From 1acd9a1a29ac30044ecefb6613485d5d168f66ca Mon Sep 17 00:00:00 2001
From: Roman Lebedev <lebedev.ri@gmail.com>
Date: Sat, 8 May 2021 15:42:11 +0300
Subject: [PATCH] Revert "[LICM] Hoist loads with invariant.group metadata"

This appears to miscompile google benchmark's GetCacheSizesFromKVFS()
when compiling with -fstrict-vtable-pointers.
Runnable reproducer: https://godbolt.org/z/f9ovKqTzb
The "f.fail()" crashes with BUS error, it is compiled into testb,
and the adress it is testing is non-sensical.

This reverts commit 4c89bcadf6cae8320a1925eb9cbeb8c8c1f5f58b.
---
 llvm/lib/Transforms/Scalar/LICM.cpp          |  4 --
 llvm/test/Transforms/LICM/invariant.group.ll | 58 ----------------------------
 2 files changed, 62 deletions(-)
 delete mode 100644 llvm/test/Transforms/LICM/invariant.group.ll

diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index c2bc93c..a2bda9d 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -1198,10 +1198,6 @@ bool llvm::canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
     if (isLoadInvariantInLoop(LI, DT, CurLoop))
       return true;
 
-    // Stores with an invariant.group metadata are ok to sink/hoist.
-    if (LI->hasMetadata(LLVMContext::MD_invariant_group))
-      return true;
-
     bool Invalidated;
     if (CurAST)
       Invalidated = pointerInvalidatedByLoop(MemoryLocation::get(LI), CurAST,
diff --git a/llvm/test/Transforms/LICM/invariant.group.ll b/llvm/test/Transforms/LICM/invariant.group.ll
deleted file mode 100644
index 0d33ac1..0000000
--- a/llvm/test/Transforms/LICM/invariant.group.ll
+++ /dev/null
@@ -1,58 +0,0 @@
-; RUN: opt -S < %s -passes=licm | FileCheck %s
-
-declare i8* @llvm.launder.invariant.group.p0i8(i8* %a)
-
-; CHECK-LABEL: define{{.*}}@f
-define void @f(i32* %x) {
-; CHECK: entry:
-; CHECK-NOT: {{.*}}:
-; CHECK: load {{.*}} !invariant.group
-entry:
-  %x_i8 = bitcast i32* %x to i8*
-  %x_i8_inv = call i8* @llvm.launder.invariant.group.p0i8(i8* %x_i8)
-  br label %for.body
-
-for.cond.cleanup:
-  ret void
-
-for.body:
-  %i.04 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
-
-  %x_inv = bitcast i8* %x_i8_inv to i32*
-  %0 = load i32, i32* %x_inv, !invariant.group !0
-
-  call void @a(i32 %0)
-  %inc = add nuw nsw i32 %i.04, 1
-  %exitcond.not = icmp eq i32 %inc, 100
-  br i1 %exitcond.not, label %for.cond.cleanup, label %for.body
-}
-
-; CHECK-LABEL: define{{.*}}@g
-define void @g(i32* %x) {
-; CHECK: for.body:
-; CHECK-NOT: {{.*}}:
-; CHECK: load {{.*}} !invariant.group
-entry:
-  %x_i8 = bitcast i32* %x to i8*
-  br label %for.body
-
-for.cond.cleanup:
-  ret void
-
-for.body:
-  %i.04 = phi i32 [ 0, %entry ], [ %inc, %for.body ]
-
-  %x_i8_inv = call i8* @llvm.launder.invariant.group.p0i8(i8* %x_i8)
-  %x_inv = bitcast i8* %x_i8_inv to i32*
-
-  %0 = load i32, i32* %x_inv, !invariant.group !0
-
-  call void @a(i32 %0)
-  %inc = add nuw nsw i32 %i.04, 1
-  %exitcond.not = icmp eq i32 %inc, 100
-  br i1 %exitcond.not, label %for.cond.cleanup, label %for.body
-}
-
-declare void @a(i32)
-
-!0 = !{}
-- 
2.7.4