[𝘀𝗽𝗿] initial versionupstream/users/vitalybuka/spr/dse-skip-llvmallowruntimeubsancheck

Created using spr 1.3.4

21 files changed, 387 insertions, 1 deletions

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 8bc1cab01bf0..773eb756ed71 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -27696,6 +27696,121 @@ constant `true`. However it is always correct to replace
 it with any other `i1` value. Any pass can
 freely do it if it can benefit from non-default lowering.
 
+'``llvm.allow.ubsan.check``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare i1 @llvm.allow.ubsan.check(i8 immarg %kind)
+
+Overview:
+"""""""""
+
+This intrinsic returns ``true`` if and only if the compiler opted to enable the
+ubsan check in the current basic block.
+
+Rules to allow ubsan checks are not part of the intrinsic declaration, and
+controlled by compiler options.
+
+This intrinsic is the ubsan specific version of ``@llvm.allow.runtime.check()``.
+
+Arguments:
+""""""""""
+
+An integer describing the kind of ubsan check guarded by the intrinsic.
+
+Semantics:
+""""""""""
+
+The intrinsic ``@llvm.allow.ubsan.check()`` returns either ``true`` or
+``false``, depending on compiler options. 
+
+For each evaluation of a call to this intrinsic, the program must be valid and
+correct both if it returns ``true`` and if it returns ``false``.
+
+When used in a branch condition, it allows us to choose between
+two alternative correct solutions for the same problem. 
+
+If the intrinsic is evaluated as ``true``, program must check ubsan condition,
+and report if needed. If the intrinsic is evaluated as ``false``, program must
+avoid checking ubsan condition and assume it passed.
+
+Example:
+
+.. code-block:: text
+
+    %allow = call i1 @llvm.allow.ubsan.check(i8 5)
+    %not.allow = xor i1 %allow, true
+    %cond = or i1 %ubcheck, %not.allow
+    br i1 %cond, label %cont, label %trap
+
+  cont:
+    ; Proceed
+
+  trap:
+    call void @llvm.ubsantrap(i8 5)
+    unreachable
+
+
+'``llvm.allow.runtime.check``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare i1 @llvm.allow.runtime.check(metadata %kind)
+
+Overview:
+"""""""""
+
+This intrinsic returns ``true`` if and only if the compiler opted to enable
+runtime checks in the current basic block.
+
+Rules to allow runtime checks are not part of the intrinsic declaration, and
+controlled by compiler options.
+
+This intrinsic is non-ubsan specific version of ``@llvm.allow.ubsan.check()``.
+
+Arguments:
+""""""""""
+
+A string identifying the kind of runtime check guarded by the intrinsic. The
+string can be used to control rules to allow checks.
+
+Semantics:
+""""""""""
+
+The intrinsic ``@llvm.allow.ubsan.check()`` returns either ``true`` or
+``false``, depending on compiler options. 
+
+For each evaluation of a call to this intrinsic, the program must be valid and
+correct both if it returns ``true`` and if it returns ``false``.
+
+When used in a branch condition, it allows us to choose between
+two alternative correct solutions for the same problem. 
+
+If the intrinsic is evaluated as ``true``, program should execute a guarded
+checks. If the intrinsic is evaluated as ``false``, the program should avoid any
+unnecessary checks.
+
+Example:
+
+.. code-block:: text
+
+    %allow = call i1 @llvm.allow.runtime.check(metadata !"my_check")
+    br i1 %allow, label %fast_path, label %slow_path
+
+  fast_path:
+    ; Omit diagnostics.
+
+  slow_path:
+    ; Additional diagnostics.
+
 
 '``llvm.load.relative``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
index 7c47d3c2338a..63c2ef8912b2 100644
--- a/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
+++ b/llvm/include/llvm/Analysis/TargetTransformInfoImpl.h
@@ -714,6 +714,8 @@ public:
     switch (ICA.getID()) {
     default:
       break;
+    case Intrinsic::allow_runtime_check:
+    case Intrinsic::allow_ubsan_check:
     case Intrinsic::annotation:
     case Intrinsic::assume:
     case Intrinsic::sideeffect:
diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index 091f9b381079..c0c447073799 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -1728,6 +1728,16 @@ def int_debugtrap : Intrinsic<[]>,
 def int_ubsantrap : Intrinsic<[], [llvm_i8_ty],
                               [IntrNoReturn, IntrCold, ImmArg<ArgIndex<0>>]>;
 
