Changeset 184369 in webkit

Timestamp:

May 14, 2015, 9:36:27 PM (10 years ago)

Author:

mitz@apple.com

Message:

Reverted r177753, now that <rdar://problem/19347133> is fixed.

Rubber-stamped by Benjamin Poulain.

• wtf/SaturatedArithmetic.h:

(signedAddOverflows):
(signedSubtractOverflows):

Location:

trunk/Source/WTF

Files:

• ChangeLog (modified) (1 diff)
• wtf/SaturatedArithmetic.h (modified) (4 diffs)

trunk/Source/WTF/ChangeLog

@@ +1 @@
+2015-05-14  Dan Bernstein  <mitz@apple.com>
+
+        Reverted r177753, now that <rdar://problem/19347133> is fixed.
+
+        Rubber-stamped by Benjamin Poulain.
+
+        * wtf/SaturatedArithmetic.h:
+        (signedAddOverflows):
+        (signedSubtractOverflows):
+
 2015-05-14  Myles C. Maxfield  <mmaxfield@apple.com>
 

trunk/Source/WTF/wtf/SaturatedArithmetic.h

@@ -40 +40 @@
 inline bool signedAddOverflows(int32_t a, int32_t b, int32_t& result)
 {
+#if COMPILER_HAS_CLANG_BUILTIN(__builtin_sadd_overflow)
+    return __builtin_sadd_overflow(a, b, &result);
+#else
     uint32_t ua = a;
     uint32_t ub = b;
@@ -48 +51 @@
     // bit of the result and one of the values differ it did overflow.
     return !((ua ^ ub) >> 31) && (uresult ^ ua) >> 31;
+#endif
 }
 
@@ -68 +72 @@
 inline bool signedSubtractOverflows(int32_t a, int32_t b, int32_t& result)
 {
+#if COMPILER_HAS_CLANG_BUILTIN(__builtin_ssub_overflow)
+    return __builtin_ssub_overflow(a, b, &result);
+#else
     uint32_t ua = a;
     uint32_t ub = b;
@@ -76 +83 @@
     // signed bit of the result and the first value differ it did overflow.
     return (ua ^ ub) >> 31 && (uresult ^ ua) >> 31;
+#endif
 }