[llvm-commits] CVS: llvm/include/llvm/Support/MathExtras.h
Chris Lattner
lattner at cs.uiuc.edu
Tue Aug 2 13:21:45 PDT 2005
Changes in directory llvm/include/llvm/Support:
MathExtras.h updated: 1.19 -> 1.20
---
Log message:
Fix the non-gcc 4.0 paths for countleadingzeros
Patch fixed by Jim Laskey
---
Diffs of the changes: (+35 -29)
MathExtras.h | 64 ++++++++++++++++++++++++++++++++---------------------------
1 files changed, 35 insertions(+), 29 deletions(-)
Index: llvm/include/llvm/Support/MathExtras.h
diff -u llvm/include/llvm/Support/MathExtras.h:1.19 llvm/include/llvm/Support/MathExtras.h:1.20
--- llvm/include/llvm/Support/MathExtras.h:1.19 Tue Aug 2 15:06:18 2005
+++ llvm/include/llvm/Support/MathExtras.h Tue Aug 2 15:21:33 2005
@@ -72,36 +72,41 @@
return Value && !(Value & (Value - 1));
}
-// isPowerOf2_64 - This function returns true if the argument is a power of two > 0
-// (64 bit edition.)
+// isPowerOf2_64 - This function returns true if the argument is a power of two
+// > 0 (64 bit edition.)
inline bool isPowerOf2_64(uint64_t Value) {
return Value && !(Value & (Value - 1LL));
}
+// CountLeadingZeros_32 - this function performs the platform optimal form of
+// counting the number of zeros from the most significant bit to the first one
+// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8.
+// Returns 32 if the word is zero.
// CountLeadingZeros_32 - this function performs the platform optimal form
-// of counting the number of zeros from the most significant bit to the first one bit.
-// Ex. CountLeadingZeros_32(0x00F000FF) == 8.
+// of counting the number of zeros from the most significant bit to the first
+// one bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8.
// Returns 32 if the word is zero.
inline unsigned CountLeadingZeros_32(unsigned Value) {
unsigned Count; // result
- #if __GNUC__ >= 4
- // PowerPC is defined for __builtin_clz(0)
- #if !defined(__ppc__) && !defined(__ppc64__)
- if (!Value) return 32;
- #endif
- Count = __builtin_clz(Value);
- #else
- if (!Value) return 32;
- Count = 0;
- // bisecton method for count leading zeros
- for (unsigned Shift = 32 >> 1; Shift; Shift >>= 1) {
- unsigned Tmp = Value >> Shift;
- if (Tmp) {
- Count |= Shift;
- Value = Tmp;
- }
+#if __GNUC__ >= 4
+ // PowerPC is defined for __builtin_clz(0)
+#if !defined(__ppc__) && !defined(__ppc64__)
+ if (!Value) return 32;
+#endif
+ Count = __builtin_clz(Value);
+#else
+ if (!Value) return 32;
+ Count = 0;
+ // bisecton method for count leading zeros
+ for (unsigned Shift = 32 >> 1; Shift; Shift >>= 1) {
+ unsigned Tmp = Value >> Shift;
+ if (Tmp) {
+ Value = Tmp;
+ } else {
+ Count |= Shift;
}
- #endif
+ }
+#endif
return Count;
}
@@ -111,13 +116,13 @@
// Returns 64 if the word is zero.
inline unsigned CountLeadingZeros_64(uint64_t Value) {
unsigned Count; // result
- #if __GNUC__ >= 4
- // PowerPC is defined for __builtin_clzll(0)
- #if !defined(__ppc__) && !defined(__ppc64__)
- if (!Value) return 64;
- #endif
- Count = __builtin_clzll(Value);
- #else
+#if __GNUC__ >= 4
+ // PowerPC is defined for __builtin_clzll(0)
+#if defined(__ppc__) || defined(__ppc64__)
+ if (!Value) return 64;
+#endif
+ Count = __builtin_clzll(Value);
+#else
if (sizeof(long) == sizeof(int64_t)) {
if (!Value) return 64;
Count = 0;
@@ -125,8 +130,9 @@
for (uint64_t Shift = 64 >> 1; Shift; Shift >>= 1) {
uint64_t Tmp = Value >> Shift;
if (Tmp) {
- Count |= Shift;
Value = Tmp;
+ } else {
+ Count |= Shift;
}
}
} else {
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