From 579d21b5031763d5a808130d7397a1403cbf4972 Mon Sep 17 00:00:00 2001
From: Will Dietz <will.dietz@sifive.com>
Date: Thu, 9 Mar 2023 10:18:12 -0600
Subject: [PATCH] Revert "[FIRRTL] Canonicalizers: simplify resolve-of-send and
 hoist ref.sub out of ref.send. (#4764)"

This reverts commit 3ddf879a1ec339735174d735e0414865278c990e.

Neither of these are safe if the argument to ref.send is not passive.
Revisit in the future.
---
 .../Dialect/FIRRTL/FIRRTLCanonicalization.td  | 32 --------------
 .../circt/Dialect/FIRRTL/FIRRTLExpressions.td |  2 -
 lib/Dialect/FIRRTL/FIRRTLFolds.cpp            | 15 -------
 test/Dialect/FIRRTL/canonicalization.mlir     | 42 -------------------
 4 files changed, 91 deletions(-)

diff --git a/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td b/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td
index cbfe952de504..5294f3903eda 100644
--- a/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td
+++ b/include/circt/Dialect/FIRRTL/FIRRTLCanonicalization.td
@@ -56,19 +56,6 @@ def UIntTypes : Constraint<CPred<"$0.isa<UIntType>()">>;
 // Constraint that enforces types mismatches
 def mismatchTypes : Constraint<CPred<"$0.getType() != $1.getType()">>;
 
-// Constraint that argument is ref-of-vector type.
-def IsRefVectorType : Constraint<CPred<[{
-  $0.getType().isa<RefType>() &&
-  $0.getType().cast<RefType>().getType().isa<FVectorType>()
-}]>>;
-
-// Constraint that argument is ref-of-bundle type.
-def IsRefBundleType : Constraint<CPred<[{
-  $0.getType().isa<RefType>() &&
-  $0.getType().cast<RefType>().getType().isa<BundleType>()
-}]>>;
-
-
 // Constraint that enforces types of known width
 def KnownWidth : Constraint<CPred<[{
   $0.getType().isa<FIRRTLBaseType>() &&
@@ -363,23 +350,4 @@ def RegResetWithOneReset : Pat<
   (DropWrite $reg, (NodeOp $resetVal, $name, $nameKind, $annotations, $inner_sym)),
   [(OneConstantOp $reset)]>;
 
-// refresolve(refsend(x)) -> x
-def RefResolveOfSend : Pat<
-  (RefResolveOp (RefSendOp $orig)),
-  (replaceWithValue $orig) >;
-
-// Hoist ref.sub through send, vector variant.
-// refsub(refsend(orig), idx) -> refsend(subindex(orig, idx))
-def RefSubOfSendVector : Pat<
-  (RefSubOp (RefSendOp:$send $orig), $idx),
-  (RefSendOp (SubindexOp $orig, $idx)),
-  [(IsRefVectorType $send)] >;
-
-// Hoist ref.sub through send, bundle variant.
-// refsub(refsend(orig), idx) -> refsend(subfield(orig, idx))
-def RefSubOfSendBundle : Pat<
-  (RefSubOp (RefSendOp:$send $orig), $idx),
-  (RefSendOp (SubfieldOp $orig, $idx)),
-  [(IsRefBundleType $send)] >;
-
 #endif // CIRCT_DIALECT_FIRRTL_FIRRTLCANONICALIZATION_TD
diff --git a/include/circt/Dialect/FIRRTL/FIRRTLExpressions.td b/include/circt/Dialect/FIRRTL/FIRRTLExpressions.td
index a62b310fe821..291e7e0d0c15 100644
--- a/include/circt/Dialect/FIRRTL/FIRRTLExpressions.td
+++ b/include/circt/Dialect/FIRRTL/FIRRTLExpressions.td
@@ -807,7 +807,6 @@ def RefResolveOp: FIRRTLExprOp<"ref.resolve",
   let results = (outs FIRRTLBaseType:$result);
 
   let assemblyFormat = "$ref attr-dict `:` qualified(type($ref))";
-  let hasCanonicalizer = true;
 }
 
 def RefSendOp: FIRRTLExprOp<"ref.send", [RefResultTypeConstraint<"base", "result">]> {
@@ -840,7 +839,6 @@ def RefSubOp : FIRRTLExprOp<"ref.sub"> {
 
   let assemblyFormat =
      "$input `[` $index `]` attr-dict `:` qualified(type($input))";
-  let hasCanonicalizer = true;
 }
 
