Add debug output for rematerializable instructions.

llvm-svn: 129883

3 files changed, 10 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/InlineSpiller.cpp b/llvm/lib/CodeGen/InlineSpiller.cpp
index bcbe718bc86..0a785565f6c 100644
--- a/llvm/lib/CodeGen/InlineSpiller.cpp
+++ b/llvm/lib/CodeGen/InlineSpiller.cpp
@@ -420,8 +420,10 @@ void InlineSpiller::analyzeSiblingValues() {
       }
       if (!DefMI && !VNI->isPHIDef())
         DefMI = LIS.getInstructionFromIndex(VNI->def);
-      if (DefMI)
-        Edit->checkRematerializable(VNI, DefMI, TII, AA);
+      if (DefMI && Edit->checkRematerializable(VNI, DefMI, TII, AA)) {
+        DEBUG(dbgs() << "Value " << PrintReg(Reg) << ':' << VNI->id << '@'
+                     << VNI->def << " may remat from " << *DefMI);
+      }
     }
   }
 }
diff --git a/llvm/lib/CodeGen/LiveRangeEdit.cpp b/llvm/lib/CodeGen/LiveRangeEdit.cpp
index b1dc9019ccc..443cc2e9048 100644
--- a/llvm/lib/CodeGen/LiveRangeEdit.cpp
+++ b/llvm/lib/CodeGen/LiveRangeEdit.cpp
@@ -36,14 +36,16 @@ LiveInterval &LiveRangeEdit::createFrom(unsigned OldReg,
   return LI;
 }
 
-void LiveRangeEdit::checkRematerializable(VNInfo *VNI,
+bool LiveRangeEdit::checkRematerializable(VNInfo *VNI,
                                           const MachineInstr *DefMI,
                                           const TargetInstrInfo &tii,
                                           AliasAnalysis *aa) {
   assert(DefMI && "Missing instruction");
-  if (tii.isTriviallyReMaterializable(DefMI, aa))
-    remattable_.insert(VNI);
   scannedRemattable_ = true;
+  if (!tii.isTriviallyReMaterializable(DefMI, aa))
+    return false;
+  remattable_.insert(VNI);
+  return true;
 }
 
 void LiveRangeEdit::scanRemattable(LiveIntervals &lis,
diff --git a/llvm/lib/CodeGen/LiveRangeEdit.h b/llvm/lib/CodeGen/LiveRangeEdit.h
index 54a2c83fd6f..c008d7647db 100644
--- a/llvm/lib/CodeGen/LiveRangeEdit.h
+++ b/llvm/lib/CodeGen/LiveRangeEdit.h
@@ -137,7 +137,7 @@ public:
 
   /// checkRematerializable - Manually add VNI to the list of rematerializable
   /// values if DefMI may be rematerializable.
-  void checkRematerializable(VNInfo *VNI, const MachineInstr *DefMI,
+  bool checkRematerializable(VNInfo *VNI, const MachineInstr *DefMI,
                              const TargetInstrInfo&, AliasAnalysis*);
 
   /// Remat - Information needed to rematerialize at a specific location.