[llvm-commits] [llvm] r79375 - /llvm/trunk/lib/Support/raw_ostream.cpp
Daniel Dunbar
daniel at zuster.org
Tue Aug 18 15:24:01 PDT 2009
Author: ddunbar
Date: Tue Aug 18 17:24:00 2009
New Revision: 79375
URL: http://llvm.org/viewvc/llvm-project?rev=79375&view=rev
Log:
Speed up raw_ostream::<<(unsigned long long) for 32-bit systems by doing most
div/mods in 32-bits.
Modified:
llvm/trunk/lib/Support/raw_ostream.cpp
Modified: llvm/trunk/lib/Support/raw_ostream.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=79375&r1=79374&r2=79375&view=diff
==============================================================================
--- llvm/trunk/lib/Support/raw_ostream.cpp (original)
+++ llvm/trunk/lib/Support/raw_ostream.cpp Tue Aug 18 17:24:00 2009
@@ -125,19 +125,24 @@
}
raw_ostream &raw_ostream::operator<<(unsigned long long N) {
- // Output using 32-bit div/mod when possible.
+ // Handle simple case when value fits in long already.
if (N == static_cast<unsigned long>(N))
return this->operator<<(static_cast<unsigned long>(N));
- char NumberBuffer[20];
- char *EndPtr = NumberBuffer+sizeof(NumberBuffer);
- char *CurPtr = EndPtr;
-
- while (N) {
- *--CurPtr = '0' + char(N % 10);
- N /= 10;
- }
- return write(CurPtr, EndPtr-CurPtr);
+ // Otherwise divide into at two or three 10**9 chunks and write out using
+ // long div/mod, this is substantially faster on a 32-bit system.
+ unsigned long Top = 0, Mid = 0, Bot = N % 1000000000;
+ N /= 1000000000;
+ if (N > 1000000000) {
+ Mid = N % 1000000000;
+ Top = N / 1000000000;
+ } else
+ Mid = N;
+
+ if (Top)
+ this->operator<<(static_cast<unsigned long>(Top));
+ this->operator<<(static_cast<unsigned long>(Mid));
+ return this->operator<<(static_cast<unsigned long>(Bot));
}
raw_ostream &raw_ostream::operator<<(long long N) {
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