[llvm] Revert "[PatternMatch] Fix issue of stale reference in new `m_{I,F,}Cmp` matchers" (PR #99062)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka created https://github.com/llvm/llvm-project/pull/99062

Reverts llvm/llvm-project#98866

It's still use-after-scope.

>From ddc8e9d34306177966a3f46e8eefc3d4a0c7c8ef Mon Sep 17 00:00:00 2001
From: Vitaly Buka <vitalybuka at gmail.com>
Date: Tue, 16 Jul 2024 09:53:13 -0700
Subject: [PATCH] =?UTF-8?q?Revert=20"[PatternMatch]=20Fix=20issue=20of=20s?=
 =?UTF-8?q?tale=20reference=20in=20new=20`m=5F{I,F,}Cmp`=20matc=E2=80=A6"?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This reverts commit e027017337cc8ae6ed03dc2a3d1c9903ea2f33b2.
---
 llvm/include/llvm/IR/PatternMatch.h | 21 ++++++++++-----------
 llvm/unittests/IR/PatternMatch.cpp  |  4 ++--
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/llvm/include/llvm/IR/PatternMatch.h b/llvm/include/llvm/IR/PatternMatch.h
index bea1ad97ea09c..8ae47fb556b25 100644
--- a/llvm/include/llvm/IR/PatternMatch.h
+++ b/llvm/include/llvm/IR/PatternMatch.h
@@ -1550,27 +1550,23 @@ template <typename T> inline Exact_match<T> m_Exact(const T &SubPattern) {
 template <typename LHS_t, typename RHS_t, typename Class, typename PredicateTy,
           bool Commutable = false>
 struct CmpClass_match {
-  PredicateTy *Predicate;
+  PredicateTy &Predicate;
   LHS_t L;
   RHS_t R;
 
   // The evaluation order is always stable, regardless of Commutability.
   // The LHS is always matched first.
   CmpClass_match(PredicateTy &Pred, const LHS_t &LHS, const RHS_t &RHS)
-      : Predicate(&Pred), L(LHS), R(RHS) {}
-  CmpClass_match(const LHS_t &LHS, const RHS_t &RHS)
-      : Predicate(nullptr), L(LHS), R(RHS) {}
+      : Predicate(Pred), L(LHS), R(RHS) {}
 
   template <typename OpTy> bool match(OpTy *V) {
     if (auto *I = dyn_cast<Class>(V)) {
       if (L.match(I->getOperand(0)) && R.match(I->getOperand(1))) {
-        if (Predicate)
-          *Predicate = I->getPredicate();
+        Predicate = I->getPredicate();
         return true;
       } else if (Commutable && L.match(I->getOperand(1)) &&
                  R.match(I->getOperand(0))) {
-        if (Predicate)
-          *Predicate = I->getSwappedPredicate();
+        Predicate = I->getSwappedPredicate();
         return true;
       }
     }
@@ -1599,19 +1595,22 @@ m_FCmp(FCmpInst::Predicate &Pred, const LHS &L, const RHS &R) {
 template <typename LHS, typename RHS>
 inline CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>
 m_Cmp(const LHS &L, const RHS &R) {
-  return CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>(L, R);
+  CmpInst::Predicate Unused;
+  return CmpClass_match<LHS, RHS, CmpInst, CmpInst::Predicate>(Unused, L, R);
 }
 
 template <typename LHS, typename RHS>
 inline CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>
 m_ICmp(const LHS &L, const RHS &R) {
-  return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>(L, R);
+  ICmpInst::Predicate Unused;
+  return CmpClass_match<LHS, RHS, ICmpInst, ICmpInst::Predicate>(Unused, L, R);
 }
 
 template <typename LHS, typename RHS>
 inline CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>
 m_FCmp(const LHS &L, const RHS &R) {
-  return CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>(L, R);
+  FCmpInst::Predicate Unused;
+  return CmpClass_match<LHS, RHS, FCmpInst, FCmpInst::Predicate>(Unused, L, R);
 }
 
 // Same as CmpClass, but instead of saving Pred as out output variable, match a
diff --git a/llvm/unittests/IR/PatternMatch.cpp b/llvm/unittests/IR/PatternMatch.cpp
index 309fcc93996bc..b82711ec244a6 100644
--- a/llvm/unittests/IR/PatternMatch.cpp
+++ b/llvm/unittests/IR/PatternMatch.cpp
@@ -2235,7 +2235,7 @@ typedef ::testing::Types<std::tuple<Value*, Instruction*>,
     MutableConstTestTypes;
 TYPED_TEST_SUITE(MutableConstTest, MutableConstTestTypes, );
 
-TYPED_TEST(MutableConstTest, ICmp) {
+TYPED_TEST(MutableConstTest, /* FIXME: UAR bug */ DISABLED_ICmp) {
   auto &IRB = PatternMatchTest::IRB;
 
   typedef std::tuple_element_t<0, TypeParam> ValueType;
@@ -2319,7 +2319,7 @@ TYPED_TEST(MutableConstTest, ICmp) {
                    .match((InstructionType)IRB.CreateICmp(Pred, L, R)));
 }
 
-TYPED_TEST(MutableConstTest, FCmp) {
+TYPED_TEST(MutableConstTest, /* FIXME: UAR bug */ DISABLED_FCmp) {
   auto &IRB = PatternMatchTest::IRB;
 
   typedef std::tuple_element_t<0, TypeParam> ValueType;