Implement enough of the missing instalias support to get

aliases installed and working.  They now work when the
matched pattern and the result instruction have exactly
the same operand list.

This is now enough for us to define proper aliases for
movzx and movsx, implementing rdar://8017633 and PR7459.

Note that we do not accept instructions like:
  movzx 0(%rsp), %rsi

GAS accepts this instruction, but it doesn't make any
sense because we don't know the size of the memory
operand.  It could be 8/16/32 bits.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117901 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 6 deletions

diff --git a/utils/TableGen/CodeGenInstruction.cpp b/utils/TableGen/CodeGenInstruction.cpp
index 8a05374d8c..7428f2c88f 100644
--- a/utils/TableGen/CodeGenInstruction.cpp
+++ b/utils/TableGen/CodeGenInstruction.cpp
@@ -110,6 +110,12 @@ CGIOperandList::CGIOperandList(Record *R) : TheDef(R) {
                                       MIOperandNo, NumOps, MIOpInfo));
     MIOperandNo += NumOps;
   }
+  
+  
+  // Make sure the constraints list for each operand is large enough to hold
+  // constraint info, even if none is present.
+  for (unsigned i = 0, e = OperandList.size(); i != e; ++i)
+    OperandList[i].Constraints.resize(OperandList[i].MINumOperands);
 }
 
 
@@ -235,11 +241,6 @@ static void ParseConstraint(const std::string &CStr, CGIOperandList &Ops) {
 }
 
 static void ParseConstraints(const std::string &CStr, CGIOperandList &Ops) {
-  // Make sure the constraints list for each operand is large enough to hold
-  // constraint info, even if none is present.
-  for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-    Ops[i].Constraints.resize(Ops[i].MINumOperands);
-  
   if (CStr.empty()) return;
   
   const std::string delims(",");
@@ -390,5 +391,5 @@ FlattenAsmStringVariants(StringRef Cur, unsigned Variant) {
 CodeGenInstAlias::CodeGenInstAlias(Record *R) : TheDef(R), Operands(R) {
   AsmString = R->getValueAsString("AsmString");
 
-  
+  Result = R->getValueAsDag("ResultInst");
 }