Revision: 24619
Author: [email protected]
Date: Wed Oct 15 09:05:40 2014 UTC
Log: [x86] Several small performance improvements.
- Generate
cmp reg, 0
instead of
test reg, -1
for word tests.
- Generate
mov reg, [stack slot]
add reg, reg
jo label
instead of
mov reg, [stack slot]
add reg, [stack slot]
jo label
for SMI tagging.
- Improve materialization of int32 constants on X86-64.
- Branch fusion fix for Word64And and Int64Sub on X86-64.
[email protected]
Review URL: https://codereview.chromium.org/651383003
https://code.google.com/p/v8/source/detail?r=24619
Modified:
/branches/bleeding_edge/src/compiler/ia32/instruction-selector-ia32.cc
/branches/bleeding_edge/src/compiler/x64/code-generator-x64.cc
/branches/bleeding_edge/src/compiler/x64/instruction-selector-x64.cc
=======================================
--- /branches/bleeding_edge/src/compiler/ia32/instruction-selector-ia32.cc
Tue Oct 14 11:57:06 2014 UTC
+++ /branches/bleeding_edge/src/compiler/ia32/instruction-selector-ia32.cc
Wed Oct 15 09:05:40 2014 UTC
@@ -259,7 +259,18 @@
size_t output_count = 0;
// TODO(turbofan): match complex addressing modes.
- if (g.CanBeImmediate(right)) {
+ if (left == right) {
+ // If both inputs refer to the same operand, enforce allocating a
register
+ // for both of them to ensure that we don't end up generating code like
+ // this:
+ //
+ // mov eax, [ebp-0x10]
+ // add eax, [ebp-0x10]
+ // jo label
+ InstructionOperand* const input = g.UseRegister(left);
+ inputs[input_count++] = input;
+ inputs[input_count++] = input;
+ } else if (g.CanBeImmediate(right)) {
inputs[input_count++] = g.UseRegister(left);
inputs[input_count++] = g.UseImmediate(right);
} else {
@@ -672,13 +683,6 @@
VisitCompare(selector, opcode, g.UseRegister(left), g.Use(right),
cont);
}
}
-
-
-static void VisitWordTest(InstructionSelector* selector, Node* node,
- FlagsContinuation* cont) {
- IA32OperandGenerator g(selector);
- VisitCompare(selector, kIA32Test, g.Use(node), g.TempImmediate(-1),
cont);
-}
// Shared routine for multiple float compare operations.
@@ -694,7 +698,7 @@
void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
BasicBlock* fbranch) {
- OperandGenerator g(this);
+ IA32OperandGenerator g(this);
Node* user = branch;
Node* value = branch->InputAt(0);
@@ -780,7 +784,7 @@
}
// Branch could not be combined with a compare, emit compare against 0.
- VisitWordTest(this, value, &cont);
+ VisitCompare(this, kIA32Cmp, g.Use(value), g.TempImmediate(0), &cont);
}
@@ -799,7 +803,6 @@
default:
break;
}
- return VisitWordTest(this, value, &cont);
}
}
return VisitWordCompare(this, node, kIA32Cmp, &cont, false);
=======================================
--- /branches/bleeding_edge/src/compiler/x64/code-generator-x64.cc Tue Oct
14 11:57:06 2014 UTC
+++ /branches/bleeding_edge/src/compiler/x64/code-generator-x64.cc Wed Oct
15 09:05:40 2014 UTC
@@ -870,7 +870,7 @@
switch (src.type()) {
case Constant::kInt32:
// TODO(dcarney): don't need scratch in this case.
- __ movq(dst, Immediate(src.ToInt32()));
+ __ Set(dst, src.ToInt32());
break;
case Constant::kInt64:
__ Set(dst, src.ToInt64());
=======================================
--- /branches/bleeding_edge/src/compiler/x64/instruction-selector-x64.cc
Tue Oct 14 11:57:06 2014 UTC
+++ /branches/bleeding_edge/src/compiler/x64/instruction-selector-x64.cc
Wed Oct 15 09:05:40 2014 UTC
@@ -240,7 +240,18 @@
size_t output_count = 0;
// TODO(turbofan): match complex addressing modes.
- if (g.CanBeImmediate(right)) {
+ if (left == right) {
+ // If both inputs refer to the same operand, enforce allocating a
register
+ // for both of them to ensure that we don't end up generating code like
+ // this:
+ //
+ // mov rax, [rbp-0x10]
+ // add rax, [rbp-0x10]
+ // jo label
+ InstructionOperand* const input = g.UseRegister(left);
+ inputs[input_count++] = input;
+ inputs[input_count++] = input;
+ } else if (g.CanBeImmediate(right)) {
inputs[input_count++] = g.UseRegister(left);
inputs[input_count++] = g.UseImmediate(right);
} else {
@@ -794,13 +805,6 @@
VisitCompare(selector, opcode, g.UseRegister(left), g.Use(right),
cont);
}
}
-
-
-static void VisitWordTest(InstructionSelector* selector, Node* node,
- InstructionCode opcode, FlagsContinuation* cont)
{
- X64OperandGenerator g(selector);
- VisitCompare(selector, opcode, g.Use(node), g.TempImmediate(-1), cont);
-}
static void VisitFloat64Compare(InstructionSelector* selector, Node* node,
@@ -815,7 +819,7 @@
void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
BasicBlock* fbranch) {
- OperandGenerator g(this);
+ X64OperandGenerator g(this);
Node* user = branch;
Node* value = branch->InputAt(0);
@@ -918,15 +922,19 @@
break;
case IrOpcode::kInt32Sub:
return VisitWordCompare(this, value, kX64Cmp32, &cont, false);
+ case IrOpcode::kInt64Sub:
+ return VisitWordCompare(this, value, kX64Cmp, &cont, false);
case IrOpcode::kWord32And:
return VisitWordCompare(this, value, kX64Test32, &cont, true);
+ case IrOpcode::kWord64And:
+ return VisitWordCompare(this, value, kX64Test, &cont, true);
default:
break;
}
}
// Branch could not be combined with a compare, emit compare against 0.
- VisitWordTest(this, value, kX64Test32, &cont);
+ VisitCompare(this, kX64Cmp32, g.Use(value), g.TempImmediate(0), &cont);
}
@@ -945,7 +953,6 @@
default:
break;
}
- return VisitWordTest(this, value, kX64Test32, &cont);
}
}
VisitWordCompare(this, node, kX64Cmp32, &cont, false);
@@ -991,7 +998,6 @@
default:
break;
}
- return VisitWordTest(this, value, kX64Test, &cont);
}
}
VisitWordCompare(this, node, kX64Cmp, &cont, false);
--
--
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