Reland [EquivClasses] Introduce members iterator-helper (#130319)

Changes: Fix the expectations in EquivalenceClassesTest.MemberIterator,
also fixing a build failure.

Author: artagnon

llvm/include/llvm/ADT/EquivalenceClasses.h

@@ -15,6 +15,7 @@
 #ifndef LLVM_ADT_EQUIVALENCECLASSES_H
 #define LLVM_ADT_EQUIVALENCECLASSES_H
 
+#include "llvm/ADT/iterator_range.h"
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
@@ -178,6 +179,9 @@ class EquivalenceClasses {
   member_iterator member_end() const {
     return member_iterator(nullptr);
   }
+  iterator_range<member_iterator> members(iterator I) const {
+    return make_range(member_begin(I), member_end());
+  }
 
   /// findValue - Return an iterator to the specified value.  If it does not
   /// exist, end() is returned.

llvm/lib/Analysis/LoopAccessAnalysis.cpp

@@ -527,9 +527,8 @@ void RuntimePointerChecking::groupChecks(
     // iteration order within an equivalence class member is only dependent on
     // the order in which unions and insertions are performed on the
     // equivalence class, the iteration order is deterministic.
-    for (auto MI = DepCands.member_begin(LeaderI), ME = DepCands.member_end();
-         MI != ME; ++MI) {
-      auto PointerI = PositionMap.find(MI->getPointer());
+    for (const auto &MI : DepCands.members(LeaderI)) {
+      auto PointerI = PositionMap.find(MI.getPointer());
       assert(PointerI != PositionMap.end() &&
              "pointer in equivalence class not found in PositionMap");
       for (unsigned Pointer : PointerI->second) {

llvm/lib/Analysis/VectorUtils.cpp

@@ -845,7 +845,7 @@ llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB,
 
   for (auto I = ECs.begin(), E = ECs.end(); I != E; ++I) {
     uint64_t LeaderDemandedBits = 0;
-    for (Value *M : llvm::make_range(ECs.member_begin(I), ECs.member_end()))
+    for (Value *M : ECs.members(I))
       LeaderDemandedBits |= DBits[M];
 
     uint64_t MinBW = llvm::bit_width(LeaderDemandedBits);
@@ -857,15 +857,15 @@ llvm::computeMinimumValueSizes(ArrayRef<BasicBlock *> Blocks, DemandedBits &DB,
     // indvars.
     // If we are required to shrink a PHI, abandon this entire equivalence class.
     bool Abort = false;
-    for (Value *M : llvm::make_range(ECs.member_begin(I), ECs.member_end()))
+    for (Value *M : ECs.members(I))
       if (isa<PHINode>(M) && MinBW < M->getType()->getScalarSizeInBits()) {
         Abort = true;
         break;
       }
     if (Abort)
       continue;
 
-    for (Value *M : llvm::make_range(ECs.member_begin(I), ECs.member_end())) {
+    for (Value *M : ECs.members(I)) {
       auto *MI = dyn_cast<Instruction>(M);
       if (!MI)
         continue;

llvm/unittests/ADT/EquivalenceClassesTest.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/ADT/EquivalenceClasses.h"
+#include "gmock/gmock.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
@@ -66,6 +67,19 @@ TEST(EquivalenceClassesTest, TwoSets) {
         EXPECT_FALSE(EqClasses.isEquivalent(i, j));
 }
 
+TEST(EquivalenceClassesTest, MembersIterator) {
+  EquivalenceClasses<int> EC;
+  EC.unionSets(1, 2);
+  EC.insert(4);
+  EC.insert(5);
+  EC.unionSets(5, 1);
+  EXPECT_EQ(EC.getNumClasses(), 2u);
+
+  EquivalenceClasses<int>::iterator I = EC.findValue(EC.getLeaderValue(1));
+  EXPECT_THAT(EC.members(I), testing::ElementsAre(5, 1, 2));
+  EXPECT_EQ(EC.members(EC.end()).begin(), EC.member_end());
+}
+
 // Type-parameterized tests: Run the same test cases with different element
 // types.
 template <typename T> class ParameterizedTest : public testing::Test {};