diff options
| -rw-r--r-- | llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp | 25 | ||||
| -rw-r--r-- | llvm/test/Transforms/SimplifyCFG/2009-07-13-no-delete-asm.ll | 11 |
2 files changed, 8 insertions, 28 deletions
diff --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp index 155d5d81e30..f6cffdd0ef4 100644 --- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp +++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp @@ -109,8 +109,6 @@ static bool MarkAliveBlocks(BasicBlock *BB, if (!Reachable.insert(BB)) continue; - bool AsmFound = false; - StoreInst *UndefStore = 0; // Do a quick scan of the basic block, turning any obviously unreachable // instructions into LLVM unreachable insts. The instruction combining pass // canonicalizes unreachable insts into stores to null or undef. @@ -127,27 +125,20 @@ static bool MarkAliveBlocks(BasicBlock *BB, } break; } - if (isa<InlineAsm>(CI->getOperand(0))) - AsmFound = true; } if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) { Value *Ptr = SI->getOperand(1); - - if ((isa<UndefValue>(Ptr) || - (isa<ConstantPointerNull>(Ptr) && - cast<PointerType>(Ptr->getType())->getAddressSpace() == 0)) && - !UndefStore) - UndefStore = SI; + + if (isa<UndefValue>(Ptr) || + (isa<ConstantPointerNull>(Ptr) && + cast<PointerType>(Ptr->getType())->getAddressSpace() == 0)) { + ChangeToUnreachable(SI, Context); + Changed = true; + break; + } } } - // We can't delete asm's just because their inputs are undefined; - // xor R, R is a common idiom for zeroing a register, for example. - // Assume user knows what he is doing. - if (UndefStore && !AsmFound) { - ChangeToUnreachable(UndefStore, Context); - Changed = true; - } // Turn invokes that call 'nounwind' functions into ordinary calls. if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator())) diff --git a/llvm/test/Transforms/SimplifyCFG/2009-07-13-no-delete-asm.ll b/llvm/test/Transforms/SimplifyCFG/2009-07-13-no-delete-asm.ll deleted file mode 100644 index 4664ee0348c..00000000000 --- a/llvm/test/Transforms/SimplifyCFG/2009-07-13-no-delete-asm.ll +++ /dev/null @@ -1,11 +0,0 @@ -; RUN: llvm-as < %s | opt -simplifycfg | llvm-dis | grep xor -; ModuleID = '<stdin>' -target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" -target triple = "i386-apple-darwin9.6" - -define void @bar() nounwind { -entry: - store i16 undef, i16* null - %asmtmp = call i32 asm sideeffect "xor $0, $0", "=={bx},rm,~{dirflag},~{fpsr},~{flags},~{memory}"(i16 undef) nounwind ; <i32> [#uses=0] - ret void -} |
