diff options
| -rw-r--r-- | lib/Transforms/Scalar/SCCP.cpp | 6 | ||||
| -rw-r--r-- | test/Transforms/SCCP/2008-05-23-UndefCallFold.ll | 14 |
2 files changed, 20 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp index 79cda33f79..da715acd29 100644 --- a/lib/Transforms/Scalar/SCCP.cpp +++ b/lib/Transforms/Scalar/SCCP.cpp @@ -1370,6 +1370,12 @@ bool SCCPSolver::ResolvedUndefsIn(Function &F) { else markOverdefined(LV, I); return true; + case Instruction::Call: + // If a call has an undef result, it is because it is constant foldable + // but one of the inputs was undef. Just force the result to + // overdefined. + markOverdefined(LV, I); + return true; } } diff --git a/test/Transforms/SCCP/2008-05-23-UndefCallFold.ll b/test/Transforms/SCCP/2008-05-23-UndefCallFold.ll new file mode 100644 index 0000000000..f85a36260e --- /dev/null +++ b/test/Transforms/SCCP/2008-05-23-UndefCallFold.ll @@ -0,0 +1,14 @@ +; RUN: llvm-as < %s | opt -sccp | llvm-dis | not grep {ret i32 undef} +; PR2358 +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 = "i686-pc-linux-gnu" + +define i32 @x(i32 %b) { +entry: + %val = call i32 @llvm.cttz.i32(i32 undef) + ret i32 %val +} + +declare i32 @llvm.cttz.i32(i32) + |