From 45afcc26ffa38e6a7d9afddf497a92438dca608f Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@google.com>
Date: Tue, 2 Jul 2013 10:40:04 -0700
Subject: [PATCH] Bug 866137 - Implement range analysis for
 LoadTypedArrayElement r=jandem

---
 js/src/ion/MIR.h             |  2 ++
 js/src/ion/RangeAnalysis.cpp | 30 +++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/js/src/ion/MIR.h b/js/src/ion/MIR.h
index 2c53de252f3..d7bffd30b6b 100644
--- a/js/src/ion/MIR.h
+++ b/js/src/ion/MIR.h
@@ -4949,6 +4949,8 @@ class MLoadTypedArrayElement
     AliasSet getAliasSet() const {
         return AliasSet::Load(AliasSet::TypedArrayElement);
     }
+
+    void computeRange();
 };
 
 // Load a value from a typed array. Out-of-bounds accesses are handled using
diff --git a/js/src/ion/RangeAnalysis.cpp b/js/src/ion/RangeAnalysis.cpp
index e4527add4dd..348c28af235 100644
--- a/js/src/ion/RangeAnalysis.cpp
+++ b/js/src/ion/RangeAnalysis.cpp
@@ -769,10 +769,38 @@ MToInt32::computeRange()
     setRange(new Range(input.lower(), input.upper()));
 }
 
+static Range *GetTypedArrayRange(int type)
+{
+    switch (type) {
+      case TypedArray::TYPE_UINT8_CLAMPED:
+      case TypedArray::TYPE_UINT8:  return new Range(0, UINT8_MAX);
+      case TypedArray::TYPE_UINT16: return new Range(0, UINT16_MAX);
+      case TypedArray::TYPE_UINT32: return new Range(0, UINT32_MAX);
+
+      case TypedArray::TYPE_INT8:   return new Range(INT8_MIN, INT8_MAX);
+      case TypedArray::TYPE_INT16:  return new Range(INT16_MIN, INT16_MAX);
+      case TypedArray::TYPE_INT32:  return new Range(INT32_MIN, INT32_MAX);
+
+      case TypedArray::TYPE_FLOAT32:
+      case TypedArray::TYPE_FLOAT64:
+        break;
+    }
+
+  return NULL;
+}
+
+void
+MLoadTypedArrayElement::computeRange()
+{
+    if (Range *range = GetTypedArrayRange(arrayType()))
+        setRange(range);
+}
+
 void
 MLoadTypedArrayElementStatic::computeRange()
 {
-    setRange(new Range(this));
+    if (Range *range = GetTypedArrayRange(TypedArray::type(typedArray_)))
+        setRange(range);
 }
 
 ///////////////////////////////////////////////////////////////////////////////