Revert of Some inline ARM assembly for saturated arithmetic, a small speed-up for

Source/wtf/SaturatedArithmetic.h

Index: Source/wtf/SaturatedArithmetic.h
diff --git a/Source/wtf/SaturatedArithmetic.h b/Source/wtf/SaturatedArithmetic.h
index ff4ecb3619ec9c15f0def09274a2eaa29134dc21..981276f7c484fa779d5a30869670081984e0bfd8 100644
--- a/Source/wtf/SaturatedArithmetic.h
+++ b/Source/wtf/SaturatedArithmetic.h
@@ -31,17 +31,8 @@
 #ifndef SaturatedArithmetic_h
 #define SaturatedArithmetic_h
 
-#include "wtf/CPU.h"
 #include <limits>
 #include <stdint.h>
-
-#if CPU(ARM) && COMPILER(GCC)
-
-// If we're building ARM on GCC we replace the C++ versions with some
-// native ARM assembly for speed.
-#include "wtf/asm/SaturatedArithmeticARM.h"
-
-#else
 
 ALWAYS_INLINE int32_t saturatedAddition(int32_t a, int32_t b)
 {
@@ -49,11 +40,10 @@
     uint32_t ub = b;
     uint32_t result = ua + ub;
 
-    // Can only overflow if the signed bit of the two values match. If the
-    // signed bit of the result and one of the values differ it overflowed.
-
-    if (~(ua ^ ub) & (result ^ ua) & (1 << 31))
-        return std::numeric_limits<int>::max() + (ua >> 31);
+    // Can only overflow if the signed bit of the two values match. If the signed
+    // bit of the result and one of the values differ it did overflow.
+    if (!((ua ^ ub) >> 31) & (result ^ ua) >> 31)
+        result = std::numeric_limits<int>::max() + (ua >> 31);
 
     return result;
 }
@@ -64,56 +54,12 @@
     uint32_t ub = b;
     uint32_t result = ua - ub;
 
-    // Can only overflow if the signed bit of the two input values differ. If
-    // the signed bit of the result and the first value differ it overflowed.
-
-    if ((ua ^ ub) & (result ^ ua) & (1 << 31))
-        return std::numeric_limits<int>::max() + (ua >> 31);
+    // Can only overflow if the signed bit of the two values do not match. If the
+    // signed bit of the result and the first value differ it did overflow.
+    if ((ua ^ ub) >> 31 & (result ^ ua) >> 31)
+        result = std::numeric_limits<int>::max() + (ua >> 31);
 
     return result;
 }
 
-inline int getMaxSaturatedSetResultForTesting(int FractionalShift)
-{
-    // For C version the set function maxes out to max int, this differs from
-    // the ARM asm version, see SaturatedArithmetiARM.h for the equivalent asm
-    // version.
-    return std::numeric_limits<int>::max();
-}
-
-inline int getMinSaturatedSetResultForTesting(int FractionalShift)
-{
-    return std::numeric_limits<int>::min();
-}
-
-ALWAYS_INLINE int saturatedSet(int value, int FractionalShift)
-{
-    const int intMaxForLayoutUnit =
-        std::numeric_limits<int>::max() >> FractionalShift;
-
-    const int intMinForLayoutUnit =
-        std::numeric_limits<int>::min() >> FractionalShift;
-
-    if (value > intMaxForLayoutUnit)
-        return std::numeric_limits<int>::max();
-
-    if (value < intMinForLayoutUnit)
-        return std::numeric_limits<int>::min();
-
-    return value << FractionalShift;
-}
-
-
-ALWAYS_INLINE int saturatedSet(unsigned value, int FractionalShift)
-{
-    const unsigned intMaxForLayoutUnit =
-        std::numeric_limits<int>::max() >> FractionalShift;
-
-    if (value >= intMaxForLayoutUnit)
-        return std::numeric_limits<int>::max();
-
-    return value << FractionalShift;
-}
-
-#endif // CPU(ARM) && COMPILER(GCC)
 #endif // SaturatedArithmetic_h