[llvm-commits] [llvm] r83932 - in /llvm/trunk: include/llvm/ADT/APInt.h unittests/ADT/APIntTest.cpp
Dan Gohman
gohman at apple.com
Mon Oct 12 18:49:02 PDT 2009
Author: djg
Date: Mon Oct 12 20:49:02 2009
New Revision: 83932
URL: http://llvm.org/viewvc/llvm-project?rev=83932&view=rev
Log:
Add a ceilLogBase2 function to APInt.
Modified:
llvm/trunk/include/llvm/ADT/APInt.h
llvm/trunk/unittests/ADT/APIntTest.cpp
Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=83932&r1=83931&r2=83932&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Mon Oct 12 20:49:02 2009
@@ -1234,6 +1234,11 @@
return BitWidth - 1 - countLeadingZeros();
}
+ /// @returns the ceil log base 2 of this APInt.
+ unsigned ceilLogBase2() const {
+ return BitWidth - (*this - 1).countLeadingZeros();
+ }
+
/// @returns the log base 2 of this APInt if its an exact power of two, -1
/// otherwise
int32_t exactLogBase2() const {
Modified: llvm/trunk/unittests/ADT/APIntTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/ADT/APIntTest.cpp?rev=83932&r1=83931&r2=83932&view=diff
==============================================================================
--- llvm/trunk/unittests/ADT/APIntTest.cpp (original)
+++ llvm/trunk/unittests/ADT/APIntTest.cpp Mon Oct 12 20:49:02 2009
@@ -315,6 +315,17 @@
EXPECT_EQ(9U, APInt::getBitsNeeded("-20", 16));
}
+TEST(APIntTest, Log2) {
+ EXPECT_EQ(APInt(15, 7).logBase2(), 2);
+ EXPECT_EQ(APInt(15, 7).ceilLogBase2(), 3);
+ EXPECT_EQ(APInt(15, 7).exactLogBase2(), -1);
+ EXPECT_EQ(APInt(15, 8).logBase2(), 3);
+ EXPECT_EQ(APInt(15, 8).ceilLogBase2(), 3);
+ EXPECT_EQ(APInt(15, 8).exactLogBase2(), 3);
+ EXPECT_EQ(APInt(15, 9).logBase2(), 3);
+ EXPECT_EQ(APInt(15, 9).ceilLogBase2(), 4);
+ EXPECT_EQ(APInt(15, 9).exactLogBase2(), -1);
+}
#ifdef GTEST_HAS_DEATH_TEST
TEST(APIntTest, StringDeath) {
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