[GVN] Also remove phi nodes from VN table (PR65447)

Followup to D158849: We also need to remove the phi node from the
VN table, which is not handled by removeInstruction().

Fixes #65447.

(cherry picked from commit 18e7776)

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -2780,8 +2780,10 @@ bool GVNPass::processBlock(BasicBlock *BB) {
   // identical phis, and the second or later passes can eliminate them.
   SmallPtrSet<PHINode *, 8> PHINodesToRemove;
   ChangedFunction |= EliminateDuplicatePHINodes(BB, PHINodesToRemove);
-  for (PHINode *PN : PHINodesToRemove)
+  for (PHINode *PN : PHINodesToRemove) {
+    VN.erase(PN);
     removeInstruction(PN);
+  }
 
   for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
        BI != BE;) {

llvm/test/Transforms/GVN/pr65447.ll

@@ -0,0 +1,71 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 3
+; RUN: opt -S -passes=gvn < %s | FileCheck %s
+
+; Make sure deduplicated phi nodes are removed from the VN map.
+define i64 @f() {
+; CHECK-LABEL: define i64 @f() {
+; CHECK-NEXT:  BB:
+; CHECK-NEXT:    store i1 false, ptr null, align 1
+; CHECK-NEXT:    br label [[BB2D:%.*]]
+; CHECK:       BB2a:
+; CHECK-NEXT:    br label [[BB2B:%.*]]
+; CHECK:       BB2b:
+; CHECK-NEXT:    [[L93_PRE_PRE:%.*]] = load i1, ptr inttoptr (i64 -1 to ptr), align 1
+; CHECK-NEXT:    br label [[BB2C:%.*]]
+; CHECK:       BB2c:
+; CHECK-NEXT:    [[L93_PRE:%.*]] = phi i1 [ [[L93_PRE_PRE]], [[BB2B]] ], [ true, [[BB2D]] ]
+; CHECK-NEXT:    [[AZ2:%.*]] = phi i1 [ true, [[BB2B]] ], [ [[AZ:%.*]], [[BB2D]] ]
+; CHECK-NEXT:    [[DOTPHI_TRANS_INSERT:%.*]] = sext i1 [[AZ2]] to i64
+; CHECK-NEXT:    [[GEP2_PHI_TRANS_INSERT:%.*]] = getelementptr i1, ptr null, i64 [[DOTPHI_TRANS_INSERT]]
+; CHECK-NEXT:    br label [[BB2D]]
+; CHECK:       BB2d:
+; CHECK-NEXT:    [[L93_PRE5:%.*]] = phi i1 [ [[L93_PRE]], [[BB2C]] ], [ false, [[BB:%.*]] ]
+; CHECK-NEXT:    [[AZ]] = phi i1 [ [[AZ2]], [[BB2C]] ], [ false, [[BB]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = sext i1 [[AZ]] to i64
+; CHECK-NEXT:    [[GEP2:%.*]] = getelementptr i1, ptr null, i64 [[TMP0]]
+; CHECK-NEXT:    store i1 [[AZ]], ptr null, align 2
+; CHECK-NEXT:    br i1 [[L93_PRE5]], label [[BB2C]], label [[BB1E:%.*]]
+; CHECK:       BB1e:
+; CHECK-NEXT:    br i1 [[AZ]], label [[BB2F:%.*]], label [[BB4:%.*]]
+; CHECK:       BB2f:
+; CHECK-NEXT:    store i1 true, ptr null, align 2
+; CHECK-NEXT:    br label [[BB2B]]
+; CHECK:       BB4:
+; CHECK-NEXT:    br label [[BB4]]
+;
+BB:
+  store i1 false, ptr null, align 1
+  br label %BB2d
+
+BB2a: ; No predecessors!
+  br label %BB2b
+
+BB2b:       ; preds = %BB2f, %BB2a
+  br label %BB2c
+
+BB2c:                     ; preds = %BB2d, %BB2b
+  %0 = phi i1 [ true, %BB2b ], [ %1, %BB2d ]
+  br label %BB2d
+
+BB2d:                              ; preds = %BB2c, %BB
+  %1 = phi i1 [ %0, %BB2c ], [ false, %BB ]
+  %2 = sext i1 %1 to i64
+  %gep2 = getelementptr i1, ptr null, i64 %2
+  %L93 = load i1, ptr %gep2, align 1
+  %Az = load i1, ptr null, align 2
+  store i1 %1, ptr null, align 2
+  br i1 %L93, label %BB2c, label %BB1e
+
+BB1e:                                        ; preds = %BB2d
+  br i1 %Az, label %BB2f, label %BB4
+
+BB2f:                                ; preds = %BB1e
+  store i1 true, ptr null, align 2
+  br label %BB2b
+
+BB4:                                              ; preds = %BB1e, %BB4
+  br label %BB4
+
+; uselistorder directives
+  uselistorder label %BB4, { 1, 0 }
+}