+// Return true if ubsan check is allowed.
+def int_allow_ubsan_check : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_i8_ty],
+    [IntrInaccessibleMemOnly, IntrWriteMem, ImmArg<ArgIndex<0>>, NoUndef<RetIndex>]>,
+    ClangBuiltin<"__builtin_allow_ubsan_check">;
+
+// Return true if runtime check is allowed.
+def int_allow_runtime_check : DefaultAttrsIntrinsic<[llvm_i1_ty], [llvm_metadata_ty],
+    [IntrInaccessibleMemOnly, IntrWriteMem, NoUndef<RetIndex>]>,
+    ClangBuiltin<"__builtin_allow_runtime_check">;
+
 // Support for dynamic deoptimization (or de-specialization)
 def int_experimental_deoptimize : Intrinsic<[llvm_any_ty], [llvm_vararg_ty],
                                             [Throws]>;
diff --git a/llvm/lib/Analysis/AliasSetTracker.cpp b/llvm/lib/Analysis/AliasSetTracker.cpp
index 59bb40cdba6e..32e545daaf22 100644
--- a/llvm/lib/Analysis/AliasSetTracker.cpp
+++ b/llvm/lib/Analysis/AliasSetTracker.cpp
@@ -354,6 +354,8 @@ void AliasSetTracker::addUnknown(Instruction *Inst) {
     default:
       break;
       // FIXME: Add lifetime/invariant intrinsics (See: PR30807).
+    case Intrinsic::allow_runtime_check:
+    case Intrinsic::allow_ubsan_check:
     case Intrinsic::assume:
     case Intrinsic::experimental_noalias_scope_decl:
     case Intrinsic::sideeffect:
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
index 82a6c470650c..49450d85d742 100644
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -292,6 +292,8 @@ instructionClobbersQuery(const MemoryDef *MD, const MemoryLocation &UseLoc,
     // clobbers where they don't really exist at all. Please see D43269 for
     // context.
     switch (II->getIntrinsicID()) {
+    case Intrinsic::allow_runtime_check:
+    case Intrinsic::allow_ubsan_check:
     case Intrinsic::invariant_start:
     case Intrinsic::invariant_end:
     case Intrinsic::assume:
@@ -1725,6 +1727,8 @@ MemoryUseOrDef *MemorySSA::createNewAccess(Instruction *I,
     switch (II->getIntrinsicID()) {
     default:
       break;
+    case Intrinsic::allow_runtime_check:
+    case Intrinsic::allow_ubsan_check:
     case Intrinsic::assume:
     case Intrinsic::experimental_noalias_scope_decl:
     case Intrinsic::pseudoprobe:
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 9f99bb7e693f..e657872c3828 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -2462,8 +2462,10 @@ bool CodeGenPrepare::optimizeCallInst(CallInst *CI, ModifyDT &ModifiedDT) {
       break;
     case Intrinsic::assume:
       llvm_unreachable("llvm.assume should have been removed already");
+    case Intrinsic::allow_runtime_check:
+    case Intrinsic::allow_ubsan_check:
     case Intrinsic::experimental_widenable_condition: {
-      // Give up on future widening oppurtunties so that we can fold away dead
+      // Give up on future widening opportunities so that we can fold away dead
       // paths and merge blocks before going into block-local instruction
       // selection.
       if (II->use_empty()) {
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 757af3b1c4fe..0811c5653866 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -2475,6 +2475,11 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
     Info.OrigRet = {Register(), Type::getVoidTy(CI.getContext()), 0};
     return CLI->lowerCall(MIRBuilder, Info);
   }
+  case Intrinsic::allow_runtime_check:
+  case Intrinsic::allow_ubsan_check:
+    MIRBuilder.buildCopy(getOrCreateVReg(CI),
+                         getOrCreateVReg(*ConstantInt::getTrue(CI.getType())));
+    return true;
   case Intrinsic::amdgcn_cs_chain:
     return translateCallBase(CI, MIRBuilder);
   case Intrinsic::fptrunc_round: {
diff --git a/llvm/lib/CodeGen/IntrinsicLowering.cpp b/llvm/lib/CodeGen/IntrinsicLowering.cpp
index 09d282d12c5f..45fba4341ad0 100644
--- a/llvm/lib/CodeGen/IntrinsicLowering.cpp
+++ b/llvm/lib/CodeGen/IntrinsicLowering.cpp
@@ -243,6 +243,11 @@ void IntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
     break;
   }
 
