Change MRegisterDesc::AliasSet, TargetInstrDescriptor::ImplicitDefs

and TargetInstrDescriptor::ImplicitUses to always point to a null
terminated array and never be null. So there is no need to check for
pointer validity when iterating over those sets. Code that looked
like:

if (const unsigned* AS = TID.ImplicitDefs) {
  for (int i = 0; AS[i]; ++i) {
    // use AS[i]
  }
}

was changed to:

for (const unsigned* AS = TID.ImplicitDefs; *AS; ++AS) {
  // use *AS
}


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8960 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 3 deletions

diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp
index 13cd353362..0ceb866965 100644
--- a/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/lib/CodeGen/PrologEpilogInserter.cpp
@@ -127,12 +127,15 @@ void PEI::saveCallerSavedRegisters(MachineFunction &Fn) {
     unsigned Reg = CSRegs[i];
     if (ModifiedRegs[Reg]) {
       RegsToSave.push_back(Reg);  // If modified register...
-    } else if (const unsigned *AliasSet = RegInfo->getAliasSet(Reg))
-      for (unsigned j = 0; AliasSet[j]; ++j)     // Check alias registers too...
-	if (ModifiedRegs[AliasSet[j]]) {
+    } else {
+      for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
+           *AliasSet; ++AliasSet) {  // Check alias registers too...
+	if (ModifiedRegs[*AliasSet]) {
 	  RegsToSave.push_back(Reg);
 	  break;
 	}
+      }
+    }
   }
 
   if (RegsToSave.empty())