[llvm] r357761 - [llvm] Add isa_and_nonnull
Don Hinton via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 5 06:59:24 PDT 2019
Author: dhinton
Date: Fri Apr 5 06:59:24 2019
New Revision: 357761
URL: http://llvm.org/viewvc/llvm-project?rev=357761&view=rev
Log:
[llvm] Add isa_and_nonnull
Summary:
Add new ``isa_and_nonnull<>`` operator that works just like
the ``isa<>`` operator, except that it allows for a null pointer as an
argument (which it then returns false).
Reviewers: lattner, aaron.ballman, greened
Reviewed By: lattner
Subscribers: hubert.reinterpretcast, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60291
Modified:
llvm/trunk/docs/ProgrammersManual.rst
llvm/trunk/include/llvm/Support/Casting.h
llvm/trunk/unittests/Support/Casting.cpp
Modified: llvm/trunk/docs/ProgrammersManual.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/ProgrammersManual.rst?rev=357761&r1=357760&r2=357761&view=diff
==============================================================================
--- llvm/trunk/docs/ProgrammersManual.rst (original)
+++ llvm/trunk/docs/ProgrammersManual.rst Fri Apr 5 06:59:24 2019
@@ -164,6 +164,12 @@ rarely have to include this file directl
efficient to use the ``InstVisitor`` class to dispatch over the instruction
type directly.
+``isa_and_nonnull<>``:
+ The ``isa_and_nonnull<>`` operator works just like the ``isa<>`` operator,
+ except that it allows for a null pointer as an argument (which it then
+ returns false). This can sometimes be useful, allowing you to combine several
+ null checks into one.
+
``cast_or_null<>``:
The ``cast_or_null<>`` operator works just like the ``cast<>`` operator,
except that it allows for a null pointer as an argument (which it then
Modified: llvm/trunk/include/llvm/Support/Casting.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Casting.h?rev=357761&r1=357760&r2=357761&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Casting.h (original)
+++ llvm/trunk/include/llvm/Support/Casting.h Fri Apr 5 06:59:24 2019
@@ -143,6 +143,16 @@ template <class X, class Y> LLVM_NODISCA
typename simplify_type<const Y>::SimpleType>::doit(Val);
}
+// isa_and_nonnull<X> - Functionally identical to isa, except that a null value
+// is accepted.
+//
+template <class X, class Y>
+LLVM_NODISCARD inline bool isa_and_nonnull(const Y &Val) {
+ if (!Val)
+ return false;
+ return isa<X>(Val);
+}
+
//===----------------------------------------------------------------------===//
// cast<x> Support Templates
//===----------------------------------------------------------------------===//
Modified: llvm/trunk/unittests/Support/Casting.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/Casting.cpp?rev=357761&r1=357760&r2=357761&view=diff
==============================================================================
--- llvm/trunk/unittests/Support/Casting.cpp (original)
+++ llvm/trunk/unittests/Support/Casting.cpp Fri Apr 5 06:59:24 2019
@@ -118,6 +118,12 @@ TEST(CastingTest, isa) {
EXPECT_TRUE(isa<foo>(B4));
}
+TEST(CastingTest, isa_and_nonnull) {
+ EXPECT_TRUE(isa_and_nonnull<foo>(B2));
+ EXPECT_TRUE(isa_and_nonnull<foo>(B4));
+ EXPECT_FALSE(isa_and_nonnull<foo>(fub()));
+}
+
TEST(CastingTest, cast) {
foo &F1 = cast<foo>(B1);
EXPECT_NE(&F1, null_foo);
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