+  case Intrinsic::allow_runtime_check:
+  case Intrinsic::allow_ubsan_check:
+    CI->replaceAllUsesWith(ConstantInt::getTrue(CI->getType()));
+    return;
+
   case Intrinsic::ctpop:
     CI->replaceAllUsesWith(LowerCTPOP(Context, CI->getArgOperand(0), CI));
     break;
diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
index 27b8472ddb73..ce5a7ea09d47 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1452,6 +1452,10 @@ bool FastISel::selectIntrinsicCall(const IntrinsicInst *II) {
   case Intrinsic::is_constant:
     llvm_unreachable("llvm.is.constant.* should have been lowered already");
 
+  case Intrinsic::allow_runtime_check:
+  case Intrinsic::allow_ubsan_check:
+    llvm_unreachable("llvm.*.check should have been lowered already");
+
   case Intrinsic::launder_invariant_group:
   case Intrinsic::strip_invariant_group:
   case Intrinsic::expect: {
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 2d63774c75e3..51c9af6d62d9 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -7322,6 +7322,11 @@ void SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I,
     return;
   }
 
+  case Intrinsic::allow_runtime_check:
+  case Intrinsic::allow_ubsan_check:
+    setValue(&I, getValue(ConstantInt::getTrue(I.getType())));
+    return;
+
   case Intrinsic::uadd_with_overflow:
   case Intrinsic::sadd_with_overflow:
   case Intrinsic::usub_with_overflow:
diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index bfc8bd5970bf..5a9ea420392f 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -760,6 +760,8 @@ namespace {
 bool isNoopIntrinsic(Instruction *I) {
   if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
     switch (II->getIntrinsicID()) {
+    case Intrinsic::allow_runtime_check:
+    case Intrinsic::allow_ubsan_check:
     case Intrinsic::lifetime_start:
     case Intrinsic::lifetime_end:
     case Intrinsic::invariant_end:
diff --git a/llvm/test/Analysis/AliasSet/intrinsics.ll b/llvm/test/Analysis/AliasSet/intrinsics.ll
index 678d6d246e63..0dc802ca7e0a 100644
--- a/llvm/test/Analysis/AliasSet/intrinsics.ll
+++ b/llvm/test/Analysis/AliasSet/intrinsics.ll
@@ -74,6 +74,36 @@ entry:
   ret void
 }
 
