[MemDep] Don't use cached results from a previous larger query

[sunfish]

Summary

When a memdep query finds a cached result from a previous query that had a larger size, don't reuse the cached results, because aliasing queries with a greater size aren't always more conservative. For example, BasicAA knows that accesses larger than the size of underlying objects don't alias those objects.

This could increase compile time in the case of many queries to the same pointer with successively smaller sizes, though this is uncommon.

Fixes PR35519.

[sanjoy]

lib/Analysis/MemoryDependenceAnalysis.cpp

1129 ↗

(On Diff #125405)

You can still use the result if CacheInfo->Size is UnknownSize, right?

And, secondly, any reason to not add the size to the cache key as well?

[sunfish]

This adds a fix for the testcase reported in PR35519; see the change in MemCpyOptimizer.cpp. The code for merging stores into a memset wasn't properly updating memdep's query cache.

This isn't ready for final review yet:

• I plan to add a reduced testcase. (It's complex to write as the bug requires a specific sequence of events -- one optimization happens in a way that leaves the cache in an incorrect state, then a second optimization relies on the cache).
• I plan to address @sanjoy's review feedback.

[sunfish]

• Fixes debug info updating.
• Adds a proper testcase for the memset merging caching bug.

[sunfish]

lib/Analysis/MemoryDependenceAnalysis.cpp

1129 ↗

(On Diff #125405)

Yes, I think reusing the result from an UnknownSize query would be conservatively correct, though it would be less precise. Also, yes, we could add the size, and the AATags too for that matter, to the key, however it would make the DenseMap use more memory.

My expectation, which seems supported by some ad-hoc experiments, is that repeated queries with the same pointer and differing sizes aren't very common. Assuming this is true in general, it seems best to avoid pessimizing common cases to optimize it.

[sunfish]

The issue reported in PR35519 is now fixed, there's a testcase now, and I responded to @sanjoy's comment above.

[hfinkel]

LGTM

This is a pretty awful implicit contract. Hopefully, we'll update this pass to use MemorySSA soon.

lib/Transforms/Scalar/MemCpyOptimizer.cpp

495 ↗

(On Diff #125780)

Please include the fact that you're talking about MemDep here, such as:

... on the removed instructions in MemoryDependenceAnalysis, the...

[sunfish]

lib/Transforms/Scalar/MemCpyOptimizer.cpp

495 ↗

(On Diff #125780)

Done.

llvm/trunk/include/llvm/Analysis/MemoryDependenceAnalysis.h

public:
   /// accurate, and thus usable for reordering, but it is never legal to
   /// remove the query instruction.
   ///
   /// This method assumes the pointer has a "NonLocal" dependency within
   /// QueryInst's parent basic block.
   void getNonLocalPointerDependency(Instruction *QueryInst,
                                     SmallVectorImpl<NonLocalDepResult> &Result);
 
+  /// Perform a dependency query specifically for QueryInst's access to Loc.
+  /// The other comments for getNonLocalPointerDependency apply here as well.
+  void getNonLocalPointerDependencyFrom(Instruction *QueryInst,
+                                        const MemoryLocation &Loc, bool isLoad,
+                                        SmallVectorImpl<NonLocalDepResult> &Result);
+
   /// Removes an instruction from the dependence analysis, updating the
   /// dependence of instructions that previously depended on it.
   void removeInstruction(Instruction *InstToRemove);
 
   /// Invalidates cached information about the specified pointer, because it
   /// may be too conservative in memdep.
   ///
   /// This is an optional call that can be used when the client detects an

llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp

MemoryDependenceResults::getNonLocalCallDependency(CallSite QueryCS) {
 
   return Cache;
 }
 
 void MemoryDependenceResults::getNonLocalPointerDependency(
     Instruction *QueryInst, SmallVectorImpl<NonLocalDepResult> &Result) {
   const MemoryLocation Loc = MemoryLocation::get(QueryInst);
   bool isLoad = isa<LoadInst>(QueryInst);
+  return getNonLocalPointerDependencyFrom(QueryInst, Loc, isLoad, Result);
+}
+
+void MemoryDependenceResults::getNonLocalPointerDependencyFrom(
+    Instruction *QueryInst,
+    const MemoryLocation &Loc,
+    bool isLoad,
+    SmallVectorImpl<NonLocalDepResult> &Result) {
   BasicBlock *FromBB = QueryInst->getParent();
   assert(FromBB);
 
