Subzero: Fix/improve -asm-verbose output.

Fixes a bug where a num-uses counter wasn't being updated because of C operator && semantics. The code was something like "if (A && --B) ..." but we want --B to happen even when A is false. Sorts the LiveIn and LiveOut lists by regnum so that the lists always display the set of registers in a consistent/familiar order. BUG= none R=jvoung@chromium.org Review URL: https://codereview.chromium.org/1152813003

Subzero: Fix/improve -asm-verbose output.
9a05aea8 · Jim Stichnoth · 55500dbc · 9a05aea8
Commit 9a05aea8 authored May 26, 2015 by Jim Stichnoth
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Showing with 24 additions and 12 deletions

IceCfgNode.cpp src/IceCfgNode.cpp +24 -12

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--- a/src/IceCfgNode.cpp
+++ b/src/IceCfgNode.cpp
@@ -794,20 +794,30 @@ void emitRegisterUsage(Ostream &Str, const Cfg *Func, const CfgNode *Node,
    Str << "\t\t\t\t# LiveOut=";
  }
  if (!Live->empty()) {
-    bool First = true;
+    std::vector<Variable *> LiveRegs;
    for (SizeT i = 0; i < Live->size(); ++i) {
      if ((*Live)[i]) {
        Variable *Var = Liveness->getVariable(i, Node);
        if (Var->hasReg()) {
          if (IsLiveIn)
            ++LiveRegCount[Var->getRegNum()];
-          if (!First)
-            Str << ",";
-          First = false;
-          Var->emit(Func);
+          LiveRegs.push_back(Var);
        }
      }
    }
+    // Sort the variables by regnum so they are always printed in a
+    // familiar order.
+    std::sort(LiveRegs.begin(), LiveRegs.end(),
+              [](const Variable *V1, const Variable *V2) {
+      return V1->getRegNum() < V2->getRegNum();
+    });
+    bool First = true;
+    for (Variable *Var : LiveRegs) {
+      if (!First)
+        Str << ",";
+      First = false;
+      Var->emit(Func);
+    }
  }
  Str << "\n";
 }
@@ -825,8 +835,14 @@ void emitLiveRangesEnded(Ostream &Str, const Cfg *Func, const Inst *Instr,
    SizeT NumVars = Src->getNumVars();
    for (SizeT J = 0; J < NumVars; ++J) {
      const Variable *Var = Src->getVar(J);
-      if (Instr->isLastUse(Var) &&
-          (!Var->hasReg() || --LiveRegCount[Var->getRegNum()] == 0)) {
+      bool ShouldEmit = Instr->isLastUse(Var);
+      if (Var->hasReg()) {
+        // Don't report end of live range until the live count reaches 0.
+        SizeT NewCount = --LiveRegCount[Var->getRegNum()];
+        if (NewCount)
+          ShouldEmit = false;
+      }
+      if (ShouldEmit) {
        if (First)
          Str << " \t# END=";
        else
@@ -884,12 +900,8 @@ void CfgNode::emit(Cfg *Func) const {
  for (const Inst &I : Insts) {
    if (I.isDeleted())
      continue;
-    if (I.isRedundantAssign()) {
-      Variable *Dest = I.getDest();
-      if (DecorateAsm && Dest->hasReg() && !I.isLastUse(I.getSrc(0)))
-        ++LiveRegCount[Dest->getRegNum()];
+    if (I.isRedundantAssign())
      continue;
-    }
    I.emit(Func);
    if (DecorateAsm)
      emitLiveRangesEnded(Str, Func, &I, LiveRegCount);