+; CHECK: Alias sets for function 'test_runtime':
+; CHECK: Alias Set Tracker: 2 alias sets for 2 pointer values.
+; CHECK:   AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod       Memory locations: (ptr %a, LocationSize::precise(1))
+; CHECK:   AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod       Memory locations: (ptr %b, LocationSize::precise(1))
+define i1 @test_runtime() local_unnamed_addr {
+entry:
+  %a = alloca i8, align 1
+  %b = alloca i8, align 1
+  store i8 1, ptr %a, align 1
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  store i8 1, ptr %b, align 1
+  ret i1 %allow
+}
+
+; CHECK: Alias sets for function 'test_ubsan':
+; CHECK: Alias Set Tracker: 2 alias sets for 2 pointer values.
+; CHECK:   AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod       Memory locations: (ptr %a, LocationSize::precise(1))
+; CHECK:   AliasSet[0x{{[0-9a-f]+}}, 1] must alias, Mod       Memory locations: (ptr %b, LocationSize::precise(1))
+define i1 @test_ubsan() local_unnamed_addr {
+entry:
+  %a = alloca i8, align 1
+  %b = alloca i8, align 1
+  store i8 1, ptr %a, align 1
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  store i8 1, ptr %b, align 1
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8)
+declare i1 @llvm.allow.runtime.check(metadata)
 declare void @llvm.assume(i1)
 declare void @llvm.experimental.guard(i1, ...)
 declare void @llvm.experimental.noalias.scope.decl(metadata)
diff --git a/llvm/test/Analysis/CostModel/free-intrinsics-datalayout.ll b/llvm/test/Analysis/CostModel/free-intrinsics-datalayout.ll
index 4ebb1e314ba1..09fbd68d95e9 100644
--- a/llvm/test/Analysis/CostModel/free-intrinsics-datalayout.ll
+++ b/llvm/test/Analysis/CostModel/free-intrinsics-datalayout.ll
@@ -25,6 +25,8 @@ define i32 @trivially_free() {
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: call void @llvm.lifetime.end.p0(i64 1, ptr undef)
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a5 = call i64 @llvm.objectsize.i64.p0(ptr undef, i1 true, i1 true, i1 true)
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a6 = call ptr @llvm.ptr.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
+; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a7 = call i1 @llvm.allow.ubsan.check(i8 123)
+; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a8 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: call void @llvm.var.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret i32 undef
 ;
@@ -45,6 +47,8 @@ define i32 @trivially_free() {
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: call void @llvm.lifetime.end.p0(i64 1, ptr undef)
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a5 = call i64 @llvm.objectsize.i64.p0(ptr undef, i1 true, i1 true, i1 true)
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a6 = call ptr @llvm.ptr.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
+; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a7 = call i1 @llvm.allow.ubsan.check(i8 123)
+; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a8 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: call void @llvm.var.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret i32 undef
 ;
@@ -65,6 +69,8 @@ define i32 @trivially_free() {
   call void @llvm.lifetime.end.p0(i64 1, ptr undef)
   %a5 = call i64 @llvm.objectsize.i64.p0(ptr undef, i1 1, i1 1, i1 1)
   %a6 = call ptr @llvm.ptr.annotation.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
+  %a7 = call i1 @llvm.allow.ubsan.check(i8 123)
+  %a8 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
   call void @llvm.var.annotation(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
   ret i32 undef
 }
diff --git a/llvm/test/Analysis/CostModel/free-intrinsics-no_info.ll b/llvm/test/Analysis/CostModel/free-intrinsics-no_info.ll
index 5d47e4894427..3e78c62a6fe2 100644
--- a/llvm/test/Analysis/CostModel/free-intrinsics-no_info.ll
+++ b/llvm/test/Analysis/CostModel/free-intrinsics-no_info.ll
@@ -24,6 +24,8 @@ define i32 @trivially_free() {
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a5 = call i64 @llvm.objectsize.i64.p0(ptr undef, i1 true, i1 true, i1 true)
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a6 = call ptr @llvm.ptr.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: call void @llvm.var.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
+; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a7 = call i1 @llvm.allow.ubsan.check(i8 123)
+; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a8 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
 ; CHECK-SIZE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret i32 undef
 ;
 ; CHECK-THROUGHPUT-LABEL: 'trivially_free'
@@ -44,6 +46,8 @@ define i32 @trivially_free() {
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a5 = call i64 @llvm.objectsize.i64.p0(ptr undef, i1 true, i1 true, i1 true)
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a6 = call ptr @llvm.ptr.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: call void @llvm.var.annotation.p0.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
+; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a7 = call i1 @llvm.allow.ubsan.check(i8 123)
+; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a8 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
 ; CHECK-THROUGHPUT-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret i32 undef
 ;
   %a0 = call i32 @llvm.annotation.i32(i32 undef, ptr undef, ptr undef, i32 undef)
@@ -64,6 +68,8 @@ define i32 @trivially_free() {
   %a5 = call i64 @llvm.objectsize.i64.p0(ptr undef, i1 1, i1 1, i1 1)
   %a6 = call ptr @llvm.ptr.annotation.p0(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
   call void @llvm.var.annotation(ptr undef, ptr undef, ptr undef, i32 undef, ptr undef)
+  %a7 = call i1 @llvm.allow.ubsan.check(i8 123)
+  %a8 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
   ret i32 undef
 }
 
