diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp index 02e6b72d3af..196a847fc0e 100644 --- a/lib/Transforms/Scalar/SCCP.cpp +++ b/lib/Transforms/Scalar/SCCP.cpp @@ -1433,15 +1433,25 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) { if (I->getType()->isVoidTy()) continue; if (StructType *STy = dyn_cast(I->getType())) { - // Only a few things that can be structs matter for undef. Just send - // all their results to overdefined. We could be more precise than this - // but it isn't worth bothering. - if (!isa(I) && !isa(I)) { - for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { - LatticeVal &LV = getStructValueState(I, i); - if (LV.isUndefined()) - markOverdefined(LV, I); - } + // Only a few things that can be structs matter for undef. + + // Tracked calls must never be marked overdefined in ResolvedUndefsIn. + if (CallSite CS = CallSite(I)) + if (Function *F = CS.getCalledFunction()) + if (MRVFunctionsTracked.count(F)) + continue; + + // extractvalue and insertvalue don't need to be marked; they are + // tracked as precisely as their operands. + if (isa(I) || isa(I)) + continue; + + // Send the results of everything else to overdefined. We could be + // more precise than this but it isn't worth bothering. + for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) { + LatticeVal &LV = getStructValueState(I, i); + if (LV.isUndefined()) + markOverdefined(LV, I); } continue; } @@ -1594,6 +1604,22 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) { break; markOverdefined(I); return true; + case Instruction::Call: + case Instruction::Invoke: { + // There are two reasons a call can have an undef result + // 1. It could be tracked. + // 2. It could be constant-foldable. + // Because of the way we solve return values, tracked calls must + // never be marked overdefined in ResolvedUndefsIn. + if (Function *F = CallSite(I).getCalledFunction()) + if (TrackedRetVals.count(F)) + break; + + // If the call is constant-foldable, we mark it overdefined because + // we do not know what return values are valid. + markOverdefined(I); + return true; + } default: // If we don't know what should happen here, conservatively mark it // overdefined. diff --git a/test/Transforms/SCCP/ipsccp-basic.ll b/test/Transforms/SCCP/ipsccp-basic.ll index 6ccfd982343..8340f0c1e12 100644 --- a/test/Transforms/SCCP/ipsccp-basic.ll +++ b/test/Transforms/SCCP/ipsccp-basic.ll @@ -209,3 +209,21 @@ entry: } declare i32 @__gxx_personality_v0(...) + +;;======================== test10 + +define i32 @test10a() nounwind { +entry: + %call = call i32 @test10b(i32 undef) + ret i32 %call +; CHECK: define i32 @test10a +; CHECK: ret i32 0 +} + +define internal i32 @test10b(i32 %x) nounwind { +entry: + %r = and i32 %x, 1 + ret i32 %r +; CHECK: define internal i32 @test10b +; CHECK: ret i32 undef +}