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[turbofan][x64][ptr-compr] Use root register for kHeapConstant equality

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VisitWord32EqualImpl was checking for inputs of type
kCompressedHeapConstant, but it can also sometimes have inputs of type
kHeapConstant. In either case, we can check for whether to do a load
from the roots array. This improves Octane score by about 3% (or about
1.5% if --no-opt is specified).

Bug: v8:8948
Change-Id: Iab6c0b1dacd96c74e4cfb54c772aa92e5baf00ff
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2213081
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67981}
This commit is contained in:
Seth Brenith 2020-05-26 08:56:05 -07:00 committed by Commit Bot
parent 2bf94b8699
commit 02acf4a005
1 changed files with 21 additions and 4 deletions
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23
src/compiler/backend/x64/instruction-selector-x64.cc
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@ -1898,16 +1898,33 @@ void VisitWord32EqualImpl(InstructionSelector* selector, Node* node,
X64OperandGenerator g(selector);
const RootsTable& roots_table = selector->isolate()->roots_table();
RootIndex root_index;
Node* left = nullptr;
Handle<HeapObject> right;
// HeapConstants and CompressedHeapConstants can be treated the same when
// using them as an input to a 32-bit comparison. Check whether either is
// present.
{
CompressedHeapObjectBinopMatcher m(node);
if (m.right().HasValue() &&
roots_table.IsRootHandle(m.right().Value(), &root_index)) {
if (m.right().HasValue()) {
left = m.left().node();
right = m.right().Value();
} else {
HeapObjectBinopMatcher m2(node);
if (m2.right().HasValue()) {
left = m2.left().node();
right = m2.right().Value();
}
}
}
if (!right.is_null() && roots_table.IsRootHandle(right, &root_index)) {
DCHECK_NE(left, nullptr);
InstructionCode opcode =
kX64Cmp32 | AddressingModeField::encode(kMode_Root);
return VisitCompare(
selector, opcode,
g.TempImmediate(
TurboAssemblerBase::RootRegisterOffsetForRootIndex(root_index)),
g.UseRegister(m.left().node()), cont);
g.UseRegister(left), cont);
}
}
VisitWordCompare(selector, node, kX64Cmp32, cont);