   assert(Loc.Ptr->getType()->isPointerTy() &&
          "Can't get pointer deps of a non-pointer!");
   Result.clear();
   {
     // Check if there is cached Def with invariant.group. FIXME: cache might be
bool MemoryDependenceResults::getNonLocalPointerDepFromBB(
   // already have one.
   std::pair<CachedNonLocalPointerInfo::iterator, bool> Pair =
       NonLocalPointerDeps.insert(std::make_pair(CacheKey, InitialNLPI));
   NonLocalPointerInfo *CacheInfo = &Pair.first->second;
 
   // If we already have a cache entry for this CacheKey, we may need to do some
   // work to reconcile the cache entry and the current query.
   if (!Pair.second) {
-    if (CacheInfo->Size < Loc.Size) {
-      // The query's Size is greater than the cached one. Throw out the
-      // cached data and proceed with the query at the greater size.
+    if (CacheInfo->Size != Loc.Size) {
+      // The query's Size differs from the cached one. Throw out the
+      // cached data and proceed with the query at the new size.
       CacheInfo->Pair = BBSkipFirstBlockPair();
       CacheInfo->Size = Loc.Size;
       for (auto &Entry : CacheInfo->NonLocalDeps)
         if (Instruction *Inst = Entry.getResult().getInst())
           RemoveFromReverseMap(ReverseNonLocalPtrDeps, Inst, CacheKey);
       CacheInfo->NonLocalDeps.clear();
-    } else if (CacheInfo->Size > Loc.Size) {
-      // This query's Size is less than the cached one. Conservatively restart
-      // the query using the greater size.
-      return getNonLocalPointerDepFromBB(
-          QueryInst, Pointer, Loc.getWithNewSize(CacheInfo->Size), isLoad,
-          StartBB, Result, Visited, SkipFirstBlock);
     }
 
     // If the query's AATags are inconsistent with the cached one,
     // conservatively throw out the cached data and restart the query with
     // no tag if needed.
     if (CacheInfo->AATags != Loc.AATags) {
       if (CacheInfo->AATags) {
         CacheInfo->Pair = BBSkipFirstBlockPair();

llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp

for (const MemsetRange &Range : Ranges) {
     // Determine alignment
     unsigned Alignment = Range.Alignment;
     if (Alignment == 0) {
       Type *EltType =
         cast<PointerType>(StartPtr->getType())->getElementType();
       Alignment = DL.getABITypeAlignment(EltType);
     }
 
-    AMemSet =
-      Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start, Alignment);
+    // Remember the debug location.
+    DebugLoc Loc;
+    if (!Range.TheStores.empty())
+      Loc = Range.TheStores[0]->getDebugLoc();
 
     DEBUG(dbgs() << "Replace stores:\n";
           for (Instruction *SI : Range.TheStores)
-            dbgs() << *SI << '\n';
-          dbgs() << "With: " << *AMemSet << '\n');
-
-    if (!Range.TheStores.empty())
-      AMemSet->setDebugLoc(Range.TheStores[0]->getDebugLoc());
+            dbgs() << *SI << '\n');
 
     // Zap all the stores.
     for (Instruction *SI : Range.TheStores) {
       MD->removeInstruction(SI);
       SI->eraseFromParent();
     }
+
+    // Create the memset after removing the stores, so that if there any cached
+    // non-local dependencies on the removed instructions in
+    // MemoryDependenceAnalysis, the cache entries are updated to "dirty"
+    // entries pointing below the memset, so subsequent queries include the
+    // memset.
+    AMemSet =
+      Builder.CreateMemSet(StartPtr, ByteVal, Range.End-Range.Start, Alignment);
+    if (!Range.TheStores.empty())
+      AMemSet->setDebugLoc(Loc);
+
+    DEBUG(dbgs() << "With: " << *AMemSet << '\n');
+
     ++NumMemSetInfer;
   }
 
