From 3617a1a7881f2cc7a1527dda28e48462b791c94f Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Mon, 15 Jul 2019 17:56:57 +0000 Subject: [PATCH] [X86] Return UNDEF from LowerScalarImmediateShift when the shift amount is out of range. I think we only turn out of range shiftss to undef when all elements are out of range or the shift amount is a splat out of range. I'm not sure which, I didn't check. During lowering we can split a shift where some elements are out of range into multiple shifts. This can create a new shift with a splat shift amount that is out of range. This patch returns undef for this case. Fixes PR42615. Differential Revision: https://reviews.llvm.org/D64699 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366096 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86ISelLowering.cpp | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index c5bf3dcac45..47389f2df32 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -25033,8 +25033,11 @@ static SDValue LowerScalarImmediateShift(SDValue Op, SelectionDAG &DAG, APInt APIntShiftAmt; if (!isConstantSplat(Amt, APIntShiftAmt)) return SDValue(); - assert(APIntShiftAmt.ult(VT.getScalarSizeInBits()) && - "Out of range shift amount"); + + // If the shift amount is out of range, return undef. + if (APIntShiftAmt.uge(VT.getScalarSizeInBits())) + return DAG.getUNDEF(VT); + uint64_t ShiftAmt = APIntShiftAmt.getZExtValue(); if (SupportedVectorShiftWithImm(VT, Subtarget, Op.getOpcode())) -- 2.40.0