Reviewers: Sven Panne,
Message:
Hi Sven,
Here is a fix for the issue you discovered in the DXT5Decoder test. The
issue
was that I needed to be more careful in preserving register allocation
decisions. Here, register pressure was increased unnecessarily.
Description:
Fix performance regression in DXT5Decoder.js.
[email protected]
BUG=
Please review this at https://codereview.chromium.org/11412129/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/x64/lithium-x64.cc
Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index
45b15723dc7ac856ee6c7b19be4c7ea6ec524af9..c345e764564ef9d36851908476dbbb7a75c1d481
100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1887,26 +1887,27 @@ LInstruction*
LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
ElementsKind elements_kind = instr->elements_kind();
bool needs_write_barrier = instr->NeedsWriteBarrier();
bool clobbers_key = instr->key()->representation().IsTagged();
- LOperand* key = (clobbers_key || needs_write_barrier)
- ? UseTempRegister(instr->key())
- : UseRegisterOrConstantAtStart(instr->key());
- bool val_is_temp_register =
- elements_kind == EXTERNAL_PIXEL_ELEMENTS ||
- elements_kind == EXTERNAL_FLOAT_ELEMENTS;
- LOperand* val = (needs_write_barrier || val_is_temp_register)
- ? UseTempRegister(instr->value())
- : UseRegisterAtStart(instr->value());
LStoreKeyed* result = NULL;
if (!instr->is_external()) {
ASSERT(instr->elements()->representation().IsTagged());
LOperand* object = NULL;
+ LOperand* key = NULL;
+ LOperand* val = NULL;
if (instr->value()->representation().IsDouble()) {
object = UseRegisterAtStart(instr->elements());
+ val = UseTempRegister(instr->value());
+ key = clobbers_key ? UseTempRegister(instr->key())
+ : UseRegisterOrConstantAtStart(instr->key());
} else {
ASSERT(instr->value()->representation().IsTagged());
object = UseTempRegister(instr->elements());
+ val = needs_write_barrier ? UseTempRegister(instr->value())
+ : UseRegisterAtStart(instr->value());
+ key = (clobbers_key || needs_write_barrier)
+ ? UseTempRegister(instr->key())
+ : UseRegisterOrConstantAtStart(instr->key());
}
result = new(zone()) LStoreKeyed(object, key, val);
@@ -1919,7 +1920,13 @@ LInstruction*
LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
((elements_kind == EXTERNAL_FLOAT_ELEMENTS) ||
(elements_kind == EXTERNAL_DOUBLE_ELEMENTS))));
ASSERT(instr->elements()->representation().IsExternal());
-
+ bool val_is_temp_register =
+ elements_kind == EXTERNAL_PIXEL_ELEMENTS ||
+ elements_kind == EXTERNAL_FLOAT_ELEMENTS;
+ LOperand* val = val_is_temp_register ? UseTempRegister(instr->value())
+ : UseRegister(instr->value());
+ LOperand* key = clobbers_key ? UseTempRegister(instr->key())
+ : UseRegisterOrConstantAtStart(instr->key());
LOperand* external_pointer = UseRegister(instr->elements());
result = new(zone()) LStoreKeyed(external_pointer, key, val);
}
--
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