   return AMemSet;
 }
 
 static unsigned findCommonAlignment(const DataLayout &DL, const StoreInst *SI,
                                      const LoadInst *LI) {
bool MemCpyOptPass::processMemCpyMemCpyDependence(MemCpyInst *M,
   //    memcpy(c <- a)
   // It would be invalid to transform the second memcpy into memcpy(c <- b).
   //
   // TODO: If the code between M and MDep is transparent to the destination "c",
   // then we could still perform the xform by moving M up to the first memcpy.
   //
   // NOTE: This is conservative, it will stop on any read from the source loc,
   // not just the defining memcpy.
-  MemDepResult SourceDep =
-      MD->getPointerDependencyFrom(MemoryLocation::getForSource(MDep), false,
+  MemoryLocation SourceLoc = MemoryLocation::getForSource(MDep);
+  MemDepResult SourceDep = MD->getPointerDependencyFrom(SourceLoc, false,
                                                         M->getIterator(), M->getParent());
+
+  if (SourceDep.isNonLocal()) {
+    SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
+    MD->getNonLocalPointerDependencyFrom(M, SourceLoc, /*isLoad=*/false,
+                                         NonLocalDepResults);
+    if (NonLocalDepResults.size() == 1) {
+      SourceDep = NonLocalDepResults[0].getResult();
+      assert((!SourceDep.getInst() ||
+              LookupDomTree().dominates(SourceDep.getInst(), M)) &&
+             "when memdep returns exactly one result, it should dominate");
+    }
+  }
+
   if (!SourceDep.isClobber() || SourceDep.getInst() != MDep)
     return false;
 
   // If the dest of the second might alias the source of the first, then the
   // source and dest might overlap.  We still want to eliminate the intermediate
   // value, but we have to generate a memmove instead of memcpy.
   bool UseMemMove = false;
   if (!AA.isNoAlias(MemoryLocation::getForDest(M),
if (CallInst *C = dyn_cast<CallInst>(DepInfo.getInst())) {
       }
     }
   }
 
   MemoryLocation SrcLoc = MemoryLocation::getForSource(M);
   MemDepResult SrcDepInfo = MD->getPointerDependencyFrom(
       SrcLoc, true, M->getIterator(), M->getParent());
 
+  if (SrcDepInfo.isNonLocal()) {
+    SmallVector<NonLocalDepResult, 2> NonLocalDepResults;
+    MD->getNonLocalPointerDependencyFrom(M, SrcLoc, /*isLoad=*/true,
+                                         NonLocalDepResults);
+    if (NonLocalDepResults.size() == 1) {
+      SrcDepInfo = NonLocalDepResults[0].getResult();
+      assert((!SrcDepInfo.getInst() ||
+              LookupDomTree().dominates(SrcDepInfo.getInst(), M)) &&
+             "when memdep returns exactly one result, it should dominate");
+    }
+  }
+
   if (SrcDepInfo.isClobber()) {
     if (MemCpyInst *MDep = dyn_cast<MemCpyInst>(SrcDepInfo.getInst()))
       return processMemCpyMemCpyDependence(M, MDep);
   } else if (SrcDepInfo.isDef()) {
     Instruction *I = SrcDepInfo.getInst();
     bool hasUndefContents = false;
 
     if (isa<AllocaInst>(I)) {

llvm/trunk/test/Transforms/MemCpyOpt/memcpy-invoke-memcpy.ll

+; RUN: opt < %s -memcpyopt -S | FileCheck %s
+; Test memcpy-memcpy dependencies across invoke edges.
+
+; Test that memcpyopt works across the non-unwind edge of an invoke.
+
+define hidden void @test_normal(i8* noalias %dst, i8* %src) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %temp = alloca i8, i32 64
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64 64, i32 8, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64 64, i32 8, i1 false)
+  invoke void @invoke_me()
+          to label %try.cont unwind label %lpad
+
+lpad:
+  landingpad { i8*, i32 }
+          catch i8* null
+  ret void
+
+try.cont:
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %temp, i64 64, i32 8, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 64, i32 8, i1 false)
+  ret void
+}
+
+; Test that memcpyopt works across the unwind edge of an invoke.
+
+define hidden void @test_unwind(i8* noalias %dst, i8* %src) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %temp = alloca i8, i32 64
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64 64, i32 8, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64 64, i32 8, i1 false)
+  invoke void @invoke_me()
+          to label %try.cont unwind label %lpad
+
+lpad:
+  landingpad { i8*, i32 }
+          catch i8* null
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %temp, i64 64, i32 8, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 64, i32 8, i1 false)
+  ret void
+
+try.cont:
+  ret void
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1)
+declare i32 @__gxx_personality_v0(...)
+declare void @invoke_me() readnone

