2.String] // argument to "append" or "copy" calls
default:
base.FatalfAt(g.pos(expr), "unexpected untyped type: %v", basic)
}
typ := idealType(tv)
if typ == nil {
base.FatalfAt(g.pos(expr), "unexpected untyped type: %v", tv.Type)
}
// Constant expression.