 #endif // CIRCT_DIALECT_FIRRTL_FIRRTLEXPRESSIONS_TD
diff --git a/lib/Dialect/FIRRTL/FIRRTLFolds.cpp b/lib/Dialect/FIRRTL/FIRRTLFolds.cpp
index d8ef5ed47a19..eed2488143e1 100644
--- a/lib/Dialect/FIRRTL/FIRRTLFolds.cpp
+++ b/lib/Dialect/FIRRTL/FIRRTLFolds.cpp
@@ -2818,18 +2818,3 @@ void CoverOp::getCanonicalizationPatterns(RewritePatternSet &results,
                                           MLIRContext *context) {
   results.add(canonicalizeImmediateVerifOp<CoverOp, /* EraseIfZero = */ true>);
 }
-
-//===----------------------------------------------------------------------===//
-// References.
-//===----------------------------------------------------------------------===//
-
-void RefResolveOp::getCanonicalizationPatterns(RewritePatternSet &results,
-                                               MLIRContext *context) {
-  results.insert<patterns::RefResolveOfSend>(context);
-}
-
-void RefSubOp::getCanonicalizationPatterns(RewritePatternSet &results,
-                                           MLIRContext *context) {
-  results.insert<patterns::RefSubOfSendVector, patterns::RefSubOfSendBundle>(
-      context);
-}
diff --git a/test/Dialect/FIRRTL/canonicalization.mlir b/test/Dialect/FIRRTL/canonicalization.mlir
index 8804506af0ce..506cf3b3e82b 100644
--- a/test/Dialect/FIRRTL/canonicalization.mlir
+++ b/test/Dialect/FIRRTL/canonicalization.mlir
@@ -2611,46 +2611,4 @@ firrtl.module @MuxCondWidth(in %cond: !firrtl.uint<1>, out %foo: !firrtl.uint<3>
   firrtl.strictconnect %foo, %0 : !firrtl.uint<3>
 }
 
-// CHECK-LABEL: @RefResolveSend
-firrtl.module @RefResolveSend(in %x: !firrtl.uint<1>, out %y : !firrtl.uint<1>) {
-  // CHECK-NEXT: firrtl.strictconnect %y, %x
-  // CHECK-NEXT: }
-  %ref = firrtl.ref.send %x : !firrtl.uint<1>
-  %res = firrtl.ref.resolve %ref : !firrtl.ref<uint<1>>
-  firrtl.strictconnect %y, %res : !firrtl.uint<1>
-}
-
-// CHECK-LABEL: @RefSubHoistVector
-firrtl.module @RefSubHoistVector(in %x: !firrtl.vector<uint<1>,2>, out %y : !firrtl.ref<uint<1>>) {
-  // CHECK-NEXT: %[[sub:.+]] = firrtl.subindex %x[1]
-  // CHECK-NEXT: %[[ref:.+]] = firrtl.ref.send %[[sub]]
-  // CHECK-NEXT: firrtl.strictconnect %y, %[[ref]]
-  // CHECK-NEXT: }
-  %ref = firrtl.ref.send %x : !firrtl.vector<uint<1>,2>
-  %sub = firrtl.ref.sub %ref[1] : !firrtl.ref<vector<uint<1>,2>>
-  firrtl.strictconnect %y, %sub: !firrtl.ref<uint<1>>
-}
-
-// CHECK-LABEL: @RefSubHoistBundle
-firrtl.module @RefSubHoistBundle(in %x: !firrtl.bundle<a: uint<1>, b: uint<2>>, out %y : !firrtl.ref<uint<2>>) {
-  // CHECK-NEXT: %[[sub:.+]] = firrtl.subfield %x[b]
-  // CHECK-NEXT: %[[ref:.+]] = firrtl.ref.send %[[sub]]
-  // CHECK-NEXT: firrtl.strictconnect %y, %[[ref]]
-  // CHECK-NEXT: }
-  %ref = firrtl.ref.send %x : !firrtl.bundle<a: uint<1>, b: uint<2>>
-  %sub = firrtl.ref.sub %ref[1] : !firrtl.ref<bundle<a: uint<1>, b: uint<2>>>
-  firrtl.strictconnect %y, %sub: !firrtl.ref<uint<2>>
-}
-
-// CHECK-LABEL: @RefResolveSubSend
-firrtl.module private @RefResolveSubSend(in %x: !firrtl.bundle<a: uint<1>, b: uint<2>>, out %y : !firrtl.uint<2>) {
-  // CHECK-NEXT: %[[sub:.+]] = firrtl.subfield %x[b]
-  // CHECK-NEXT: firrtl.strictconnect %y, %[[sub]]
-  // CHECK-NEXT: }
-  %ref = firrtl.ref.send %x : !firrtl.bundle<a: uint<1>, b: uint<2>>
-  %sub = firrtl.ref.sub %ref[1] : !firrtl.ref<bundle<a: uint<1>, b: uint<2>>>
-  %res = firrtl.ref.resolve %sub: !firrtl.ref<uint<2>>
-  firrtl.strictconnect %y, %res : !firrtl.uint<2>
-}
-
 }