Reviewers: jarin,
Description:
[turbofan] Smartify typing of NumberToInt32 and NumberToUint32.
According to ES5 9.5 and 9.6, NaN, -inf, +inf, -0 and 0 all truncate to
zero for both ToInt32 and ToUint32, so we can be a lot smarter in the
typer, loosing less information upon truncation (i.e. x | 0 and x >>> 0).
[email protected]
Please review this at https://codereview.chromium.org/739743003/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+26, -11 lines):
M src/compiler/typer.h
M src/compiler/typer.cc
Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index
996eecd361caacde8ae062304ac1180d68902e75..dd9a02cd92e8decc728c6c15df7d877ae161141f
100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -39,6 +39,18 @@ Typer::Typer(Graph* graph, MaybeHandle<Context> context)
Handle<Object> infinity = f->NewNumber(+V8_INFINITY);
Handle<Object> minusinfinity = f->NewNumber(-V8_INFINITY);
+ Type* number = Type::Number();
+ Type* signed32 = Type::Signed32();
+ Type* unsigned32 = Type::Unsigned32();
+ Type* integral32 = Type::Integral32();
+ Type* object = Type::Object();
+ Type* undefined = Type::Undefined();
+ Type* nan_or_minuszero = Type::Union(Type::NaN(), Type::MinusZero(),
zone);
+ Type* truncating_to_zero =
+ Type::Union(Type::Union(Type::Constant(infinity, zone),
+ Type::Constant(minusinfinity, zone), zone),
+ nan_or_minuszero, zone);
+
negative_signed32 = Type::Union(
Type::SignedSmall(), Type::OtherSigned32(), zone);
non_negative_signed32 = Type::Union(
@@ -49,20 +61,13 @@ Typer::Typer(Graph* graph, MaybeHandle<Context> context)
singleton_zero = Type::Range(zero, zero, zone);
singleton_one = Type::Range(one, one, zone);
zero_or_one = Type::Union(singleton_zero, singleton_one, zone);
- zeroish = Type::Union(
- singleton_zero, Type::Union(Type::NaN(), Type::MinusZero(), zone),
zone);
+ zeroish = Type::Union(singleton_zero, nan_or_minuszero, zone);
+ signed32ish = Type::Union(signed32, truncating_to_zero, zone);
+ unsigned32ish = Type::Union(unsigned32, truncating_to_zero, zone);
falsish = Type::Union(Type::Undetectable(),
Type::Union(zeroish, undefined_or_null, zone), zone);
integer = Type::Range(minusinfinity, infinity, zone);
- weakint = Type::Union(
- integer, Type::Union(Type::NaN(), Type::MinusZero(), zone), zone);
-
- Type* number = Type::Number();
- Type* signed32 = Type::Signed32();
- Type* unsigned32 = Type::Unsigned32();
- Type* integral32 = Type::Integral32();
- Type* object = Type::Object();
- Type* undefined = Type::Undefined();
+ weakint = Type::Union(integer, nan_or_minuszero, zone);
number_fun0_ = Type::Function(number, zone);
number_fun1_ = Type::Function(number, number, zone);
@@ -467,6 +472,10 @@ Type* Typer::Visitor::NumberToInt32(Type* type, Typer*
t) {
// TODO(neis): DCHECK(type->Is(Type::Number()));
if (type->Is(Type::Signed32())) return type;
if (type->Is(t->zeroish)) return t->singleton_zero;
+ if (type->Is(t->signed32ish)) {
+ return Type::Intersect(Type::Union(type, t->singleton_zero, t->zone()),
+ Type::Signed32(), t->zone());
+ }
return Type::Signed32();
}
@@ -475,6 +484,10 @@ Type* Typer::Visitor::NumberToUint32(Type* type,
Typer* t) {
// TODO(neis): DCHECK(type->Is(Type::Number()));
if (type->Is(Type::Unsigned32())) return type;
if (type->Is(t->zeroish)) return t->singleton_zero;
+ if (type->Is(t->unsigned32ish)) {
+ return Type::Intersect(Type::Union(type, t->singleton_zero, t->zone()),
+ Type::Unsigned32(), t->zone());
+ }
return Type::Unsigned32();
}
Index: src/compiler/typer.h
diff --git a/src/compiler/typer.h b/src/compiler/typer.h
index
8491d914af058c87e1f8cfce1aa3959befdf50f0..bfa4bd85d926b15664c2d09f3017838d986005c1
100644
--- a/src/compiler/typer.h
+++ b/src/compiler/typer.h
@@ -47,6 +47,8 @@ class Typer {
Type* singleton_one;
Type* zero_or_one;
Type* zeroish;
+ Type* signed32ish;
+ Type* unsigned32ish;
Type* falsish;
Type* integer;
Type* weakint;
--
--
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