diff --git a/llvm/test/Analysis/MemorySSA/allow-check.ll b/llvm/test/Analysis/MemorySSA/allow-check.ll
new file mode 100644
index 000000000000..dcdad001ca6f
--- /dev/null
+++ b/llvm/test/Analysis/MemorySSA/allow-check.ll
@@ -0,0 +1,29 @@
+; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>,verify<memoryssa>' -disable-output < %s 2>&1 | FileCheck %s --implicit-check-not=MemoryDef
+;
+; Ensures that allow.*.check are treated as not reading or writing memory.
+
+target triple = "aarch64-linux"
+
+define i1 @test_runtime(ptr %a) local_unnamed_addr {
+entry:
+; CHECK: 1 = MemoryDef(liveOnEntry)
+  store i32 4, ptr %a, align 4
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  %0 = load i32, ptr %a, align 4
+; CHECK: MemoryUse(1)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.runtime.check(metadata)
+
+define i1 @test_ubsan(ptr %a) local_unnamed_addr {
+entry:
+; CHECK: 1 = MemoryDef(liveOnEntry)
+  store i32 4, ptr %a, align 4
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  %0 = load i32, ptr %a, align 4
+; CHECK: MemoryUse(1)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8)
diff --git a/llvm/test/CodeGen/AArch64/allow-check.ll b/llvm/test/CodeGen/AArch64/allow-check.ll
new file mode 100644
index 000000000000..c315b216e222
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/allow-check.ll
@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc < %s -mtriple=aarch64 | FileCheck %s
+; RUN: llc < %s -mtriple=aarch64 -global-isel | FileCheck %s
+; RUN: llc < %s -mtriple=aarch64 -fast-isel | FileCheck %s
+
+target triple = "aarch64-linux"
+
+define i1 @test_runtime() local_unnamed_addr {
+; CHECK-LABEL: test_runtime:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w0, #1 // =0x1
+; CHECK-NEXT:    ret
+entry:
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.runtime.check(metadata) nounwind
+
+define i1 @test_ubsan() local_unnamed_addr {
+; CHECK-LABEL: test_ubsan:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    mov w0, #1 // =0x1
+; CHECK-NEXT:    ret
+entry:
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8) nounwind
diff --git a/llvm/test/CodeGen/AMDGPU/allow-check.ll b/llvm/test/CodeGen/AMDGPU/allow-check.ll
new file mode 100644
index 000000000000..db6cdc30493d
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/allow-check.ll
@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc < %s -mtriple=amdgcn-amd-mesa3d | FileCheck %s
+; RUN: llc < %s -mtriple=amdgcn-amd-mesa3d -global-isel | FileCheck %s
+; RUN: llc < %s -mtriple=amdgcn-amd-mesa3d -fast-isel | FileCheck %s
+
+define i1 @test_runtime() local_unnamed_addr {
+; CHECK-LABEL: test_runtime:
+; CHECK:       ; %bb.0: ; %entry
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    v_mov_b32_e32 v0, 1
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+entry:
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.runtime.check(metadata) nounwind
+
+define i1 @test_ubsan() local_unnamed_addr {
+; CHECK-LABEL: test_ubsan:
+; CHECK:       ; %bb.0: ; %entry
+; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; CHECK-NEXT:    v_mov_b32_e32 v0, 1
+; CHECK-NEXT:    s_setpc_b64 s[30:31]
+entry:
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8) nounwind
diff --git a/llvm/test/CodeGen/Generic/allow-check.ll b/llvm/test/CodeGen/Generic/allow-check.ll
new file mode 100644
index 000000000000..88412f552d13
--- /dev/null
+++ b/llvm/test/CodeGen/Generic/allow-check.ll
@@ -0,0 +1,23 @@
+; RUN: llc < %s -O3
+; RUN: llc < %s -O3 -global-isel
+; RUN: llc < %s -O3 -fast-isel
+
+; RUN: llc < %s -O0
+; RUN: llc < %s -O0 -global-isel
+; RUN: llc < %s -O0 -fast-isel
+
+define i1 @test_runtime() local_unnamed_addr {
