Point people to ConstantExpr and ConstantFolding,

[oota-llvm.git] / include / llvm / Support / MathExtras.h

diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h
index 3955735d0b027dcda13f09e313fe7a98fbb0852f..8a89d85cd58fa019b10ee9de7ba5b895c5c338a7 100644 (file)
--- a/include/llvm/Support/MathExtras.h
+++ b/include/llvm/Support/MathExtras.h
@@ -2,8 +2,8 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
@@ -163,6 +163,14 @@ inline unsigned CountLeadingZeros_32(uint32_t Value) {
   return Count;
 }
 
+/// CountLeadingOnes_32 - this function performs the operation of
+/// counting the number of ones from the most significant bit to the first zero
+/// bit.  Ex. CountLeadingOnes_32(0xFF0FFF00) == 8.
+/// Returns 32 if the word is all ones.
+inline unsigned CountLeadingOnes_32(uint32_t Value) {
+  return CountLeadingZeros_32(~Value);
+}
+
 /// CountLeadingZeros_64 - This function performs the platform optimal form
 /// of counting the number of zeros from the most significant bit to the first 
 /// one bit (64 bit edition.)
@@ -207,6 +215,14 @@ inline unsigned CountLeadingZeros_64(uint64_t Value) {
   return Count;
 }
 
+/// CountLeadingOnes_64 - This function performs the operation
+/// of counting the number of ones from the most significant bit to the first 
+/// zero bit (64 bit edition.)
+/// Returns 64 if the word is all ones.
+inline unsigned CountLeadingOnes_64(uint64_t Value) {
+  return CountLeadingZeros_64(~Value);
+}
+
 /// CountTrailingZeros_32 - this function performs the platform optimal form of
 /// counting the number of zeros from the least significant bit to the first one
 /// bit.  Ex. CountTrailingZeros_32(0xFF00FF00) == 8.
@@ -224,6 +240,14 @@ inline unsigned CountTrailingZeros_32(uint32_t Value) {
 #endif
 }
 
+/// CountTrailingOnes_32 - this function performs the operation of
+/// counting the number of ones from the least significant bit to the first zero
+/// bit.  Ex. CountTrailingOnes_32(0x00FF00FF) == 8.
+/// Returns 32 if the word is all ones.
+inline unsigned CountTrailingOnes_32(uint32_t Value) {
+  return CountTrailingZeros_32(~Value);
+}
+
 /// CountTrailingZeros_64 - This function performs the platform optimal form
 /// of counting the number of zeros from the least significant bit to the first 
 /// one bit (64 bit edition.)
@@ -243,6 +267,14 @@ inline unsigned CountTrailingZeros_64(uint64_t Value) {
 #endif
 }
 
+/// CountTrailingOnes_64 - This function performs the operation
+/// of counting the number of ones from the least significant bit to the first 
+/// zero bit (64 bit edition.)
+/// Returns 64 if the word is all ones.
+inline unsigned CountTrailingOnes_64(uint64_t Value) {
+  return CountTrailingZeros_64(~Value);
+}
+
 /// CountPopulation_32 - this function counts the number of set bits in a value.
 /// Ex. CountPopulation(0xF000F000) = 8
 /// Returns 0 if the word is zero.
@@ -360,11 +392,23 @@ int IsInf(double d);
 
 /// MinAlign - A and B are either alignments or offsets.  Return the minimum
 /// alignment that may be assumed after adding the two together.
-static inline unsigned MinAlign(unsigned A, unsigned B) {
+static inline uint64_t MinAlign(uint64_t A, uint64_t B) {
   // The largest power of 2 that divides both A and B.
   return (A | B) & -(A | B);
 }
 
+/// NextPowerOf2 - Returns the next power of two (in 64-bits)
+/// that is strictly greater than A.  Returns zero on overflow.
+static inline uint64_t NextPowerOf2(uint64_t A) {
+  A |= (A >> 1);
+  A |= (A >> 2);
+  A |= (A >> 4);
+  A |= (A >> 8);
+  A |= (A >> 16);
+  A |= (A >> 32);
+  return A + 1;
+}
+  
 } // End llvm namespace
 
 #endif