From cca2e1943106fe78dc80882a053d7559e763a356 Mon Sep 17 00:00:00 2001
From: Erik Verbruggen <erik.verbruggen@qt.io>
Date: Tue, 7 Nov 2017 12:34:15 +0100
Subject: V4: Add int32 fastpath for inc/dec

Change-Id: I276793a2fc4a253e5ec35e7f04a1032f23a03bad
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 src/qml/jit/qv4assembler.cpp | 55 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 4 deletions(-)

(limited to 'src/qml')

diff --git a/src/qml/jit/qv4assembler.cpp b/src/qml/jit/qv4assembler.cpp
index e357211074..d79739fad5 100644
--- a/src/qml/jit/qv4assembler.cpp
+++ b/src/qml/jit/qv4assembler.cpp
@@ -822,6 +822,23 @@ struct PlatformAssembler64 : PlatformAssemblerCommon
 
         return done;
     }
+
+    Jump unopIntPath(std::function<Jump(void)> fastPath)
+    {
+        urshift64(AccumulatorRegister, TrustedImm32(32), ScratchRegister);
+        Jump accNotInt = branch32(NotEqual, TrustedImm32(int(IntegerTag)), ScratchRegister);
+
+        // both integer
+        Jump failure = fastPath();
+        Jump done = jump();
+
+        // all other cases
+        if (failure.isSet())
+            failure.link(this);
+        accNotInt.link(this);
+
+        return done;
+    }
 };
 
 typedef PlatformAssembler64 PlatformAssembler;
@@ -1098,6 +1115,22 @@ struct PlatformAssembler32 : PlatformAssemblerCommon
 
         return done;
     }
+
+    Jump unopIntPath(std::function<Jump(void)> fastPath)
+    {
+        Jump accNotInt = branch32(NotEqual, TrustedImm32(int(IntegerTag)), AccumulatorRegisterTag);
+
+        // both integer
+        Jump failure = fastPath();
+        Jump done = jump();
+
+        // all other cases
+        if (failure.isSet())
+            failure.link(this);
+        accNotInt.link(this);
+
+        return done;
+    }
 };
 
 typedef PlatformAssembler32 PlatformAssembler;
@@ -1300,7 +1333,14 @@ static ReturnedValue incHelper(const Value &v)
 
 void Assembler::inc()
 {
-//    auto done = pasm()->incFastPath();
+    auto done = pasm()->unopIntPath([this](){
+        auto overflowed = pasm()->branchAdd32(PlatformAssembler::Overflow,
+                                              PlatformAssembler::AccumulatorRegisterValue,
+                                              TrustedImm32(1),
+                                              PlatformAssembler::ScratchRegister);
+        pasm()->setAccumulatorTag(IntegerTag, PlatformAssembler::ScratchRegister);
+        return overflowed;
+    });
 
     // slow path:
     saveAccumulatorInFrame();
@@ -1310,7 +1350,7 @@ void Assembler::inc()
     checkException();
 
     // done.
-//    done.link(pasm());
+    done.link(pasm());
 }
 
 static ReturnedValue decHelper(const Value &v)
@@ -1320,7 +1360,14 @@ static ReturnedValue decHelper(const Value &v)
 
 void Assembler::dec()
 {
-//    auto done = pasm()->decFastPath();
+    auto done = pasm()->unopIntPath([this](){
+        auto overflowed = pasm()->branchSub32(PlatformAssembler::Overflow,
+                                              PlatformAssembler::AccumulatorRegisterValue,
+                                              TrustedImm32(1),
+                                              PlatformAssembler::ScratchRegister);
+        pasm()->setAccumulatorTag(IntegerTag, PlatformAssembler::ScratchRegister);
+        return overflowed;
+    });
 
     // slow path:
     saveAccumulatorInFrame();
@@ -1330,7 +1377,7 @@ void Assembler::dec()
     checkException();
 
     // done.
-//    done.link(pasm());
+    done.link(pasm());
 }
 
 void Assembler::unot()
-- 
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