From 65277a2bc03d7de72d97d35e496c01458f3951a5 Mon Sep 17 00:00:00 2001 From: Tim Northover Date: Sun, 15 Jun 2014 09:27:20 +0000 Subject: LegalizeDAG: make sure cast is unsigned before using FP_TO_UINT. It's valid to use FP_TO_SINT when asking for a smaller type (e.g. all "unsigned int16" values fit into a "signed int32"), but the reverse isn't true. Unfortunately, I'm not actually aware of any architecture with asymmetric FP_TO_SINT and FP_TO_UINT handling and the logic happens to work in the symmetric case, so I can't actually write a test for this. llvm-svn: 210986 --- llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp index c76a52abe69..48eb86c49c3 100644 --- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp @@ -2650,12 +2650,15 @@ SDValue SelectionDAGLegalize::PromoteLegalFP_TO_INT(SDValue LegalOp, NewOutTy = (MVT::SimpleValueType)(NewOutTy.getSimpleVT().SimpleTy+1); assert(NewOutTy.isInteger() && "Ran out of possibilities!"); + // A larger signed type can hold all unsigned values of the requested type, + // so using FP_TO_SINT is valid if (TLI.isOperationLegalOrCustom(ISD::FP_TO_SINT, NewOutTy)) { OpToUse = ISD::FP_TO_SINT; break; } - if (TLI.isOperationLegalOrCustom(ISD::FP_TO_UINT, NewOutTy)) { + // However, if the value may be < 0.0, we *must* use some FP_TO_SINT. + if (!isSigned && TLI.isOperationLegalOrCustom(ISD::FP_TO_UINT, NewOutTy)) { OpToUse = ISD::FP_TO_UINT; break; } -- cgit v1.2.3