| ; RUN: opt < %s -early-cse-memssa -earlycse-debug-hash -verify-memoryssa -disable-output |
| ; REQUIRES: asserts |
| |
| target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" |
| target triple = "x86_64-unknown-linux-gnu" |
| |
| ; Tests below highlight scenarios where EarlyCSE does not preserve MemorySSA |
| ; optimized accesses. Current MemorySSA verify will accept these. |
| |
| ; Test 1: |
| ; AA cannot tell here that the last load does not alias the only store. |
| ; The first two loads are a common expression, EarlyCSE removes the second one, |
| ; and then AA can see that the last load is a Use(LoE). Hence not optimized as |
| ; it claims. Note that if we replace the GEP indices 2 and 1, AA sees NoAlias |
| ; for the last load, before CSE-ing the first 2 loads. |
| %struct.ImageParameters = type { i32, i32, i32 } |
| @img = external global %struct.ImageParameters*, align 8 |
| define void @test1_macroblock() { |
| entry: |
| ; MemoryUse(LoE) |
| %0 = load %struct.ImageParameters*, %struct.ImageParameters** @img, align 8 |
| |
| %Pos_2 = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %0, i64 0, i32 2 |
| ; 1 = MemoryDef(LoE) |
| store i32 undef, i32* %Pos_2, align 8 |
| |
| ; MemoryUse(LoE) |
| %1 = load %struct.ImageParameters*, %struct.ImageParameters** @img, align 8 |
| |
| %Pos_1 = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %1, i64 0, i32 1 |
| ; MemoryUse(1) MayAlias |
| %2 = load i32, i32* %Pos_1, align 4 |
| unreachable |
| } |
| |
| ; Test 2: |
| ; EarlyCSE simplifies %string to undef. Def and Use used to be MustAlias, with |
| ; undef they are NoAlias. The Use can be optimized further to LoE. We can |
| ; de-optimize uses of replaced instructions, but in general this is not enough |
| ; (see next tests). |
| %struct.TermS = type { i32, i32, i32, i32, i32, i8* } |
| define fastcc void @test2_term_string() { |
| entry: |
| %string = getelementptr inbounds %struct.TermS, %struct.TermS* undef, i64 0, i32 5 |
| ; 1 = MemoryDef(LoE) |
| store i8* undef, i8** %string, align 8 |
| ; MemoryUse(1) MustAlias |
| %0 = load i8*, i8** %string, align 8 |
| unreachable |
| } |
| |
| ; Test 3: |
| ; EarlyCSE simplifies %0 to undef. So the second Def now stores to undef. |
| ; We now find the second load (Use(2) can be optimized further to LoE) |
| ; When replacing instructions, we can deoptimize all uses of the replaced |
| ; instruction and all uses of transitive accesses. However this does not stop |
| ; MemorySSA from being tripped by AA (see test4). |
| %struct.Grammar = type { i8*, i8*, %struct.anon } |
| %struct.anon = type { i32, i32, %struct.Term**, [3 x %struct.Term*] } |
| %struct.Term = type { i32 } |
| |
| define fastcc void @test3_term_string(%struct.Grammar* %g) { |
| entry: |
| ; 1 = MemoryDef(LoE) |
| store i8* undef, i8** undef, align 8 |
| ; MemoryUse(LoE) |
| %0 = load i8*, i8** undef, align 8 |
| %arrayidx = getelementptr inbounds i8, i8* %0, i64 undef |
| ; 2 = MemoryDef(1) |
| store i8 0, i8* %arrayidx, align 1 |
| %v = getelementptr inbounds %struct.Grammar, %struct.Grammar* %g, i64 0, i32 2, i32 2 |
| ; MemoryUse(2) MayAlias |
| %1 = load %struct.Term**, %struct.Term*** %v, align 8 |
| unreachable |
| } |
| |
| ; Test 4: |
| ; Removing dead/unused instructions in if.then274 makes AA smarter. Before |
| ; removal, it finds %4 MayAlias the store above. After removal this can be |
| ; optimized to LoE. Hence after EarlyCSE, there is an access who claims is |
| ; optimized and it can be optimized further. |
| |
| ; We can't escape such cases in general when relying on Alias Analysis. |
| ; The only fail-safe way to actually preserve MemorySSA when removing or |
| ; replacing instructions (i.e. get the *same* MemorySSA as if it was computed |
| ; for the updated IR) is to recompute it from scratch. What we get now is still |
| ; a correct update, but with accesses that claim to be optimized and can be |
| ; optimized further if we were to re-run MemorySSA on the IR. |
| %struct.gnode.0.1.3.6.9.18.20.79 = type { i32, i32, i32, i32, i32, i32, i32, %struct.gnode.0.1.3.6.9.18.20.79* } |
| @gnodeArray = external global %struct.gnode.0.1.3.6.9.18.20.79**, align 8 |
| |
| define void @test4_shortest() { |
| entry: |
| %exl.i = alloca [5 x i32], align 16 |
| br i1 undef, label %if.then274, label %for.cond404 |
| |
| if.then274: ; preds = %if.end256 |
| %0 = bitcast [5 x i32]* %exl.i to i8* |
| %arrayidx.i = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 1 |
| %arrayidx1.i = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 2 |
| %arrayidx2.i = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 3 |
| %arrayidx3.i = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 4 |
| %1 = bitcast [5 x i32]* %exl.i to i8* |
| %arrayidx.i1034 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 1 |
| %arrayidx1.i1035 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 2 |
| %arrayidx2.i1036 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 3 |
| %arrayidx3.i1037 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 4 |
| unreachable |
| |
| for.cond404: ; preds = %if.end256 |
| %2 = bitcast [5 x i32]* %exl.i to i8* |
| %arrayidx.i960 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 1 |
| %arrayidx1.i961 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 2 |
| %arrayidx2.i962 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 3 |
| ; 1 = MemoryDef(LoE) |
| store i32 undef, i32* %arrayidx2.i962, align 4 |
| %arrayidx3.i963 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 4 |
| |
| ; MemoryUse(LoE) |
| %3 = load %struct.gnode.0.1.3.6.9.18.20.79**, %struct.gnode.0.1.3.6.9.18.20.79*** @gnodeArray, align 8 |
| %arrayidx6.i968 = getelementptr inbounds %struct.gnode.0.1.3.6.9.18.20.79*, %struct.gnode.0.1.3.6.9.18.20.79** %3, i64 undef |
| ; MemoryUse(1) MayAlias |
| %4 = load %struct.gnode.0.1.3.6.9.18.20.79*, %struct.gnode.0.1.3.6.9.18.20.79** %arrayidx6.i968, align 8 |
| br i1 undef, label %for.cond26.preheader.i974, label %if.then20.for.body_crit_edge.i999 |
| |
| for.cond26.preheader.i974: ; preds = %if.then20.i996 |
| %5 = bitcast [5 x i32]* %exl.i to i8* |
| %arrayidx.i924 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 1 |
| %arrayidx1.i925 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 2 |
| %arrayidx2.i926 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 3 |
| %arrayidx3.i927 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 4 |
| unreachable |
| |
| if.then20.for.body_crit_edge.i999: ; preds = %if.then20.i996 |
| %arrayidx9.phi.trans.insert.i997 = getelementptr inbounds [5 x i32], [5 x i32]* %exl.i, i64 0, i64 undef |
| unreachable |
| } |