TableGen/ISel: Allow PatFrag predicate code to access captured operands

Summary:
This simplifies writing predicates for pattern fragments that are
automatically re-associated or commuted.

For example, a followup patch adds patterns for fragments of the form
(add (shl $x, $y), $z) to the AMDGPU backend. Such patterns are
automatically commuted to (add $z, (shl $x, $y)), which makes it basically
impossible to refer to $x, $y, and $z generically in the PredicateCode.

With this change, the PredicateCode can refer to $x, $y, and $z simply
as `Operands[i]`.

Test confirmed that there are no changes to any of the generated files
when building all (non-experimental) targets.

Change-Id: I61c00ace7eed42c1d4edc4c5351174b56b77a79c

Reviewers: arsenm, rampitec, RKSimon, craig.topper, hfinkel, uweigand

Subscribers: wdng, tpr, llvm-commits

Differential Revision: https://reviews.llvm.org/D51994

llvm-svn: 347992

1 files changed, 9 insertions, 4 deletions

diff --git a/llvm/utils/TableGen/GlobalISelEmitter.cpp b/llvm/utils/TableGen/GlobalISelEmitter.cpp
index ad0ee3dfbc4..997ceb12bec 100644
--- a/llvm/utils/TableGen/GlobalISelEmitter.cpp
+++ b/llvm/utils/TableGen/GlobalISelEmitter.cpp
@@ -200,7 +200,8 @@ static Optional<LLTCodeGen> MVTToLLT(MVT::SimpleValueType SVT) {
 static std::string explainPredicates(const TreePatternNode *N) {
   std::string Explanation = "";
   StringRef Separator = "";
-  for (const auto &P : N->getPredicateFns()) {
+  for (const TreePredicateCall &Call : N->getPredicateCalls()) {
+    const TreePredicateFn &P = Call.Fn;
     Explanation +=
         (Separator + P.getOrigPatFragRecord()->getRecord()->getName()).str();
     Separator = ", ";
@@ -284,7 +285,9 @@ static Error isTrivialOperatorNode(const TreePatternNode *N) {
   std::string Separator = "";
 
   bool HasUnsupportedPredicate = false;
-  for (const auto &Predicate : N->getPredicateFns()) {
+  for (const TreePredicateCall &Call : N->getPredicateCalls()) {
+    const TreePredicateFn &Predicate = Call.Fn;
+
     if (Predicate.isAlwaysTrue())
       continue;
 
@@ -3117,7 +3120,8 @@ Record *GlobalISelEmitter::findNodeEquiv(Record *N) const {
 
 const CodeGenInstruction *
 GlobalISelEmitter::getEquivNode(Record &Equiv, const TreePatternNode *N) const {
-  for (const auto &Predicate : N->getPredicateFns()) {
+  for (const TreePredicateCall &Call : N->getPredicateCalls()) {
+    const TreePredicateFn &Predicate = Call.Fn;
     if (!Equiv.isValueUnset("IfSignExtend") && Predicate.isLoad() &&
         Predicate.isSignExtLoad())
       return &Target.getInstruction(Equiv.getValueAsDef("IfSignExtend"));
@@ -3186,7 +3190,8 @@ Expected<InstructionMatcher &> GlobalISelEmitter::createAndImportSelDAGMatcher(
                           " for result of Src pattern operator");
   }
 
-  for (const auto &Predicate : Src->getPredicateFns()) {
+  for (const TreePredicateCall &Call : Src->getPredicateCalls()) {
+    const TreePredicateFn &Predicate = Call.Fn;
     if (Predicate.isAlwaysTrue())
       continue;