llvm/trunk/test/Transforms/MemCpyOpt/merge-into-memset.ll

+; RUN: opt < %s -memcpyopt -S | FileCheck %s
+; Update cached non-local dependence information when merging stores into memset.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+; Don't delete the memcpy in %if.then, even though it depends on an instruction
+; which will be deleted.
+
+; CHECK-LABEL: @foo
+define void @foo(i1 %c, i8* %d, i8* %e, i8* %f) {
+entry:
+  %tmp = alloca [50 x i8], align 8
+  %tmp4 = bitcast [50 x i8]* %tmp to i8*
+  %tmp1 = getelementptr inbounds i8, i8* %tmp4, i64 1
+  call void @llvm.memset.p0i8.i64(i8* nonnull %d, i8 0, i64 10, i32 1, i1 false), !dbg !5
+  store i8 0, i8* %tmp4, align 8, !dbg !5
+; CHECK: call void @llvm.memset.p0i8.i64(i8* nonnull %d, i8 0, i64 10, i32 1, i1 false), !dbg !5
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %tmp1, i8* nonnull %d, i64 10, i32 1, i1 false)
+  br i1 %c, label %if.then, label %exit
+
+if.then:
+; CHECK: if.then:
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %f, i8* nonnull %tmp4, i64 30, i32 8, i1 false)
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %f, i8* nonnull %tmp4, i64 30, i32 8, i1 false)
+  br label %exit
+
+exit:
+  ret void
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)
+declare void @llvm.memset.p0i8.i64(i8*, i8, i64, i32, i1)
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "t.rs", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !DILocation(line: 8, column: 5, scope: !6)
+!6 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 5, type: !7, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!7 = !DISubroutineType(types: !8)
+!8 = !{null}

llvm/trunk/test/Transforms/MemCpyOpt/mixed-sizes.ll

+; RUN: opt < %s -memcpyopt -S | FileCheck %s
+; Handle memcpy-memcpy dependencies of differing sizes correctly.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+; Don't delete the second memcpy, even though there's an earlier
+; memcpy with a larger size from the same address.
+
+; CHECK-LABEL: @foo
+define i32 @foo(i1 %z) {
+entry:
+  %a = alloca [10 x i32]
+  %s = alloca [10 x i32]
+  %0 = bitcast [10 x i32]* %a to i8*
+  %1 = bitcast [10 x i32]* %s to i8*
+  call void @llvm.memset.p0i8.i64(i8* nonnull %1, i8 0, i64 40, i32 16, i1 false)
+  %arrayidx = getelementptr inbounds [10 x i32], [10 x i32]* %a, i64 0, i64 0
+  store i32 1, i32* %arrayidx
+  %scevgep = getelementptr [10 x i32], [10 x i32]* %s, i64 0, i64 1
+  %scevgep7 = bitcast i32* %scevgep to i8*
+  br i1 %z, label %for.body3.lr.ph, label %for.inc7.1
+
+for.body3.lr.ph:                                  ; preds = %entry
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %scevgep7, i64 17179869180, i32 4, i1 false)
+  br label %for.inc7.1
+
+for.inc7.1:
+; CHECK: for.inc7.1:
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %scevgep7, i64 4, i32 4, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %scevgep7, i64 4, i32 4, i1 false)
+  %2 = load i32, i32* %arrayidx
+  ret i32 %2
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)
+declare void @llvm.memset.p0i8.i64(i8*, i8, i64, i32, i1)

