diff options
| -rw-r--r-- | llvm/lib/Analysis/BasicAliasAnalysis.cpp | 6 | ||||
| -rw-r--r-- | llvm/test/Analysis/BasicAA/2008-04-15-Byval.ll | 18 |
2 files changed, 22 insertions, 2 deletions
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp index b696a800cf6..ad462076385 100644 --- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp +++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp @@ -273,8 +273,10 @@ BasicAliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) { // If this is a tail call and P points to a stack location, we know that // the tail call cannot access or modify the local stack. - if (isa<AllocaInst>(Object) || - (isa<Argument>(Object) && cast<Argument>(Object)->hasByValAttr())) + // We cannot exclude byval arguments here; these belong to the caller of + // the current function not to the current function, and a tail callee + // may reference them. + if (isa<AllocaInst>(Object)) if (CallInst *CI = dyn_cast<CallInst>(CS.getInstruction())) if (CI->isTailCall()) return NoModRef; diff --git a/llvm/test/Analysis/BasicAA/2008-04-15-Byval.ll b/llvm/test/Analysis/BasicAA/2008-04-15-Byval.ll new file mode 100644 index 00000000000..ee16909977d --- /dev/null +++ b/llvm/test/Analysis/BasicAA/2008-04-15-Byval.ll @@ -0,0 +1,18 @@ +; RUN: llvm-as < %s | opt -std-compile-opts | llvm-dis | grep store +; ModuleID = 'small2.c' +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-darwin8" + %struct.x = type { [4 x i32] } + +define void @foo(%struct.x* byval align 4 %X) nounwind { +entry: + %tmp = getelementptr %struct.x* %X, i32 0, i32 0 ; <[4 x i32]*> [#uses=1] + %tmp1 = getelementptr [4 x i32]* %tmp, i32 0, i32 3 ; <i32*> [#uses=1] + store i32 2, i32* %tmp1, align 4 + %tmp2 = call i32 (...)* @bar( %struct.x* byval align 4 %X ) nounwind ; <i32> [#uses=0] + br label %return +return: ; preds = %entry + ret void +} + +declare i32 @bar(...) |
