Revision: 12831
Author: [email protected]
Date: Mon Oct 29 08:10:21 2012
Log: MIPS: Cleanup handling of shifts: SHR can deoptimize only when
its a shift by 0, all other shift never deoptimize.
Port r12373 (9fdde2ad)
Original commit message:
Fix DoDeferredNumberTagU to keep the value in xmm1 instead of xmm0 on x64.
xmm0 is not saved across runtime call on x64 because
MacroAssembler::EnterExitFrameEpilogue preserves only allocatable XMM
registers unlike on ia32 where it preserves all registers.
Cleanup handling of shifts: SHR can deoptimize only when its a shift by 0,
all other shift never deoptimize.
Fix type inference for i-to-t change instruction. On X64 this ensures that
write-barrier is generated correctly.
BUG=
TEST=
Review URL: https://chromiumcodereview.appspot.com/10876054
Patch from Akos Palfi <[email protected]>.
http://code.google.com/p/v8/source/detail?r=12831
Modified:
/branches/bleeding_edge/src/mips/lithium-mips.cc
=======================================
--- /branches/bleeding_edge/src/mips/lithium-mips.cc Fri Oct 19 05:39:59
2012
+++ /branches/bleeding_edge/src/mips/lithium-mips.cc Mon Oct 29 08:10:21
2012
@@ -702,15 +702,13 @@
right = UseRegisterAtStart(right_value);
}
+ // Shift operations can only deoptimize if we do a logical shift
+ // by 0 and the result cannot be truncated to int32.
bool does_deopt = false;
-
- if (FLAG_opt_safe_uint32_operations) {
- does_deopt = !instr->CheckFlag(HInstruction::kUint32);
- } else {
- // Shift operations can only deoptimize if we do a logical shift
- // by 0 and the result cannot be truncated to int32.
- bool may_deopt = (op == Token::SHR && constant_value == 0);
- if (may_deopt) {
+ if (op == Token::SHR && constant_value == 0) {
+ if (FLAG_opt_safe_uint32_operations) {
+ does_deopt = !instr->CheckFlag(HInstruction::kUint32);
+ } else {
for (HUseIterator it(instr->uses()); !it.Done(); it.Advance()) {
if (!it.value()->CheckFlag(HValue::kTruncatingToInt32)) {
does_deopt = true;
--
v8-dev mailing list
[email protected]
http://groups.google.com/group/v8-dev