llvm/trunk/test/Transforms/MemCpyOpt/nonlocal-memcpy-memcpy.ll

+; RUN: opt < %s -memcpyopt -S | FileCheck %s
+; Make sure memcpy-memcpy dependence is optimized across
+; basic blocks (conditional branches and invokes).
+
+%struct.s = type { i32, i32 }
+
+@s_foo = private unnamed_addr constant %struct.s { i32 1, i32 2 }, align 4
+@s_baz = private unnamed_addr constant %struct.s { i32 1, i32 2 }, align 4
+@i = external constant i8*
+
+declare void @qux()
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1)
+declare void @__cxa_throw(i8*, i8*, i8*)
+declare i32 @__gxx_personality_v0(...)
+declare i8* @__cxa_begin_catch(i8*)
+
+; A simple partial redundancy. Test that the second memcpy is optimized
+; to copy directly from the original source rather than from the temporary.
+
+; CHECK-LABEL: @wobble
+define void @wobble(i8* noalias %dst, i8* %src, i1 %some_condition) {
+bb:
+  %temp = alloca i8, i32 64
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64 64, i32 8, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %temp, i8* nonnull %src, i64 64, i32 8, i1 false)
+  br i1 %some_condition, label %more, label %out
+
+out:
+  call void @qux()
+  unreachable
+
+more:
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %temp, i64 64, i32 8, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 64, i32 8, i1 false)
+  ret void
+}
+
+; A CFG triangle with a partial redundancy targeting an alloca. Test that the
+; memcpy inside the triangle is optimized to copy directly from the original
+; source rather than from the temporary.
+
+; CHECK-LABEL: @foo
+define i32 @foo(i1 %t3) {
+bb:
+  %s = alloca %struct.s, align 4
+  %t = alloca %struct.s, align 4
+  %s1 = bitcast %struct.s* %s to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s1, i8* bitcast (%struct.s* @s_foo to i8*), i64 8, i32 4, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s1, i8* bitcast (%struct.s* @s_foo to i8*), i64 8, i32 4, i1 false)
+  br i1 %t3, label %bb4, label %bb7
+
+bb4:                                              ; preds = %bb
+  %t5 = bitcast %struct.s* %t to i8*
+  %s6 = bitcast %struct.s* %s to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t5, i8* %s6, i64 8, i32 4, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t5, i8* bitcast (%struct.s* @s_foo to i8*), i64 8, i32 4, i1 false)
+  br label %bb7
+
+bb7:                                              ; preds = %bb4, %bb
+  %t8 = getelementptr %struct.s, %struct.s* %t, i32 0, i32 0
+  %t9 = load i32, i32* %t8, align 4
+  %t10 = getelementptr %struct.s, %struct.s* %t, i32 0, i32 1
+  %t11 = load i32, i32* %t10, align 4
+  %t12 = add i32 %t9, %t11
+  ret i32 %t12
+}
+
+; A CFG diamond with an invoke on one side, and a partially redundant memcpy
+; into an alloca on the other. Test that the memcpy inside the diamond is
+; optimized to copy ; directly from the original source rather than from the
+; temporary. This more complex test represents a relatively common usage
+; pattern.
+
+; CHECK-LABEL: @baz
+define i32 @baz(i1 %t5) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+bb:
+  %s = alloca %struct.s, align 4
+  %t = alloca %struct.s, align 4
+  %s3 = bitcast %struct.s* %s to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s3, i8* bitcast (%struct.s* @s_baz to i8*), i64 8, i32 4, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %s3, i8* bitcast (%struct.s* @s_baz to i8*), i64 8, i32 4, i1 false)
+  br i1 %t5, label %bb6, label %bb22
+
+bb6:                                              ; preds = %bb
+  invoke void @__cxa_throw(i8* null, i8* bitcast (i8** @i to i8*), i8* null)
+          to label %bb25 unwind label %bb9
+
+bb9:                                              ; preds = %bb6
+  %t10 = landingpad { i8*, i32 }
+          catch i8* null
+  br label %bb13
+
+bb13:                                             ; preds = %bb9
+  %t15 = call i8* @__cxa_begin_catch(i8* null)
+  br label %bb23
+
+bb22:                                             ; preds = %bb
+  %t23 = bitcast %struct.s* %t to i8*
+  %s24 = bitcast %struct.s* %s to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t23, i8* %s24, i64 8, i32 4, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* %t23, i8* bitcast (%struct.s* @s_baz to i8*), i64 8, i32 4, i1 false)
+  br label %bb23
+
+bb23:                                             ; preds = %bb22, %bb13
+  %t17 = getelementptr inbounds %struct.s, %struct.s* %t, i32 0, i32 0
+  %t18 = load i32, i32* %t17, align 4
+  %t19 = getelementptr inbounds %struct.s, %struct.s* %t, i32 0, i32 1
+  %t20 = load i32, i32* %t19, align 4
+  %t21 = add nsw i32 %t18, %t20
+  ret i32 %t21
+
+bb25:                                             ; preds = %bb6
+  unreachable
+}