commit 9128246d1ef1c01ca9ec1d5606b920b59edb8765
Author: Tom Hughes <tom@compton.nu>
Date:   Wed Jan 24 09:37:48 2018 +0000

    Use panSrcBands when accessing the source data

diff --git a/gdal/alg/gdalwarpoperation.cpp b/gdal/alg/gdalwarpoperation.cpp
index b652506623..791ca67db9 100644
--- a/gdal/alg/gdalwarpoperation.cpp
+++ b/gdal/alg/gdalwarpoperation.cpp
@@ -1776,7 +1776,7 @@ CPLErr GDALWarpOperation::WarpRegionToBuffer(
         if( psOptions->nBandCount == 1 )
         {
             // Particular case to simplify the stack a bit.
-            eErr = poSrcDS->GetRasterBand(psOptions->panDstBands[0])->RasterIO(
+            eErr = poSrcDS->GetRasterBand(psOptions->panSrcBands[0])->RasterIO(
                                   GF_Read,
                                   nSrcXOff, nSrcYOff, nSrcXSize, nSrcYSize,
                                   oWK.papabySrcImage[0], nSrcXSize, nSrcYSize,