Changeset 96436 in webkit

Timestamp:

Sep 30, 2011 4:05:59 PM (13 years ago)

Author:

barraclough@apple.com

Message:

DFG JIT, Branch on integer can always be a 32-bit compare.
​https://bugs.webkit.org/show_bug.cgi?id=69174

Reviewed by Sam Weinig.

if (shouldSpeculateInteger(node.child1()) && !isStrictInt32(node.child1())),
the JSVALUE64 JIT will currently compare all 64bits in the register, but in
these cases the DataFormat is always a JS boxed integer. In these cases we
can just compare the low 32bits anyway - no need to check the tag.
This allows the code to be unified with the JSVALUE32_64 JIT.

• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• dfg/DFGSpeculativeJIT32_64.cpp (modified) (1 diff)
• dfg/DFGSpeculativeJIT64.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-09-30  Gavin Barraclough  <barraclough@apple.com>
+
+        DFG JIT, Branch on integer can always be a 32-bit compare.
+        https://bugs.webkit.org/show_bug.cgi?id=69174
+
+        Reviewed by Sam Weinig.
+
+        if (shouldSpeculateInteger(node.child1()) && !isStrictInt32(node.child1())),
+        the JSVALUE64 JIT will currently compare all 64bits in the register, but in
+        these cases the DataFormat is always a JS boxed integer. In these cases we
+        can just compare the low 32bits anyway - no need to check the tag.
+        This allows the code to be unified with the JSVALUE32_64 JIT.
+
+        * dfg/DFGSpeculativeJIT32_64.cpp:
+        (JSC::DFG::SpeculativeJIT::compile):
+        * dfg/DFGSpeculativeJIT64.cpp:
+        (JSC::DFG::SpeculativeJIT::compile):
+
 2011-09-30  Oliver Hunt  <oliver@apple.com>
 

trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT32_64.cpp

@@ -1271 +1271 @@
     case Branch:
         if (isStrictInt32(node.child1()) || shouldSpeculateInteger(node.child1())) {
-            SpeculateStrictInt32Operand op(this, node.child1());
+            SpeculateIntegerOperand op(this, node.child1());
             
             BlockIndex taken = m_jit.graph().blockIndexForBytecodeOffset(node.takenBytecodeOffset());

trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT64.cpp

@@ -1364 +1364 @@
 
     case Branch:
-        if (isStrictInt32(node.child1())) {
-            SpeculateStrictInt32Operand op(this, node.child1());
+        if (isStrictInt32(node.child1()) || shouldSpeculateInteger(node.child1())) {
+            SpeculateIntegerOperand op(this, node.child1());
             
             BlockIndex taken = m_jit.graph().blockIndexForBytecodeOffset(node.takenBytecodeOffset());
@@ -1380 +1380 @@
             
             addBranch(m_jit.branchTest32(condition, op.gpr()), taken);
-            if (notTaken != (m_block + 1))
-                addBranch(m_jit.jump(), notTaken);
-            
-            noResult(m_compileIndex);
-            break;
-        }
-        if (shouldSpeculateInteger(node.child1())) {
-            SpeculateIntegerOperand op(this, node.child1());
-
-            BlockIndex taken = m_jit.graph().blockIndexForBytecodeOffset(node.takenBytecodeOffset());
-            BlockIndex notTaken = m_jit.graph().blockIndexForBytecodeOffset(node.notTakenBytecodeOffset());
-            
-            MacroAssembler::RelationalCondition condition = MacroAssembler::NotEqual;
-
-            if (taken == (m_block + 1)) {
-                condition = MacroAssembler::Equal;
-                BlockIndex tmp = taken;
-                taken = notTaken;
-                notTaken = tmp;
-            }
-            
-            addBranch(m_jit.branchPtr(condition, op.gpr(), GPRInfo::tagTypeNumberRegister), taken);
-
             if (notTaken != (m_block + 1))
                 addBranch(m_jit.jump(), notTaken);