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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/196433">196433</a></dd>
<dt>Author</dt> <dd>fpizlo@apple.com</dd>
<dt>Date</dt> <dd>2016-02-11 13:22:02 -0800 (Thu, 11 Feb 2016)</dd>
</dl>
<h3>Log Message</h3>
<pre>MacroAssemblerX86 should be happy with shift(cx, cx)
https://bugs.webkit.org/show_bug.cgi?id=154124
Reviewed by Saam Barati.
Prior to this change the assembler asserted that shift_amount and dest cannot be the same.
That's a good assertion for when shift_amount is not in cx. But if it's in cx already then
it's OK for them to be the same. Air will sometimes do shift(cx, cx) if you do "x << x" and
the coalescing got particularly clever.
* assembler/MacroAssemblerX86Common.h:
(JSC::MacroAssemblerX86Common::lshift32):
(JSC::MacroAssemblerX86Common::rshift32):
(JSC::MacroAssemblerX86Common::urshift32):
* assembler/MacroAssemblerX86_64.h:
(JSC::MacroAssemblerX86_64::lshift64):
(JSC::MacroAssemblerX86_64::rshift64):
(JSC::MacroAssemblerX86_64::urshift64):
* b3/testb3.cpp:
(JSC::B3::testLShiftSelf32):
(JSC::B3::testRShiftSelf32):
(JSC::B3::testURShiftSelf32):
(JSC::B3::testLShiftSelf64):
(JSC::B3::testRShiftSelf64):
(JSC::B3::testURShiftSelf64):
(JSC::B3::run):</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceJavaScriptCoreChangeLog">trunk/Source/JavaScriptCore/ChangeLog</a></li>
<li><a href="#trunkSourceJavaScriptCoreassemblerMacroAssemblerX86Commonh">trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h</a></li>
<li><a href="#trunkSourceJavaScriptCoreassemblerMacroAssemblerX86_64h">trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86_64.h</a></li>
<li><a href="#trunkSourceJavaScriptCoreb3testb3cpp">trunk/Source/JavaScriptCore/b3/testb3.cpp</a></li>
</ul>
</div>
<div id="patch">
<h3>Diff</h3>
<a id="trunkSourceJavaScriptCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/ChangeLog (196432 => 196433)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/ChangeLog 2016-02-11 21:04:43 UTC (rev 196432)
+++ trunk/Source/JavaScriptCore/ChangeLog 2016-02-11 21:22:02 UTC (rev 196433)
</span><span class="lines">@@ -1,3 +1,32 @@
</span><ins>+2016-02-11 Filip Pizlo <fpizlo@apple.com>
+
+ MacroAssemblerX86 should be happy with shift(cx, cx)
+ https://bugs.webkit.org/show_bug.cgi?id=154124
+
+ Reviewed by Saam Barati.
+
+ Prior to this change the assembler asserted that shift_amount and dest cannot be the same.
+ That's a good assertion for when shift_amount is not in cx. But if it's in cx already then
+ it's OK for them to be the same. Air will sometimes do shift(cx, cx) if you do "x << x" and
+ the coalescing got particularly clever.
+
+ * assembler/MacroAssemblerX86Common.h:
+ (JSC::MacroAssemblerX86Common::lshift32):
+ (JSC::MacroAssemblerX86Common::rshift32):
+ (JSC::MacroAssemblerX86Common::urshift32):
+ * assembler/MacroAssemblerX86_64.h:
+ (JSC::MacroAssemblerX86_64::lshift64):
+ (JSC::MacroAssemblerX86_64::rshift64):
+ (JSC::MacroAssemblerX86_64::urshift64):
+ * b3/testb3.cpp:
+ (JSC::B3::testLShiftSelf32):
+ (JSC::B3::testRShiftSelf32):
+ (JSC::B3::testURShiftSelf32):
+ (JSC::B3::testLShiftSelf64):
+ (JSC::B3::testRShiftSelf64):
+ (JSC::B3::testURShiftSelf64):
+ (JSC::B3::run):
+
</ins><span class="cx"> 2016-02-11 Saam barati <sbarati@apple.com>
</span><span class="cx">
</span><span class="cx"> The sampling profiler's stack walker methods should be marked with SUPPRESS_ASAN
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreassemblerMacroAssemblerX86Commonh"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h (196432 => 196433)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h 2016-02-11 21:04:43 UTC (rev 196432)
+++ trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86Common.h 2016-02-11 21:22:02 UTC (rev 196433)
</span><span class="lines">@@ -295,11 +295,10 @@
</span><span class="cx">
</span><span class="cx"> void lshift32(RegisterID shift_amount, RegisterID dest)
</span><span class="cx"> {
</span><del>- ASSERT(shift_amount != dest);
-
</del><span class="cx"> if (shift_amount == X86Registers::ecx)
</span><span class="cx"> m_assembler.shll_CLr(dest);
</span><span class="cx"> else {
</span><ins>+ ASSERT(shift_amount != dest);
</ins><span class="cx"> // On x86 we can only shift by ecx; if asked to shift by another register we'll
</span><span class="cx"> // need rejig the shift amount into ecx first, and restore the registers afterwards.
