[vmkit-commits] [PATCH] Fix LSHL to mask the shift operand.

[Will Dietz]

Inlined below.

The masking logic is already used in LUSHR, FWIW.

~Will

>From 029662fa7bd23532d8a5be59793efab715217356 Mon Sep 17 00:00:00 2001
From: Will Dietz <w at wdtz.org>
Date: Sun, 6 Nov 2011 23:26:17 -0600
Subject: [PATCH] Fix LSHL to mask the shift operand.

Simple test case illustrating failure:

class Test {
   public static void main(String[] args) {
     long l = 1;
     System.out.println(l);
     System.out.println(l << 10);
     System.out.println(l << 32);
     System.out.println(l << 64);
     System.out.println(l << 128);
     System.out.println(l << -10);
   }
}

Should produce (java Hotspot 1.6.0_27)
1
1024
4294967296
1
1
18014398509481984

Before this patch j3 produces:
1
1024
4294967296
4294967296
4294967296
4294967296

This patch aligns j3 with java's behavior.
Additionally, this causes j3 to pass Mauve's Long tests.
---
 lib/J3/Compiler/JavaJITOpcodes.cpp |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/lib/J3/Compiler/JavaJITOpcodes.cpp
b/lib/J3/Compiler/JavaJITOpcodes.cpp
index 4c5e8cd..93b9c3c 100644
--- a/lib/J3/Compiler/JavaJITOpcodes.cpp
+++ b/lib/J3/Compiler/JavaJITOpcodes.cpp
@@ -1185,6 +1185,8 @@ void JavaJIT::compileOpcodes(Reader& reader,
uint32 codeLength) {

      case LSHL : {
        Value* val2 = new ZExtInst(pop(),
Type::getInt64Ty(*llvmContext), "", currentBlock);
+        Value* mask = ConstantInt::get(Type::getInt64Ty(*llvmContext), 0x3F);
+        val2 = BinaryOperator::CreateAnd(val2, mask, "", currentBlock);
        pop(); // remove the 0 on the stack
        Value* val1 = pop();
        push(BinaryOperator::CreateShl(val1, val2, "", currentBlock),
--
1.7.5.1