8005033: clear high word for integer pop count on SPARC

Reviewed-by: kvn, twisti
Contributed-by: NRichard Reingruber <richard.reingruber@sap.com>

src/cpu/sparc/vm/sparc.ad

@@ -10224,7 +10224,7 @@ instruct array_equals(o0RegP ary1, o1RegP ary2, g3RegI tmp1, notemp_iRegI result
 
 //---------- Zeros Count Instructions ------------------------------------------
 
-instruct countLeadingZerosI(iRegI dst, iRegI src, iRegI tmp, flagsReg cr) %{
+instruct countLeadingZerosI(iRegIsafe dst, iRegI src, iRegI tmp, flagsReg cr) %{
   predicate(UsePopCountInstruction);  // See Matcher::match_rule_supported
   match(Set dst (CountLeadingZerosI src));
   effect(TEMP dst, TEMP tmp, KILL cr);
@@ -10321,7 +10321,7 @@ instruct countLeadingZerosL(iRegIsafe dst, iRegL src, iRegL tmp, flagsReg cr) %{
   ins_pipe(ialu_reg);
 %}
 
-instruct countTrailingZerosI(iRegI dst, iRegI src, flagsReg cr) %{
+instruct countTrailingZerosI(iRegIsafe dst, iRegI src, flagsReg cr) %{
   predicate(UsePopCountInstruction);  // See Matcher::match_rule_supported
   match(Set dst (CountTrailingZerosI src));
   effect(TEMP dst, KILL cr);
@@ -10364,19 +10364,21 @@ instruct countTrailingZerosL(iRegIsafe dst, iRegL src, flagsReg cr) %{
 
 //---------- Population Count Instructions -------------------------------------
 
-instruct popCountI(iRegI dst, iRegI src) %{
+instruct popCountI(iRegIsafe dst, iRegI src) %{
   predicate(UsePopCountInstruction);
   match(Set dst (PopCountI src));
 
-  format %{ "POPC   $src, $dst" %}
+  format %{ "SRL    $src, G0, $dst\t! clear upper word for 64 bit POPC\n\t"
+            "POPC   $dst, $dst" %}
   ins_encode %{
-    __ popc($src$$Register, $dst$$Register);
+    __ srl($src$$Register, G0, $dst$$Register);
+    __ popc($dst$$Register, $dst$$Register);
   %}
   ins_pipe(ialu_reg);
 %}
 
 // Note: Long.bitCount(long) returns an int.
-instruct popCountL(iRegI dst, iRegL src) %{
+instruct popCountL(iRegIsafe dst, iRegL src) %{
   predicate(UsePopCountInstruction);
   match(Set dst (PopCountL src));
 

test/compiler/8005033/Test8005033.java

+/*
+ * Copyright 2012 SAP AG.  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 8005033
+ * @summary On sparcv9, C2's intrinsic for Integer.bitCount(OV) returns wrong result if OV is the result of an operation with int overflow.
+ * @run main/othervm -Xcomp -XX:CompileOnly=Test8005033::testBitCount Test8005033
+ * @author Richard Reingruber richard DOT reingruber AT sap DOT com
+ */
+
+public class Test8005033 {
+    public static int MINUS_ONE = -1;
+
+    public static void main(String[] args) {
+        System.out.println("EXECUTING test.");
+        Integer.bitCount(1);   // load class
+        int expectedBitCount = 0;
+        int calculatedBitCount = testBitCount();
+        if (expectedBitCount != calculatedBitCount) {
+            throw new InternalError("got " + calculatedBitCount + " but expected " + expectedBitCount);
+        }
+        System.out.println("SUCCESSFULLY passed test.");
+    }
+
+    // testBitCount will be compiled using the Integer.bitCount() intrinsic if possible
+    private static int testBitCount() {
+        return Integer.bitCount(MINUS_ONE+1);   // -1 + 1 => int overflow
+    }
+}