Revert 75571; I'm convinced this isn't the right thing to do.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75642 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 155d5d8..f6cffdd 100644
--- a/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -109,8 +109,6 @@
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 @@
}
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()))