Bug 915846 - IonMonkey: Rename isInt32() to hasInt32Bounds() and introduce a new isInt32() which actually checks for an int32 range. r=nbp

js/src/jit/MIR.cpp

@@ -1246,7 +1246,7 @@ MBinaryArithInstruction::trySpecializeFloat32()
 bool
 MAbs::fallible() const
 {
-    return !implicitTruncate_ && (!range() || !range()->isInt32());
+    return !implicitTruncate_ && (!range() || !range()->hasInt32Bounds());
 }
 
 MDefinition *
@@ -1353,7 +1353,7 @@ MAdd::fallible()
     // either the truncation analysis shows that there are non-truncated uses.
     if (isTruncated())
         return false;
-    if (range() && range()->isInt32())
+    if (range() && range()->hasInt32Bounds())
         return false;
     return true;
 }
@@ -1364,7 +1364,7 @@ MSub::fallible()
     // see comment in MAdd::fallible()
     if (isTruncated())
         return false;
-    if (range() && range()->isInt32())
+    if (range() && range()->hasInt32Bounds())
         return false;
     return true;
 }
@@ -1432,7 +1432,7 @@ MMul::canOverflow()
 {
     if (isTruncated())
         return false;
-    return !range() || !range()->isInt32();
+    return !range() || !range()->hasInt32Bounds();
 }
 
 bool
@@ -1440,7 +1440,7 @@ MUrsh::canOverflow()
 {
     if (!canOverflow_)
         return false;
-    return !range() || !range()->isInt32();
+    return !range() || !range()->hasInt32Bounds();
 }
 
 static inline bool

js/src/jit/RangeAnalysis.cpp

@@ -693,7 +693,7 @@ Range *
 Range::min(const Range *lhs, const Range *rhs)
 {
     // If either operand is NaN, the result is NaN.
-    if (!lhs->isInt32() || !rhs->isInt32())
+    if (!lhs->hasInt32Bounds() || !rhs->hasInt32Bounds())
         return new Range();
 
     return new Range(Min(lhs->lower(), rhs->lower()),
@@ -706,7 +706,7 @@ Range *
 Range::max(const Range *lhs, const Range *rhs)
 {
     // If either operand is NaN, the result is NaN.
-    if (!lhs->isInt32() || !rhs->isInt32())
+    if (!lhs->hasInt32Bounds() || !rhs->hasInt32Bounds())
         return new Range();
 
     return new Range(Max(lhs->lower(), rhs->lower()),
@@ -1056,7 +1056,7 @@ MMod::computeRange()
 
     // If either operand is a NaN, the result is NaN. This also conservatively
     // handles Infinity cases.
-    if (!lhs.isInt32() || !rhs.isInt32())
+    if (!lhs.hasInt32Bounds() || !rhs.hasInt32Bounds())
         return;
 
     // If RHS can be zero, the result can be NaN.
@@ -1737,8 +1737,10 @@ Range::clampToInt32()
 void
 Range::wrapAroundToInt32()
 {
-    if (!isInt32())
+    if (!hasInt32Bounds())
         set(JSVAL_INT_MIN, JSVAL_INT_MAX);
+    else if (canHaveFractionalPart())
+        set(lower(), upper(), false, exponent());
 }
 
 void
@@ -1835,13 +1837,22 @@ MDiv::truncate()
     // Remember analysis, needed to remove negative zero checks.
     setTruncated(true);
 
-    // Divisions where the lhs and rhs are unsigned and the result is
-    // truncated can be lowered more efficiently.
-    if (specialization() == MIRType_Int32 && tryUseUnsignedOperands()) {
-        unsigned_ = true;
+    if (type() == MIRType_Double || type() == MIRType_Int32) {
+        specialization_ = MIRType_Int32;
+        setResultType(MIRType_Int32);
+        if (range())
+            range()->wrapAroundToInt32();
+
+        // Divisions where the lhs and rhs are unsigned and the result is
+        // truncated can be lowered more efficiently.
+        if (tryUseUnsignedOperands())
+            unsigned_ = true;
+
         return true;
     }
 
+    JS_ASSERT(specialization() != MIRType_Int32); // fixme
+
     // No modifications.
     return false;
 }

js/src/jit/RangeAnalysis.h

@@ -259,11 +259,20 @@ class Range : public TempObject {
         return hasInt32UpperBound_;
     }
 
-    bool isInt32() const {
+    // Test whether the value is known to be within [INT32_MIN,INT32_MAX].
+    // Note that this does not necessarily mean the value is an integer.
+    bool hasInt32Bounds() const {
         return hasInt32LowerBound() && hasInt32UpperBound();
     }
+
+    // Test whether the value is known to be representable as an int32.
+    bool isInt32() const {
+        return hasInt32Bounds() && !canHaveFractionalPart();
+    }
+
+    // Test whether the given value is known to be either 0 or 1.
     bool isBoolean() const {
-        return lower() >= 0 && upper() <= 1;
+        return lower() >= 0 && upper() <= 1 && !canHaveFractionalPart();
     }
 
     bool hasRoundingErrors() const {
@@ -376,7 +385,7 @@ class Range : public TempObject {
     //     exponent of JSVAL_INT_MIN == 32
     //     exponent of JSVAL_INT_MAX == 31
     void rectifyExponent() {
-        if (!isInt32()) {
+        if (!hasInt32Bounds()) {
             JS_ASSERT(max_exponent_ >= MaxInt32Exponent);
             return;
         }