Author: [EMAIL PROTECTED]
Date: Thu Sep 11 08:16:08 2008
New Revision: 286
Modified:
branches/bleeding_edge/src/codegen-arm.cc
branches/bleeding_edge/src/codegen-ia32.cc
Log:
Fix performace regression due to missed peephole optimization
opportunity.
Review URL: http://codereview.chromium.org/2002
Modified: branches/bleeding_edge/src/codegen-arm.cc
==============================================================================
--- branches/bleeding_edge/src/codegen-arm.cc (original)
+++ branches/bleeding_edge/src/codegen-arm.cc Thu Sep 11 08:16:08 2008
@@ -948,6 +948,7 @@
ASSERT(var()->mode() != Variable::DYNAMIC);
Label exit;
+ bool may_skip_write = false;
if (init_state == CONST_INIT) {
ASSERT(var()->mode() == Variable::CONST);
// Only the first const initialization must be executed (the slot
@@ -957,6 +958,7 @@
masm->ldr(r2, ArmCodeGenerator::SlotOperand(masm, scope, this, r2));
masm->cmp(r2, Operand(Factory::the_hole_value()));
masm->b(ne, &exit);
+ may_skip_write = true;
}
// We must execute the store.
@@ -981,7 +983,9 @@
masm->mov(r3, Operand(offset));
masm->RecordWrite(r2, r3, r1);
}
- masm->bind(&exit);
+ // If we definitely did not jump over the assignment, we do not need to
+ // bind the exit label. Doing so can defeat peephole optimization.
+ if (may_skip_write) masm->bind(&exit);
}
}
Modified: branches/bleeding_edge/src/codegen-ia32.cc
==============================================================================
--- branches/bleeding_edge/src/codegen-ia32.cc (original)
+++ branches/bleeding_edge/src/codegen-ia32.cc Thu Sep 11 08:16:08 2008
@@ -975,6 +975,7 @@
ASSERT(var()->mode() != Variable::DYNAMIC);
Label exit;
+ bool may_skip_write = false;
if (init_state == CONST_INIT) {
ASSERT(var()->mode() == Variable::CONST);
// Only the first const initialization must be executed (the slot
@@ -984,6 +985,7 @@
masm->mov(eax, Ia32CodeGenerator::SlotOperand(masm, scope, this,
ecx));
masm->cmp(eax, Factory::the_hole_value());
masm->j(not_equal, &exit);
+ may_skip_write = true;
}
// We must execute the store.
@@ -1003,7 +1005,9 @@
int offset = FixedArray::kHeaderSize + index() * kPointerSize;
masm->RecordWrite(ecx, offset, eax, ebx);
}
- masm->bind(&exit);
+ // If we definitely did not jump over the assignment, we do not need to
+ // bind the exit label. Doing so can defeat peephole optimization.
+ if (may_skip_write) masm->bind(&exit);
}
}
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