[llvm] aefaf16 - [TableGen] Fix both sides of '&&' are same

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2021-10-12T09:19:20-07:00
New Revision: aefaf167588b38768b15c57f0f0bfccfb87a399f

URL: https://github.com/llvm/llvm-project/commit/aefaf167588b38768b15c57f0f0bfccfb87a399f
DIFF: https://github.com/llvm/llvm-project/commit/aefaf167588b38768b15c57f0f0bfccfb87a399f.diff

LOG: [TableGen] Fix both sides of '&&' are same

The operand of the second any_of in EnforceSmallerThan should be
B not S like the FP code in the if below.

Unfortunately, fixing that causes an infinite loop in the build
of RISCV. So I've added a workaround for that as well.

Fixes PR44768.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D111502

Added: 
    

Modified: 
    llvm/utils/TableGen/CodeGenDAGPatterns.cpp
    llvm/utils/TableGen/CodeGenDAGPatterns.h

Removed: 
    


################################################################################
diff  --git a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
index ebb4a31d86f4f..2d0694dbc2e9b 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -451,13 +451,16 @@ static Iter max_if(Iter B, Iter E, Pred P, Less L) {
 }
 
 /// Make sure that for each type in Small, there exists a larger type in Big.
-bool TypeInfer::EnforceSmallerThan(TypeSetByHwMode &Small,
-                                   TypeSetByHwMode &Big) {
+bool TypeInfer::EnforceSmallerThan(TypeSetByHwMode &Small, TypeSetByHwMode &Big,
+                                   bool SmallIsVT) {
   ValidateOnExit _1(Small, *this), _2(Big, *this);
   if (TP.hasError())
     return false;
   bool Changed = false;
 
+  assert((!SmallIsVT || !Small.empty()) &&
+         "Small should not be empty for SDTCisVTSmallerThanOp");
+
   if (Small.empty())
     Changed |= EnforceAny(Small);
   if (Big.empty())
@@ -476,7 +479,9 @@ bool TypeInfer::EnforceSmallerThan(TypeSetByHwMode &Small,
     TypeSetByHwMode::SetType &S = Small.get(M);
     TypeSetByHwMode::SetType &B = Big.get(M);
 
-    if (any_of(S, isIntegerOrPtr) && any_of(S, isIntegerOrPtr)) {
+    assert((!SmallIsVT || !S.empty()) && "Expected non-empty type");
+
+    if (any_of(S, isIntegerOrPtr) && any_of(B, isIntegerOrPtr)) {
       auto NotInt = [](MVT VT) { return !isIntegerOrPtr(VT); };
       Changed |= berase_if(S, NotInt);
       Changed |= berase_if(B, NotInt);
@@ -484,6 +489,11 @@ bool TypeInfer::EnforceSmallerThan(TypeSetByHwMode &Small,
       auto NotFP = [](MVT VT) { return !isFloatingPoint(VT); };
       Changed |= berase_if(S, NotFP);
       Changed |= berase_if(B, NotFP);
+    } else if (SmallIsVT && B.empty()) {
+      // B is empty and since S is a specific VT, it will never be empty. Don't
+      // report this as a change, just clear S and continue. This prevents an
+      // infinite loop.
+      S.clear();
     } else if (S.empty() || B.empty()) {
       Changed = !S.empty() || !B.empty();
       S.clear();
@@ -1637,7 +1647,8 @@ bool SDTypeConstraint::ApplyTypeConstraint(TreePatternNode *N,
       getOperandNum(x.SDTCisVTSmallerThanOp_Info.OtherOperandNum, N, NodeInfo,
                     OResNo);
 
-    return TI.EnforceSmallerThan(TypeListTmp, OtherNode->getExtType(OResNo));
+    return TI.EnforceSmallerThan(TypeListTmp, OtherNode->getExtType(OResNo),
+                                 /*SmallIsVT*/ true);
   }
   case SDTCisOpSmallerThanOp: {
     unsigned BResNo = 0;

diff  --git a/llvm/utils/TableGen/CodeGenDAGPatterns.h b/llvm/utils/TableGen/CodeGenDAGPatterns.h
index a69f1e2e30305..39d81230a4f2d 100644
--- a/llvm/utils/TableGen/CodeGenDAGPatterns.h
+++ b/llvm/utils/TableGen/CodeGenDAGPatterns.h
@@ -298,8 +298,11 @@ struct TypeInfer {
   /// unchanged.
   bool EnforceAny(TypeSetByHwMode &Out);
   /// Make sure that for each type in \p Small, there exists a larger type
-  /// in \p Big.
-  bool EnforceSmallerThan(TypeSetByHwMode &Small, TypeSetByHwMode &Big);
+  /// in \p Big. \p SmallIsVT indicates that this is being called for
+  /// SDTCisVTSmallerThanOp. In that case the TypeSetByHwMode is re-created for
+  /// each call and needs special consideration in how we detect changes.
+  bool EnforceSmallerThan(TypeSetByHwMode &Small, TypeSetByHwMode &Big,
+                          bool SmallIsVT = false);
   /// 1. Ensure that for each type T in \p Vec, T is a vector type, and that
   ///    for each type U in \p Elem, U is a scalar type.
   /// 2. Ensure that for each (scalar) type U in \p Elem, there exists a