Changeset 197654 in webkit

Timestamp:

Mar 6, 2016, 6:43:09 PM (11 years ago)

Author:

benjamin@webkit.org

Message:

[JSC] Remove a superfluous Move in front of every double unboxing
​https://bugs.webkit.org/show_bug.cgi?id=155064

Reviewed by Saam Barati.

Double unboxing was always doing:

Move source, scratch
Add64 tag, scratch
IntToDouble scratch, fp

We do not need to "Move" to copy the source.
Both x86 and ARM64 have an efficient 3 operands Add instruction.

• dfg/DFGSpeculativeJIT.cpp:

(JSC::DFG::SpeculativeJIT::compileValueToInt32):
(JSC::DFG::SpeculativeJIT::compileDoubleRep):
(JSC::DFG::SpeculativeJIT::speculateRealNumber):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::unboxDouble):

• jit/AssemblyHelpers.h:

(JSC::AssemblyHelpers::unboxDoubleWithoutAssertions):
(JSC::AssemblyHelpers::unboxDouble):
(JSC::AssemblyHelpers::unboxDoubleNonDestructive):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• dfg/DFGSpeculativeJIT.cpp (modified) (4 diffs)
• dfg/DFGSpeculativeJIT.h (modified) (1 diff)
• jit/AssemblyHelpers.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2016-03-06  Benjamin Poulain  <benjamin@webkit.org>
+
+        [JSC] Remove a superfluous Move in front of every double unboxing
+        https://bugs.webkit.org/show_bug.cgi?id=155064
+
+        Reviewed by Saam Barati.
+
+        Double unboxing was always doing:
+            Move source, scratch
+            Add64 tag, scratch
+            IntToDouble scratch, fp
+
+        We do not need to "Move" to copy the source.
+        Both x86 and ARM64 have an efficient 3 operands Add instruction.
+
+        * dfg/DFGSpeculativeJIT.cpp:
+        (JSC::DFG::SpeculativeJIT::compileValueToInt32):
+        (JSC::DFG::SpeculativeJIT::compileDoubleRep):
+        (JSC::DFG::SpeculativeJIT::speculateRealNumber):
+        * dfg/DFGSpeculativeJIT.h:
+        (JSC::DFG::SpeculativeJIT::unboxDouble):
+        * jit/AssemblyHelpers.h:
+        (JSC::AssemblyHelpers::unboxDoubleWithoutAssertions):
+        (JSC::AssemblyHelpers::unboxDouble):
+        (JSC::AssemblyHelpers::unboxDoubleNonDestructive):
+
 2016-03-06  Benjamin Poulain  <benjamin@webkit.org>
 

trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.cpp

@@ -2014 +2014 @@
 
             // First, if we get here we have a double encoded as a JSValue
-            m_jit.move(gpr, resultGpr);
-            unboxDouble(resultGpr, fpr);
+            unboxDouble(gpr, resultGpr, fpr);
 
             silentSpillAllRegisters(resultGpr);
@@ -2172 +2171 @@
         GPRTemporary temp(this);
         GPRReg tempGPR = temp.gpr();
-        m_jit.move(op1Regs.gpr(), tempGPR);
-        m_jit.unboxDoubleWithoutAssertions(tempGPR, resultFPR);
+        m_jit.unboxDoubleWithoutAssertions(op1Regs.gpr(), tempGPR, resultFPR);
 #else
         FPRTemporary temp(this);
@@ -2250 +2248 @@
                 m_jit.branchTest64(MacroAssembler::Zero, op1GPR, GPRInfo::tagTypeNumberRegister));
         }
-    
-        m_jit.move(op1GPR, tempGPR);
-        unboxDouble(tempGPR, resultFPR);
+
+        unboxDouble(op1GPR, tempGPR, resultFPR);
         done.append(m_jit.jump());
     
@@ -6584 +6581 @@
     GPRTemporary temp(this);
     GPRReg tempGPR = temp.gpr();
-    m_jit.move(op1Regs.gpr(), tempGPR);
-    m_jit.unboxDoubleWithoutAssertions(tempGPR, resultFPR);
+    m_jit.unboxDoubleWithoutAssertions(op1Regs.gpr(), tempGPR, resultFPR);
 #else
     FPRTemporary temp(this);

trunk/Source/JavaScriptCore/dfg/DFGSpeculativeJIT.h

@@ -453 +453 @@
         return m_jit.boxDouble(fpr, gpr);
     }
-    FPRReg unboxDouble(GPRReg gpr, FPRReg fpr)
-    {
-        return m_jit.unboxDouble(gpr, fpr);
+    FPRReg unboxDouble(GPRReg gpr, GPRReg resultGPR, FPRReg fpr)
+    {
+        return m_jit.unboxDouble(gpr, resultGPR, fpr);
     }
     GPRReg boxDouble(FPRReg fpr)

trunk/Source/JavaScriptCore/jit/AssemblyHelpers.h

@@ -1038 +1038 @@
         return gpr;
     }
-    FPRReg unboxDoubleWithoutAssertions(GPRReg gpr, FPRReg fpr)
-    {
-        add64(GPRInfo::tagTypeNumberRegister, gpr);
-        move64ToDouble(gpr, fpr);
+    FPRReg unboxDoubleWithoutAssertions(GPRReg gpr, GPRReg resultGPR, FPRReg fpr)
+    {
+        add64(GPRInfo::tagTypeNumberRegister, gpr, resultGPR);
+        move64ToDouble(resultGPR, fpr);
         return fpr;
     }
-    FPRReg unboxDouble(GPRReg gpr, FPRReg fpr)
+    FPRReg unboxDouble(GPRReg gpr, GPRReg resultGPR, FPRReg fpr)
     {
         jitAssertIsJSDouble(gpr);
-        return unboxDoubleWithoutAssertions(gpr, fpr);
+        return unboxDoubleWithoutAssertions(gpr, resultGPR, fpr);
     }
     
@@ -1055 +1055 @@
     }
 
-    void unboxDoubleNonDestructive(JSValueRegs regs, FPRReg destFPR, GPRReg scratchGPR, FPRReg)
-    {
-        move(regs.payloadGPR(), scratchGPR);
-        unboxDouble(scratchGPR, destFPR);
+    void unboxDoubleNonDestructive(JSValueRegs regs, FPRReg destFPR, GPRReg resultGPR, FPRReg)
+    {
+        unboxDouble(regs.payloadGPR(), resultGPR, destFPR);
     }