</span><span class="cx"> // If we dest is ecx, then shift the swapped register!
</span><span class="lines">@@ -424,11 +423,11 @@
</span><span class="cx">
</span><span class="cx"> void rshift32(RegisterID shift_amount, RegisterID dest)
</span><span class="cx"> {
</span><del>- ASSERT(shift_amount != dest);
-
</del><span class="cx"> if (shift_amount == X86Registers::ecx)
</span><span class="cx"> m_assembler.sarl_CLr(dest);
</span><span class="cx"> else {
</span><ins>+ ASSERT(shift_amount != dest);
+
</ins><span class="cx"> // On x86 we can only shift by ecx; if asked to shift by another register we'll
</span><span class="cx"> // need rejig the shift amount into ecx first, and restore the registers afterwards.
</span><span class="cx"> // If we dest is ecx, then shift the swapped register!
</span><span class="lines">@@ -461,11 +460,11 @@
</span><span class="cx">
</span><span class="cx"> void urshift32(RegisterID shift_amount, RegisterID dest)
</span><span class="cx"> {
</span><del>- ASSERT(shift_amount != dest);
-
</del><span class="cx"> if (shift_amount == X86Registers::ecx)
</span><span class="cx"> m_assembler.shrl_CLr(dest);
</span><span class="cx"> else {
</span><ins>+ ASSERT(shift_amount != dest);
+
</ins><span class="cx"> // On x86 we can only shift by ecx; if asked to shift by another register we'll
</span><span class="cx"> // need rejig the shift amount into ecx first, and restore the registers afterwards.
</span><span class="cx"> // If we dest is ecx, then shift the swapped register!
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreassemblerMacroAssemblerX86_64h"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86_64.h (196432 => 196433)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86_64.h 2016-02-11 21:04:43 UTC (rev 196432)
+++ trunk/Source/JavaScriptCore/assembler/MacroAssemblerX86_64.h 2016-02-11 21:22:02 UTC (rev 196433)
</span><span class="lines">@@ -376,11 +376,11 @@
</span><span class="cx">
</span><span class="cx"> void lshift64(RegisterID src, RegisterID dest)
</span><span class="cx"> {
</span><del>- ASSERT(src != dest);
-
</del><span class="cx"> if (src == X86Registers::ecx)
</span><span class="cx"> m_assembler.shlq_CLr(dest);
</span><span class="cx"> else {
</span><ins>+ ASSERT(src != dest);
+
</ins><span class="cx"> // Can only shift by ecx, so we do some swapping if we see anything else.
</span><span class="cx"> swap(src, X86Registers::ecx);
</span><span class="cx"> m_assembler.shlq_CLr(dest);
</span><span class="lines">@@ -395,11 +395,11 @@
</span><span class="cx">
</span><span class="cx"> void rshift64(RegisterID src, RegisterID dest)
</span><span class="cx"> {
</span><del>- ASSERT(src != dest);
-
</del><span class="cx"> if (src == X86Registers::ecx)
</span><span class="cx"> m_assembler.sarq_CLr(dest);
</span><span class="cx"> else {
</span><ins>+ ASSERT(src != dest);
+
</ins><span class="cx"> // Can only shift by ecx, so we do some swapping if we see anything else.
</span><span class="cx"> swap(src, X86Registers::ecx);
</span><span class="cx"> m_assembler.sarq_CLr(dest);
</span><span class="lines">@@ -414,11 +414,11 @@
</span><span class="cx">
</span><span class="cx"> void urshift64(RegisterID src, RegisterID dest)
</span><span class="cx"> {
</span><del>- ASSERT(src != dest);
-
</del><span class="cx"> if (src == X86Registers::ecx)
</span><span class="cx"> m_assembler.shrq_CLr(dest);
</span><span class="cx"> else {
</span><ins>+ ASSERT(src != dest);
+
</ins><span class="cx"> // Can only shift by ecx, so we do some swapping if we see anything else.
