[llvm-commits] [llvm] r158951 - in /llvm/trunk: lib/Transforms/InstCombine/InstCombineCalls.cpp test/Transforms/InstCombine/invoke.ll

[Duncan Sands]

Hi Nuno,

> instcombine:  disable optimization of 'invoke null/undef'. I'll move this functionality to SimplifyCFG (since we cannot make changes to the CFG here).
> Fixes the crashes with the attached test case

can you just set "nounwind" on the invoke?  (Not sure if that is possible -
maybe for an invoke it can only be done on the callee?).  Then some other
pass will magically take care of it.

Ciao, Duncan.

>
> Added:
>      llvm/trunk/test/Transforms/InstCombine/invoke.ll
> Modified:
>      llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
>
> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=158951&r1=158950&r2=158951&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp Thu Jun 21 18:52:14 2012
> @@ -917,24 +917,24 @@
>       }
>
>     if (isa<ConstantPointerNull>(Callee) || isa<UndefValue>(Callee)) {
> -    // This instruction is not reachable, just remove it.  We insert a store to
> -    // undef so that we know that this code is not reachable, despite the fact
> -    // that we can't modify the CFG here.
> -    new StoreInst(ConstantInt::getTrue(Callee->getContext()),
> -               UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
> -                  CS.getInstruction());
> -
>       // If CS does not return void then replaceAllUsesWith undef.
>       // This allows ValueHandlers and custom metadata to adjust itself.
>       if (!CS.getInstruction()->getType()->isVoidTy())
>         ReplaceInstUsesWith(*CS.getInstruction(),
>                             UndefValue::get(CS.getInstruction()->getType()));
>
> -    if (InvokeInst *II = dyn_cast<InvokeInst>(CS.getInstruction())) {
> -      // Don't break the CFG, insert a dummy cond branch.
> -      BranchInst::Create(II->getNormalDest(), II->getUnwindDest(),
> -                         ConstantInt::getTrue(Callee->getContext()), II);
> +    if (isa<InvokeInst>(CS.getInstruction())) {
> +      // Can't remove an invoke because we cannot change the CFG.
> +      return 0;
>       }
> +
> +    // This instruction is not reachable, just remove it.  We insert a store to
> +    // undef so that we know that this code is not reachable, despite the fact
> +    // that we can't modify the CFG here.
> +    new StoreInst(ConstantInt::getTrue(Callee->getContext()),
> +                  UndefValue::get(Type::getInt1PtrTy(Callee->getContext())),
> +                  CS.getInstruction());
> +
>       return EraseInstFromFunction(*CS.getInstruction());
>     }
>
>
> Added: llvm/trunk/test/Transforms/InstCombine/invoke.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/invoke.ll?rev=158951&view=auto
> ==============================================================================
> --- llvm/trunk/test/Transforms/InstCombine/invoke.ll (added)
> +++ llvm/trunk/test/Transforms/InstCombine/invoke.ll Thu Jun 21 18:52:14 2012
> @@ -0,0 +1,47 @@
> +; RUN: opt<  %s -instcombine -S | FileCheck %s
> +target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
> +
> +declare i32 @__gxx_personality_v0(...)
> +declare void @__cxa_call_unexpected(i8*)
> +declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readonly
> +
> +
> +; CHECK: @f1
> +define i64 @f1() nounwind uwtable ssp {
> +entry:
> +; CHECK: nvoke noalias i8* undef()
> +  %call = invoke noalias i8* undef()
> +          to label %invoke.cont unwind label %lpad
> +
> +invoke.cont:
> +; CHECK: ret i64 0
> +  %0 = tail call i64 @llvm.objectsize.i64(i8* %call, i1 false)
> +  ret i64 %0
> +
> +lpad:
> +  %1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
> +          filter [0 x i8*] zeroinitializer
> +  %2 = extractvalue { i8*, i32 } %1, 0
> +  tail call void @__cxa_call_unexpected(i8* %2) noreturn nounwind
> +  unreachable
> +}
> +
> +; CHECK: @f2
> +define i64 @f2() nounwind uwtable ssp {
> +entry:
> +; CHECK: nvoke noalias i8* null()
> +  %call = invoke noalias i8* null()
> +          to label %invoke.cont unwind label %lpad
> +
> +invoke.cont:
> +; CHECK: ret i64 0
> +  %0 = tail call i64 @llvm.objectsize.i64(i8* %call, i1 false)
> +  ret i64 %0
> +
> +lpad:
> +  %1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
> +          filter [0 x i8*] zeroinitializer
> +  %2 = extractvalue { i8*, i32 } %1, 0
> +  tail call void @__cxa_call_unexpected(i8* %2) noreturn nounwind
> +  unreachable
> +}
>
>
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