8074869: C2 code generator can replace -0.0f with +0.0f on Linux
Summary: Instead of 'fpclass', use cast float->int and double->long to check if value is +0.0f and +0.0d, respectively.
Reviewed-by: kvn, simonis, dlong
--- a/hotspot/src/cpu/aarch64/vm/aarch64.ad Mon Feb 16 14:07:36 2015 +0100
+++ b/hotspot/src/cpu/aarch64/vm/aarch64.ad Sat Mar 14 11:21:04 2015 +0100
@@ -3735,12 +3735,12 @@
interface(CONST_INTER);
%}
-// constant 'double +0.0'.
+// Double Immediate: +0.0d
operand immD0()
%{
- predicate((n->getd() == 0) &&
- (fpclassify(n->getd()) == FP_ZERO) && (signbit(n->getd()) == 0));
+ predicate(jlong_cast(n->getd()) == 0);
match(ConD);
+
op_cost(0);
format %{ %}
interface(CONST_INTER);
@@ -3765,12 +3765,12 @@
interface(CONST_INTER);
%}
-// constant 'float +0.0'.
+// Float Immediate: +0.0f.
operand immF0()
%{
- predicate((n->getf() == 0) &&
- (fpclassify(n->getf()) == FP_ZERO) && (signbit(n->getf()) == 0));
+ predicate(jint_cast(n->getf()) == 0);
match(ConF);
+
op_cost(0);
format %{ %}
interface(CONST_INTER);
--- a/hotspot/src/cpu/ppc/vm/ppc.ad Mon Feb 16 14:07:36 2015 +0100
+++ b/hotspot/src/cpu/ppc/vm/ppc.ad Sat Mar 14 11:21:04 2015 +0100
@@ -4416,11 +4416,11 @@
interface(CONST_INTER);
%}
-// constant 'float +0.0'.
+// Float Immediate: +0.0f.
operand immF_0() %{
- predicate((n->getf() == 0) &&
- (fpclassify(n->getf()) == FP_ZERO) && (signbit(n->getf()) == 0));
+ predicate(jint_cast(n->getf()) == 0);
match(ConF);
+
op_cost(0);
format %{ %}
interface(CONST_INTER);
--- a/hotspot/src/cpu/sparc/vm/sparc.ad Mon Feb 16 14:07:36 2015 +0100
+++ b/hotspot/src/cpu/sparc/vm/sparc.ad Sat Mar 14 11:21:04 2015 +0100
@@ -3758,13 +3758,9 @@
interface(CONST_INTER);
%}
+// Double Immediate: +0.0d
operand immD0() %{
-#ifdef _LP64
- // on 64-bit architectures this comparision is faster
predicate(jlong_cast(n->getd()) == 0);
-#else
- predicate((n->getd() == 0) && (fpclass(n->getd()) == FP_PZERO));
-#endif
match(ConD);
op_cost(0);
@@ -3781,9 +3777,9 @@
interface(CONST_INTER);
%}
-// Float Immediate: 0
+// Float Immediate: +0.0f
operand immF0() %{
- predicate((n->getf() == 0) && (fpclass(n->getf()) == FP_PZERO));
+ predicate(jint_cast(n->getf()) == 0);
match(ConF);
op_cost(0);
--- a/hotspot/src/share/vm/utilities/globalDefinitions_gcc.hpp Mon Feb 16 14:07:36 2015 +0100
+++ b/hotspot/src/share/vm/utilities/globalDefinitions_gcc.hpp Sat Mar 14 11:21:04 2015 +0100
@@ -44,14 +44,6 @@
#endif // SOLARIS
#include <math.h>
-#ifndef FP_PZERO
-// Linux doesn't have positive/negative zero
-#define FP_PZERO FP_ZERO
-#endif
-#if (!defined fpclass) && ((!defined SPARC) || (!defined SOLARIS))
-#define fpclass fpclassify
-#endif
-
#include <time.h>
#include <fcntl.h>
#include <dlfcn.h>
--- a/hotspot/src/share/vm/utilities/globalDefinitions_sparcWorks.hpp Mon Feb 16 14:07:36 2015 +0100
+++ b/hotspot/src/share/vm/utilities/globalDefinitions_sparcWorks.hpp Sat Mar 14 11:21:04 2015 +0100
@@ -48,15 +48,6 @@
# include <ieeefp.h>
#endif
# include <math.h>
-#ifdef LINUX
-#ifndef FP_PZERO
- // Linux doesn't have positive/negative zero
- #define FP_PZERO FP_ZERO
-#endif
-#ifndef fpclass
- #define fpclass fpclassify
-#endif
-#endif
# include <time.h>
# include <fcntl.h>
# include <dlfcn.h>
--- a/hotspot/src/share/vm/utilities/globalDefinitions_xlc.hpp Mon Feb 16 14:07:36 2015 +0100
+++ b/hotspot/src/share/vm/utilities/globalDefinitions_xlc.hpp Sat Mar 14 11:21:04 2015 +0100
@@ -41,14 +41,6 @@
#include <wchar.h>
#include <math.h>
-#ifndef FP_PZERO
-// Linux doesn't have positive/negative zero
-#define FP_PZERO FP_ZERO
-#endif
-#if (!defined fpclass)
-#define fpclass fpclassify
-#endif
-
#include <time.h>
#include <fcntl.h>
#include <dlfcn.h>
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/loopopts/ConstFPVectorization.java Sat Mar 14 11:21:04 2015 +0100
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+/**
+ * @test
+ * @bug 8074869
+ * @summary C2 code generator can replace -0.0f with +0.0f on Linux
+ * @run main ConstFPVectorization 8
+ * @author volker.simonis@gmail.com
+ *
+ */
+
+public class ConstFPVectorization {
+
+ static float[] f = new float[16];
+ static double[] d = new double[16];
+
+ static void floatLoop(int count) {
+ for (int i = 0; i < count; i++) {
+ f[i] = -0.0f;
+ }
+ }
+
+ static void doubleLoop(int count) {
+ for (int i = 0; i < count; i++) {
+ d[i] = -0.0d;
+ }
+ }
+
+ public static void main(String args[]) {
+ for (int i = 0; i < 10_000; i++) {
+ floatLoop(Integer.parseInt(args[0]));
+ doubleLoop(Integer.parseInt(args[0]));
+ }
+ for (int i = 0; i < Integer.parseInt(args[0]); i++) {
+ if (Float.floatToRawIntBits(f[i]) != Float.floatToRawIntBits(-0.0f))
+ throw new Error("Float error at index " + i);
+ if (Double.doubleToRawLongBits(d[i]) != Double.doubleToRawLongBits(-0.0d))
+ throw new Error("Double error at index " + i);
+ }
+ }
+}