<div class="gmail_extra"><div class="gmail_quote">On Wed, Aug 29, 2012 at 3:57 PM, Benjamin Kramer <span dir="ltr"><<a href="mailto:benny.kra@googlemail.com" target="_blank" class="cremed">benny.kra@googlemail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Author: d0k<br>
Date: Wed Aug 29 17:57:00 2012<br>
New Revision: 162873<br>
<br>
URL: <a href="http://llvm.org/viewvc/llvm-project?rev=162873&view=rev" target="_blank" class="cremed">http://llvm.org/viewvc/llvm-project?rev=162873&view=rev</a><br>
Log:<br>
Replace the BUILTIN_EXPECT macro with a less horrible LLVM_LIKELY/LLVM_UNLIKELY interface.<br>
<br>
Modified:<br>
    llvm/trunk/include/llvm/Support/Compiler.h<br>
    llvm/trunk/lib/Support/raw_ostream.cpp<br>
<br>
Modified: llvm/trunk/include/llvm/Support/Compiler.h<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compiler.h?rev=162873&r1=162872&r2=162873&view=diff" target="_blank" class="cremed">http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compiler.h?rev=162873&r1=162872&r2=162873&view=diff</a><br>

==============================================================================<br>
--- llvm/trunk/include/llvm/Support/Compiler.h (original)<br>
+++ llvm/trunk/include/llvm/Support/Compiler.h Wed Aug 29 17:57:00 2012<br>
@@ -106,9 +106,11 @@<br>
 #endif<br>
<br>
 #if (__GNUC__ >= 4)<br>
-#define BUILTIN_EXPECT(EXPR, VALUE) __builtin_expect((EXPR), (VALUE))<br>
+#define LLVM_LIKELY(EXPR) __builtin_expect((EXPR), true)<br>
+#define LLVM_UNLIKELY(EXPR) __builtin_expect((EXPR), false)<br></blockquote><div><br></div><div>Do you want to cast (EXPR) to bool before handing it to __builtin_expect? The true variant will do the wrong thing for integers in some weird cases without that...</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
 #else<br>
-#define BUILTIN_EXPECT(EXPR, VALUE) (EXPR)<br>
+#define LLVM_LIKELY(EXPR) (EXPR)<br>
+#define LLVM_UNLIKELY(EXPR) (EXPR)<br>
 #endif<br>
<br>
<br>
<br>
Modified: llvm/trunk/lib/Support/raw_ostream.cpp<br>
URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=162873&r1=162872&r2=162873&view=diff" target="_blank" class="cremed">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=162873&r1=162872&r2=162873&view=diff</a><br>

==============================================================================<br>
--- llvm/trunk/lib/Support/raw_ostream.cpp (original)<br>
+++ llvm/trunk/lib/Support/raw_ostream.cpp Wed Aug 29 17:57:00 2012<br>
@@ -266,8 +266,8 @@<br>
<br>
 raw_ostream &raw_ostream::write(unsigned char C) {<br>
   // Group exceptional cases into a single branch.<br>
-  if (BUILTIN_EXPECT(OutBufCur >= OutBufEnd, false)) {<br>
-    if (BUILTIN_EXPECT(!OutBufStart, false)) {<br>
+  if (LLVM_UNLIKELY(OutBufCur >= OutBufEnd)) {<br>
+    if (LLVM_UNLIKELY(!OutBufStart)) {<br>
       if (BufferMode == Unbuffered) {<br>
         write_impl(reinterpret_cast<char*>(&C), 1);<br>
         return *this;<br>
@@ -286,8 +286,8 @@<br>
<br>
 raw_ostream &raw_ostream::write(const char *Ptr, size_t Size) {<br>
   // Group exceptional cases into a single branch.<br>
-  if (BUILTIN_EXPECT(size_t(OutBufEnd - OutBufCur) < Size, false)) {<br>
-    if (BUILTIN_EXPECT(!OutBufStart, false)) {<br>
+  if (LLVM_UNLIKELY(size_t(OutBufEnd - OutBufCur) < Size)) {<br>
+    if (LLVM_UNLIKELY(!OutBufStart)) {<br>
       if (BufferMode == Unbuffered) {<br>
         write_impl(Ptr, Size);<br>
         return *this;<br>
@@ -302,7 +302,7 @@<br>
     // If the buffer is empty at this point we have a string that is larger<br>
     // than the buffer. Directly write the chunk that is a multiple of the<br>
     // preferred buffer size and put the remainder in the buffer.<br>
-    if (BUILTIN_EXPECT(OutBufCur == OutBufStart, false)) {<br>
+    if (LLVM_UNLIKELY(OutBufCur == OutBufStart)) {<br>
       size_t BytesToWrite = Size - (Size % NumBytes);<br>
       write_impl(Ptr, BytesToWrite);<br>
       copy_to_buffer(Ptr + BytesToWrite, Size - BytesToWrite);<br>
@@ -523,7 +523,7 @@<br>
     ssize_t ret;<br>
<br>
     // Check whether we should attempt to use atomic writes.<br>
-    if (BUILTIN_EXPECT(!UseAtomicWrites, true)) {<br>
+    if (LLVM_LIKELY(!UseAtomicWrites)) {<br>
       ret = ::write(FD, Ptr, Size);<br>
     } else {<br>
       // Use ::writev() where available.<br>
<br>
<br>
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</blockquote></div><br></div>