Title: [232244] trunk/Source
- Revision
- 232244
- Author
- [email protected]
- Date
- 2018-05-28 05:26:05 -0700 (Mon, 28 May 2018)
Log Message
[WTF] Add clz32 / clz64 for MSVC
https://bugs.webkit.org/show_bug.cgi?id=186023
Reviewed by Daniel Bates.
Source/_javascript_Core:
Move clz32 and clz64 to WTF.
* runtime/MathCommon.h:
(JSC::clz32): Deleted.
(JSC::clz64): Deleted.
Source/WTF:
This patch adds efficient implementations of clz32 and clz64 for MSVC.
While MSVC has _lzcnt intrinsic, it is only valid if the CPU has lzcnt instruction.
Instead of checking cpuid here, we just use _BitScanReverse and _BitScanReverse64.
* wtf/MathExtras.h:
(WTF::clz32):
(WTF::clz64):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (232243 => 232244)
--- trunk/Source/_javascript_Core/ChangeLog 2018-05-28 10:57:19 UTC (rev 232243)
+++ trunk/Source/_javascript_Core/ChangeLog 2018-05-28 12:26:05 UTC (rev 232244)
@@ -1,3 +1,16 @@
+2018-05-27 Yusuke Suzuki <[email protected]>
+
+ [WTF] Add clz32 / clz64 for MSVC
+ https://bugs.webkit.org/show_bug.cgi?id=186023
+
+ Reviewed by Daniel Bates.
+
+ Move clz32 and clz64 to WTF.
+
+ * runtime/MathCommon.h:
+ (JSC::clz32): Deleted.
+ (JSC::clz64): Deleted.
+
2018-05-27 Caio Lima <[email protected]>
[ESNext][BigInt] Implement "+" and "-" unary operation
Modified: trunk/Source/_javascript_Core/runtime/MathCommon.h (232243 => 232244)
--- trunk/Source/_javascript_Core/runtime/MathCommon.h 2018-05-28 10:57:19 UTC (rev 232243)
+++ trunk/Source/_javascript_Core/runtime/MathCommon.h 2018-05-28 12:26:05 UTC (rev 232244)
@@ -47,44 +47,6 @@
return -9007199254740991.0;
}
-inline int clz32(uint32_t number)
-{
-#if COMPILER(GCC_OR_CLANG)
- int zeroCount = 32;
- if (number)
- zeroCount = __builtin_clz(number);
- return zeroCount;
-#else
- int zeroCount = 0;
- for (int i = 31; i >= 0; i--) {
- if (!(number >> i))
- zeroCount++;
- else
- break;
- }
- return zeroCount;
-#endif
-}
-
-inline int clz64(uint64_t number)
-{
-#if COMPILER(GCC_OR_CLANG)
- int zeroCount = 64;
- if (number)
- zeroCount = __builtin_clzll(number);
- return zeroCount;
-#else
- int zeroCount = 0;
- for (int i = 63; i >= 0; i--) {
- if (!(number >> i))
- zeroCount++;
- else
- break;
- }
- return zeroCount;
-#endif
-}
-
// This in the ToInt32 operation is defined in section 9.5 of the ECMA-262 spec.
// Note that this operation is identical to ToUInt32 other than to interpretation
// of the resulting bit-pattern (as such this method is also called to implement
Modified: trunk/Source/WTF/ChangeLog (232243 => 232244)
--- trunk/Source/WTF/ChangeLog 2018-05-28 10:57:19 UTC (rev 232243)
+++ trunk/Source/WTF/ChangeLog 2018-05-28 12:26:05 UTC (rev 232244)
@@ -1,3 +1,18 @@
+2018-05-27 Yusuke Suzuki <[email protected]>
+
+ [WTF] Add clz32 / clz64 for MSVC
+ https://bugs.webkit.org/show_bug.cgi?id=186023
+
+ Reviewed by Daniel Bates.
+
+ This patch adds efficient implementations of clz32 and clz64 for MSVC.
+ While MSVC has _lzcnt intrinsic, it is only valid if the CPU has lzcnt instruction.
+ Instead of checking cpuid here, we just use _BitScanReverse and _BitScanReverse64.
+
+ * wtf/MathExtras.h:
+ (WTF::clz32):
+ (WTF::clz64):
+
2018-05-26 Filip Pizlo <[email protected]>
testair sometimes crashes due to races in initialization of ARC4RandomNumberGenerator
Modified: trunk/Source/WTF/wtf/MathExtras.h (232243 => 232244)
--- trunk/Source/WTF/wtf/MathExtras.h 2018-05-28 10:57:19 UTC (rev 232243)
+++ trunk/Source/WTF/wtf/MathExtras.h 2018-05-28 12:26:05 UTC (rev 232244)
@@ -524,6 +524,56 @@
shuffleVector(vector, vector.size(), randomFunc);
}
+inline unsigned clz32(uint32_t number)
+{
+#if COMPILER(GCC_OR_CLANG)
+ if (number)
+ return __builtin_clz(number);
+ return 32;
+#elif COMPILER(MSVC)
+ // Visual Studio 2008 or upper have __lzcnt, but we can't detect Intel AVX at compile time.
+ // So we use bit-scan-reverse operation to calculate clz.
+ unsigned long ret = 0;
+ if (_BitScanReverse(&ret, number))
+ return 31 - ret;
+ return 32;
+#else
+ unsigned zeroCount = 0;
+ for (int i = 31; i >= 0; i--) {
+ if (!(number >> i))
+ zeroCount++;
+ else
+ break;
+ }
+ return zeroCount;
+#endif
+}
+
+inline unsigned clz64(uint64_t number)
+{
+#if COMPILER(GCC_OR_CLANG)
+ if (number)
+ return __builtin_clzll(number);
+ return 64;
+#elif COMPILER(MSVC)
+ // Visual Studio 2008 or upper have __lzcnt, but we can't detect Intel AVX at compile time.
+ // So we use bit-scan-reverse operation to calculate clz.
+ unsigned long ret = 0;
+ if (_BitScanReverse64(&ret, number))
+ return 63 - ret;
+ return 64;
+#else
+ unsigned zeroCount = 0;
+ for (int i = 63; i >= 0; i--) {
+ if (!(number >> i))
+ zeroCount++;
+ else
+ break;
+ }
+ return zeroCount;
+#endif
+}
+
} // namespace WTF
using WTF::opaque;
@@ -531,5 +581,7 @@
using WTF::preciseIndexMaskShift;
using WTF::preciseIndexMaskShiftForSize;
using WTF::shuffleVector;
+using WTF::clz32;
+using WTF::clz64;
#endif // #ifndef WTF_MathExtras_h
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