diff options
| -rw-r--r-- | lib/VMCore/ConstantFold.cpp | 11 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2007-09-10-AliasConstFold.ll | 13 |
2 files changed, 20 insertions, 4 deletions
diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index 5686a0e35f..4dc1340f90 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -23,6 +23,7 @@ #include "llvm/Instructions.h" #include "llvm/DerivedTypes.h" #include "llvm/Function.h" +#include "llvm/GlobalAlias.h" #include "llvm/ADT/SmallVector.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/GetElementPtrTypeIterator.h" @@ -951,12 +952,14 @@ static ICmpInst::Predicate evaluateICmpRelation(const Constant *V1, // Now we know that the RHS is a GlobalValue or simple constant, // which (since the types must match) means that it's a ConstantPointerNull. if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) { - if (!CPR1->hasExternalWeakLinkage() || !CPR2->hasExternalWeakLinkage()) - return ICmpInst::ICMP_NE; + // Don't try to decide equality of aliases. + if (!isa<GlobalAlias>(CPR1) && !isa<GlobalAlias>(CPR2)) + if (!CPR1->hasExternalWeakLinkage() || !CPR2->hasExternalWeakLinkage()) + return ICmpInst::ICMP_NE; } else { - // GlobalVals can never be null. assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!"); - if (!CPR1->hasExternalWeakLinkage()) + // GlobalVals can never be null. Don't try to evaluate aliases. + if (!CPR1->hasExternalWeakLinkage() && !isa<GlobalAlias>(CPR1)) return ICmpInst::ICMP_NE; } } else { diff --git a/test/Transforms/InstCombine/2007-09-10-AliasConstFold.ll b/test/Transforms/InstCombine/2007-09-10-AliasConstFold.ll new file mode 100644 index 0000000000..2dcb43926b --- /dev/null +++ b/test/Transforms/InstCombine/2007-09-10-AliasConstFold.ll @@ -0,0 +1,13 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep icmp +; PR1646 + +@__gthrw_pthread_cancel = alias weak i32 (i32)* @pthread_cancel ; <i32 (i32)*> [#uses=1] +@__gthread_active_ptr.5335 = internal constant i8* bitcast (i32 (i32)* @__gthrw_pthread_cancel to i8*) ; <i8**> [#uses=1] +declare extern_weak i32 @pthread_cancel(i32) + +define i1 @__gthread_active_p() { +entry: + %tmp1 = load i8** @__gthread_active_ptr.5335, align 4 ; <i8*> [#uses=1] + %tmp2 = icmp ne i8* %tmp1, null ; <i1> [#uses=1] + ret i1 %tmp2 +} |