Allow InstAlias's to use immediate matcher patterns that xform the value.

For example,

On ARM, "mov r3, #-3" is an alias for "mvn r3, #2", so we want to use a
matcher pattern that handles the bitwise negation when mapping to t2MVNi.

llvm-svn: 143233

2 files changed, 29 insertions, 5 deletions

diff --git a/llvm/utils/TableGen/AsmMatcherEmitter.cpp b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
index ba69aefac6b..01754c3f91e 100644
--- a/llvm/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/AsmMatcherEmitter.cpp
@@ -591,7 +591,8 @@ private:
 
   /// getOperandClass - Lookup or create the class for the given operand.
   ClassInfo *getOperandClass(const CGIOperandList::OperandInfo &OI,
-                             int SubOpIdx = -1);
+                             int SubOpIdx);
+  ClassInfo *getOperandClass(Record *Rec, int SubOpIdx);
 
   /// BuildRegisterClasses - Build the ClassInfo* instances for register
   /// classes.
@@ -870,7 +871,11 @@ AsmMatcherInfo::getOperandClass(const CGIOperandList::OperandInfo &OI,
   Record *Rec = OI.Rec;
   if (SubOpIdx != -1)
     Rec = dynamic_cast<DefInit*>(OI.MIOperandInfo->getArg(SubOpIdx))->getDef();
+  return getOperandClass(Rec, SubOpIdx);
+}
 
+ClassInfo *
+AsmMatcherInfo::getOperandClass(Record *Rec, int SubOpIdx) {
   if (Rec->isSubClassOf("RegisterOperand")) {
     // RegisterOperand may have an associated ParserMatchClass. If it does,
     // use it, else just fall back to the underlying register class.
@@ -1375,9 +1380,11 @@ void AsmMatcherInfo::BuildAliasOperandReference(MatchableInfo *II,
         CGA.ResultOperands[i].getName() == OperandName) {
       // It's safe to go with the first one we find, because CodeGenInstAlias
       // validates that all operands with the same name have the same record.
-      unsigned ResultIdx = CGA.ResultInstOperandIndex[i].first;
       Op.SubOpIdx = CGA.ResultInstOperandIndex[i].second;
-      Op.Class = getOperandClass(CGA.ResultInst->Operands[ResultIdx],
+      // Use the match class from the Alias definition, not the
+      // destination instruction, as we may have an immediate that's
+      // being munged by the match class.
+      Op.Class = getOperandClass(CGA.ResultOperands[i].getRecord(),
                                  Op.SubOpIdx);
       Op.SrcOpName = OperandName;
       return;
diff --git a/llvm/utils/TableGen/CodeGenInstruction.cpp b/llvm/utils/TableGen/CodeGenInstruction.cpp
index 9822de819db..d6515cade27 100644
--- a/llvm/utils/TableGen/CodeGenInstruction.cpp
+++ b/llvm/utils/TableGen/CodeGenInstruction.cpp
@@ -428,8 +428,11 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
   if (ADI && ADI->getDef()->isSubClassOf("RegisterClass")) {
     if (!InstOpRec->isSubClassOf("RegisterClass"))
       return false;
-    return T.getRegisterClass(InstOpRec)
-              .hasSubClass(&T.getRegisterClass(ADI->getDef()));
+    if (!T.getRegisterClass(InstOpRec)
+              .hasSubClass(&T.getRegisterClass(ADI->getDef())))
+      return false;
+    ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
+    return true;
   }
 
   // Handle explicit registers.
@@ -473,6 +476,7 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
     return true;
   }
 
+  // Literal integers.
   if (IntInit *II = dynamic_cast<IntInit*>(Arg)) {
     if (hasSubOps || !InstOpRec->isSubClassOf("Operand"))
       return false;
@@ -484,6 +488,19 @@ bool CodeGenInstAlias::tryAliasOpMatch(DagInit *Result, unsigned AliasOpNo,
     return true;
   }
 
+  // If both are Operands with the same MVT, allow the conversion. It's
+  // up to the user to make sure the values are appropriate, just like
+  // for isel Pat's.
+  if (InstOpRec->isSubClassOf("Operand") &&
+      ADI->getDef()->isSubClassOf("Operand")) {
+    // FIXME: What other attributes should we check here? Identical
+    // MIOperandInfo perhaps?
+    if (InstOpRec->getValueInit("Type") != ADI->getDef()->getValueInit("Type"))
+      return false;
+    ResOp = ResultOperand(Result->getArgName(AliasOpNo), ADI->getDef());
+    return true;
+  }
+
   return false;
 }