Subzero: Dump register numbers as signed quantities.

src/IceRegAlloc.cpp

Index: src/IceRegAlloc.cpp
diff --git a/src/IceRegAlloc.cpp b/src/IceRegAlloc.cpp
index e7538525c1337f91abe73b03a0846c082c515f23..ccd1a930fef5850959dc1fb7c4c32067e671ddcf 100644
--- a/src/IceRegAlloc.cpp
+++ b/src/IceRegAlloc.cpp
@@ -71,8 +71,8 @@ void dumpLiveRange(const Variable *Var, const Cfg *Func) {
     return;
   Ostream &Str = Func->getContext()->getStrDump();
   char buf[30];
-  snprintf(buf, llvm::array_lengthof(buf), "%2u",
-           unsigned(Var->getRegNumTmp()));
+  snprintf(buf, llvm::array_lengthof(buf), "%2d",

[John, 2016/04/06 16:36:14]

What about printing None instead of -1?

[Jim Stichnoth, 2016/04/06 17:04:37]

I tried that, but then I realized that the whole snprintf plumbing is to try to
make the output line up nicely in columns.  Practically all register numbers
(including -1) fit within 2 chars.

I could do something else, maybe "xx" or "--"?  What do you think?  One think I
noticed is that "R=-1" and "R= 1" are a bit hard to distinguish in the output.

+           int32_t(Var->getRegNumTmp()));
   Str << "R=" << buf << "  V=";
   Var->dump(Func);
   Str << "  Range=" << Var->getLiveRange();