Revision: 14383
Author: [email protected]
Date: Mon Apr 22 15:45:34 2013
Log: MIPS: Improvements in lithium code generation. Recognizing if
some operands are constants, we can often save on registers and
instructions.
Port r14364 (2819e5ee)
BUG=
Review URL: https://codereview.chromium.org/14159015
http://code.google.com/p/v8/source/detail?r=14383
Modified:
/branches/bleeding_edge/src/mips/lithium-codegen-mips.cc
/branches/bleeding_edge/src/mips/lithium-mips.cc
=======================================
--- /branches/bleeding_edge/src/mips/lithium-codegen-mips.cc Mon Apr 22
02:48:35 2013
+++ /branches/bleeding_edge/src/mips/lithium-codegen-mips.cc Mon Apr 22
15:45:34 2013
@@ -2873,16 +2873,24 @@
void LCodeGen::DoAccessArgumentsAt(LAccessArgumentsAt* instr) {
Register arguments = ToRegister(instr->arguments());
- Register length = ToRegister(instr->length());
- Register index = ToRegister(instr->index());
Register result = ToRegister(instr->result());
- // There are two words between the frame pointer and the last argument.
- // Subtracting from length accounts for one of them, add one more.
- __ subu(length, length, index);
- __ Addu(length, length, Operand(1));
- __ sll(length, length, kPointerSizeLog2);
- __ Addu(at, arguments, Operand(length));
- __ lw(result, MemOperand(at, 0));
+ if (instr->length()->IsConstantOperand() &&
+ instr->index()->IsConstantOperand()) {
+ int const_index = ToInteger32(LConstantOperand::cast(instr->index()));
+ int const_length =
ToInteger32(LConstantOperand::cast(instr->length()));
+ int index = (const_length - const_index) + 1;
+ __ lw(result, MemOperand(arguments, index * kPointerSize));
+ } else {
+ Register length = ToRegister(instr->length());
+ Register index = ToRegister(instr->index());
+ // There are two words between the frame pointer and the last argument.
+ // Subtracting from length accounts for one of them, add one more.
+ __ subu(length, length, index);
+ __ Addu(length, length, Operand(1));
+ __ sll(length, length, kPointerSizeLog2);
+ __ Addu(at, arguments, Operand(length));
+ __ lw(result, MemOperand(at, 0));
+ }
}
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.cc Mon Apr 22 02:48:35
2013
+++ /branches/bleeding_edge/src/mips/lithium-mips.cc Mon Apr 22 15:45:34
2013
@@ -2340,8 +2340,15 @@
LInstruction* LChunkBuilder::DoAccessArgumentsAt(HAccessArgumentsAt*
instr) {
info()->MarkAsRequiresFrame();
LOperand* args = UseRegister(instr->arguments());
- LOperand* length = UseTempRegister(instr->length());
- LOperand* index = UseRegister(instr->index());
+ LOperand* length;
+ LOperand* index;
+ if (instr->length()->IsConstant() && instr->index()->IsConstant()) {
+ length = UseRegisterOrConstant(instr->length());
+ index = UseOrConstant(instr->index());
+ } else {
+ length = UseTempRegister(instr->length());
+ index = Use(instr->index());
+ }
return DefineAsRegister(new(zone()) LAccessArgumentsAt(args, length,
index));
}
--
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
---
You received this message because you are subscribed to the Google Groups "v8-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/groups/opt_out.