</span><span class="cx"> swap(src, X86Registers::ecx);
</span><span class="cx"> m_assembler.shrq_CLr(dest);
</span></span></pre></div>
<a id="trunkSourceJavaScriptCoreb3testb3cpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/JavaScriptCore/b3/testb3.cpp (196432 => 196433)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/JavaScriptCore/b3/testb3.cpp 2016-02-11 21:04:43 UTC (rev 196432)
+++ trunk/Source/JavaScriptCore/b3/testb3.cpp 2016-02-11 21:22:02 UTC (rev 196433)
</span><span class="lines">@@ -10065,6 +10065,147 @@
</span><span class="cx"> CHECK(invoke<intptr_t>(*code, 42) == 0);
</span><span class="cx"> }
</span><span class="cx">
</span><ins>+void testLShiftSelf32()
+{
+ Procedure proc;
+ BasicBlock* root = proc.addBlock();
+ Value* arg = root->appendNew<Value>(
+ proc, Trunc, Origin(),
+ root->appendNew<ArgumentRegValue>(proc, Origin(), GPRInfo::argumentGPR0));
+ root->appendNew<ControlValue>(
+ proc, Return, Origin(),
+ root->appendNew<Value>(proc, Shl, Origin(), arg, arg));
+
+ auto code = compile(proc);
+
+ auto check = [&] (int32_t value) {
+ CHECK(invoke<int32_t>(*code, value) == value << (value & 31));
+ };
+
+ check(0);
+ check(1);
+ check(31);
+ check(32);
+}
+
+void testRShiftSelf32()
+{
+ Procedure proc;
+ BasicBlock* root = proc.addBlock();
+ Value* arg = root->appendNew<Value>(
+ proc, Trunc, Origin(),
+ root->appendNew<ArgumentRegValue>(proc, Origin(), GPRInfo::argumentGPR0));
+ root->appendNew<ControlValue>(
+ proc, Return, Origin(),
+ root->appendNew<Value>(proc, SShr, Origin(), arg, arg));
+
+ auto code = compile(proc);
+
+ auto check = [&] (int32_t value) {
+ CHECK(invoke<int32_t>(*code, value) == value >> (value & 31));
+ };
+
+ check(0);
+ check(1);
+ check(31);
+ check(32);
+}
+
+void testURShiftSelf32()
+{
+ Procedure proc;
+ BasicBlock* root = proc.addBlock();
+ Value* arg = root->appendNew<Value>(
+ proc, Trunc, Origin(),
+ root->appendNew<ArgumentRegValue>(proc, Origin(), GPRInfo::argumentGPR0));
+ root->appendNew<ControlValue>(
+ proc, Return, Origin(),
+ root->appendNew<Value>(proc, ZShr, Origin(), arg, arg));
+
+ auto code = compile(proc);
+
+ auto check = [&] (uint32_t value) {
+ CHECK(invoke<uint32_t>(*code, value) == value >> (value & 31));
+ };
+
+ check(0);
+ check(1);
+ check(31);
+ check(32);
+}
+
+void testLShiftSelf64()
+{
+ Procedure proc;
+ BasicBlock* root = proc.addBlock();
+ Value* arg = root->appendNew<ArgumentRegValue>(proc, Origin(), GPRInfo::argumentGPR0);
+ root->appendNew<ControlValue>(
+ proc, Return, Origin(),
+ root->appendNew<Value>(
+ proc, Shl, Origin(), arg, root->appendNew<Value>(proc, Trunc, Origin(), arg)));
+
+ auto code = compile(proc);
+
+ auto check = [&] (int64_t value) {
+ CHECK(invoke<int64_t>(*code, value) == value << (value & 63));
+ };
+
+ check(0);
+ check(1);
+ check(31);
+ check(32);
+ check(63);
+ check(64);
+}
+
+void testRShiftSelf64()
+{
+ Procedure proc;
+ BasicBlock* root = proc.addBlock();
+ Value* arg = root->appendNew<ArgumentRegValue>(proc, Origin(), GPRInfo::argumentGPR0);
+ root->appendNew<ControlValue>(
+ proc, Return, Origin(),
+ root->appendNew<Value>(
+ proc, SShr, Origin(), arg, root->appendNew<Value>(proc, Trunc, Origin(), arg)));
+
+ auto code = compile(proc);
+
+ auto check = [&] (int64_t value) {
+ CHECK(invoke<int64_t>(*code, value) == value >> (value & 63));
+ };
+
+ check(0);
+ check(1);
+ check(31);
+ check(32);
+ check(63);
+ check(64);
+}
+
+void testURShiftSelf64()
+{
+ Procedure proc;
+ BasicBlock* root = proc.addBlock();
+ Value* arg = root->appendNew<ArgumentRegValue>(proc, Origin(), GPRInfo::argumentGPR0);
+ root->appendNew<ControlValue>(
+ proc, Return, Origin(),
+ root->appendNew<Value>(
+ proc, ZShr, Origin(), arg, root->appendNew<Value>(proc, Trunc, Origin(), arg)));
+
+ auto code = compile(proc);
+
+ auto check = [&] (uint64_t value) {
+ CHECK(invoke<uint64_t>(*code, value) == value >> (value & 63));
+ };
+
+ check(0);
+ check(1);
+ check(31);
+ check(32);
+ check(63);
+ check(64);
+}
+
</ins><span class="cx"> // Make sure the compiler does not try to optimize anything out.
</span><span class="cx"> NEVER_INLINE double zero()
</span><span class="cx"> {
</span><span class="lines">@@ -11466,6 +11607,13 @@
</span><span class="cx"> RUN(testComputeDivisionMagic<int32_t>(2, -2147483647, 0));
</span><span class="cx"> RUN(testTrivialInfiniteLoop());
</span><span class="cx"> RUN(testFoldPathEqual());
</span><ins>+
+ RUN(testRShiftSelf32());
+ RUN(testURShiftSelf32());
+ RUN(testLShiftSelf32());
+ RUN(testRShiftSelf64());
+ RUN(testURShiftSelf64());
+ RUN(testLShiftSelf64());
</ins><span class="cx">
</span><span class="cx"> if (tasks.isEmpty())
</span><span class="cx"> usage();
</span></span></pre>
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