diff options
| -rw-r--r-- | lib/Transforms/IPO/DeadArgumentElimination.cpp | 59 | ||||
| -rw-r--r-- | test/Transforms/DeadArgElim/multdeadretval.ll | 15 |
2 files changed, 35 insertions, 39 deletions
diff --git a/lib/Transforms/IPO/DeadArgumentElimination.cpp b/lib/Transforms/IPO/DeadArgumentElimination.cpp index 34e73295d7..9d29c8366e 100644 --- a/lib/Transforms/IPO/DeadArgumentElimination.cpp +++ b/lib/Transforms/IPO/DeadArgumentElimination.cpp @@ -796,45 +796,28 @@ bool DAE::RemoveDeadStuffFromFunction(Function *F) { } else { assert(STy && "Return type changed, but not into a void. The old " "return type must have been a struct!"); - // The original return value was a struct, update all uses (which are - // all extractvalue instructions, or uses that are unused themselves). - for (Value::use_iterator I = Call->use_begin(), E = Call->use_end(); - I != E;) { - if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(*I)) { - // Increment now, since we're about to throw away this use. - ++I; - assert(EV->hasIndices() && "Return value used by extractvalue without" - "indices?"); - unsigned Idx = *EV->idx_begin(); - if (NewRetIdxs[Idx] != -1) { - if (RetTypes.size() > 1) { - // We're still returning a struct, create a new extractvalue - // instruction with the first index updated - std::vector<unsigned> NewIdxs(EV->idx_begin(), EV->idx_end()); - NewIdxs[0] = NewRetIdxs[Idx]; - Value *NEV = ExtractValueInst::Create(New, NewIdxs.begin(), - NewIdxs.end(), "retval", - EV); - EV->replaceAllUsesWith(NEV); - EV->eraseFromParent(); - } else { - // We are now only returning a simple value, remove the - // extractvalue. - EV->replaceAllUsesWith(New); - EV->eraseFromParent(); - } - } else { - // Value unused, replace uses by null for now, they will get removed - // later on. - EV->replaceAllUsesWith(Constant::getNullValue(EV->getType())); - EV->eraseFromParent(); - } - } else { - // Not an extractvalue, so this use will become dead soon. Just - // replace it with null. - I.getUse().set(Constant::getNullValue(I.getUse().get()->getType())); + // We used to return a struct. Instead of doing smart stuff with all the + // uses of this struct, we will just rebuild it using + // extract/insertvalue chaining and let instcombine clean that up. + // + // Start out building up our return value from undef + Value *RetVal = llvm::UndefValue::get(RetTy); + for (unsigned i = 0; i != PartialRetVals; ++i) + if (NewRetIdxs[i] != -1) { + Value *V; + if (RetTypes.size() > 1) + // We are still returning a struct, so extract the value from our + // return value + V = ExtractValueInst::Create(New, NewRetIdxs[i], "newret", Call); + else + // We are now returning a single element, so just insert that + V = New; + // Insert the value at the old position + RetVal = InsertValueInst::Create(RetVal, V, i, "oldret", Call); } - } + // Now, replace all uses of the old call instruction with the return + // struct we built + Call->replaceAllUsesWith(RetVal); New->takeName(Call); } } diff --git a/test/Transforms/DeadArgElim/multdeadretval.ll b/test/Transforms/DeadArgElim/multdeadretval.ll index f60fd0fc39..6e0474a6f8 100644 --- a/test/Transforms/DeadArgElim/multdeadretval.ll +++ b/test/Transforms/DeadArgElim/multdeadretval.ll @@ -38,6 +38,14 @@ define internal {i32, i32, i16} @test5() { ret {i32, i32, i16} %C } +; Nested return values +define internal {{i32}, {i16, i16}} @test6() { + %A = insertvalue {{i32}, {i16, i16}} undef, i32 1, 0, 0 + %B = insertvalue {{i32}, {i16, i16}} %A, i16 2, 1, 0 + %C = insertvalue {{i32}, {i16, i16}} %B, i16 3, 1, 1 + ret {{i32}, {i16, i16}} %C +} + define i32 @main() { %ret = call {i32, i16} @test2() ; <i32> [#uses=1] %LIVE = extractvalue {i32, i16} %ret, 0 @@ -51,5 +59,10 @@ define i32 @main() { %DEAD2 = extractvalue { i32, i32, i16} %ret1, 2 %V = add i32 %LIVE3, %LIVE4 %W = add i32 %Z, %V - ret i32 %W + %ret2 = call { { i32 }, { i16, i16 } } @test6 () + %LIVE5 = extractvalue { { i32 }, { i16, i16 } } %ret2, 0, 0 + %DEAD3 = extractvalue { { i32 }, { i16, i16 } } %ret2, 1, 0 + %DEAD4 = extractvalue { { i32 }, { i16, i16 } } %ret2, 1, 1 + %Q = add i32 %W, %LIVE5 + ret i32 %Q } |