+entry:
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.runtime.check(metadata) nounwind
+
+define i1 @test_ubsan() local_unnamed_addr {
+entry:
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8) nounwind
diff --git a/llvm/test/CodeGen/RISCV/allow-check.ll b/llvm/test/CodeGen/RISCV/allow-check.ll
new file mode 100644
index 000000000000..2ac6370adbd5
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/allow-check.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=riscv32 | FileCheck %s
+; RUN: llc < %s -mtriple=riscv64 | FileCheck %s
+; RUN: llc < %s -mtriple=riscv32 -global-isel | FileCheck %s
+; RUN: llc < %s -mtriple=riscv64 -global-isel | FileCheck %s
+; RUN: llc < %s -mtriple=riscv32 -fast-isel=true | FileCheck %s
+; RUN: llc < %s -mtriple=riscv64 -fast-isel=true | FileCheck %s
+
+define i1 @test_runtime() local_unnamed_addr {
+; CHECK-LABEL: test_runtime:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    li a0, 1
+; CHECK-NEXT:    ret
+entry:
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.runtime.check(metadata) nounwind
+
+define i1 @test_ubsan() local_unnamed_addr {
+; CHECK-LABEL: test_ubsan:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    li a0, 1
+; CHECK-NEXT:    ret
+entry:
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8) nounwind
diff --git a/llvm/test/CodeGen/X86/allow-check.ll b/llvm/test/CodeGen/X86/allow-check.ll
new file mode 100644
index 000000000000..3f0bb1837b22
--- /dev/null
+++ b/llvm/test/CodeGen/X86/allow-check.ll
@@ -0,0 +1,28 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 4
+; RUN: llc < %s -mtriple=x86_64 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64 -global-isel | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64 -fast-isel | FileCheck %s
+
+define i1 @test_runtime() local_unnamed_addr {
+; CHECK-LABEL: test_runtime:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movb $1, %al
+; CHECK-NEXT:    retq
+entry:
+  %allow = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.runtime.check(metadata) nounwind
+
+define i1 @test_ubsan() local_unnamed_addr {
+; CHECK-LABEL: test_ubsan:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    movb $1, %al
+; CHECK-NEXT:    retq
+entry:
+  %allow = call i1 @llvm.allow.ubsan.check(i8 7)
+  ret i1 %allow
+}
+
+declare i1 @llvm.allow.ubsan.check(i8) nounwind
diff --git a/llvm/test/Transforms/DeadStoreElimination/libcalls.ll b/llvm/test/Transforms/DeadStoreElimination/libcalls.ll
index 4d9a767e08d4..7a4908d550a9 100644
--- a/llvm/test/Transforms/DeadStoreElimination/libcalls.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/libcalls.ll
@@ -487,3 +487,20 @@ define void @dse_strncpy_test6(ptr noalias %out1, ptr noalias %out2, ptr noalias
   %call = tail call ptr @strncpy(ptr %out2, ptr %in, i64 100)
   ret void
 }
+
+define i32 @test_strcat_with_allow_check(ptr %src) {
+; CHECK-LABEL: @test_strcat_with_allow_check(
+; CHECK-NEXT:    [[ALLOW1:%.*]] = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+; CHECK-NEXT:    [[ALLOW2:%.*]] = call i1 @llvm.allow.ubsan.check(i8 7)
+; CHECK-NEXT:    tail call void @llvm.memset.p0.i64(ptr [[B:%.*]], i8 44, i64 16, i1 false)
+; CHECK-NEXT:    [[RET:%.*]] = load i32, ptr [[B]], align 4
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  tail call void @llvm.memset.p0.i64(ptr %src, i8 42, i64 16, i1 false)
+  %allow1 = call i1 @llvm.allow.runtime.check(metadata !"test_check")
+  tail call void @llvm.memset.p0.i64(ptr %src, i8 43, i64 16, i1 false)
+  %allow2 = call i1 @llvm.allow.ubsan.check(i8 7)
+  tail call void @llvm.memset.p0.i64(ptr %src, i8 44, i64 16, i1 false)
+  %ret = load i32, ptr %src, align 4
+  ret i32 %ret
+}