When setting a tied check if it's already tied. If it's tied to another constraint it's invalid. Fixes PR3905.

llvm-svn: 118146

1 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/Basic/TargetInfo.cpp b/clang/lib/Basic/TargetInfo.cpp
index 947cbfc3f6d..1437a4ba015 100644
--- a/clang/lib/Basic/TargetInfo.cpp
+++ b/clang/lib/Basic/TargetInfo.cpp
@@ -354,6 +354,11 @@ bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
         if (OutputConstraints[i].isReadWrite())
           return false;
 
+        // If the constraint is already tied, it must be tied to the 
+        // same operand referenced to by the number.
+        if (Info.hasTiedOperand() && Info.getTiedOperand() != i)
+          return false;
+
         // The constraint should have the same info as the respective
         // output constraint.
         Info.setTiedOperand(i, OutputConstraints[i]);
@@ -369,6 +374,11 @@ bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
       if (!resolveSymbolicName(Name, OutputConstraints, NumOutputs, Index))
         return false;
 
+      // If the constraint is already tied, it must be tied to the 
+      // same operand referenced to by the number.
+      if (Info.hasTiedOperand() && Info.getTiedOperand() != Index)
+        return false;
+
       Info.setTiedOperand(Index, OutputConstraints[Index]);
       break;
     }