How do I make gdalwarp set target extents to -180 -90 180 90?

I'm using gdalwarp with the -te option and it doesn't appear to be working like I expected.

I'm running a command like:

gdalwarp -of GTiff -te -180 -90 180 90 -tr 0.1 0.1 -t_srs EPSG:4326 input.tif output.tif

or

gdalwarp -of GTiff -te -180.0 -90.0 180.0 90.0 -tr 0.1 0.1 -t_srs EPSG:4326 input.tif output.tif

But when I run gdalinfo after executing gdalwarp I get this:

Upper Left  (-180.0000000,  90.0000000) (180d 0'0.00"W, 90d 0'0.00"N)
Lower Left  (-180.0000000, -89.9903092) (180d 0'0.00"W, 89d59'25.11"S)
Upper Right ( 179.9806183,  90.0000000) (179d58'50.23"E, 90d 0'0.00"N)
Lower Right ( 179.9806183, -89.9903092) (179d58'50.23"E, 89d59'25.11"S)
Center      (  -0.0096908,   0.0048454) (  0d 0'34.89"W,  0d 0'17.44"N)

How can I create a geotiff where the extents with the following values?

Upper Left  (-180.0000000,  90.0000000) (180d 0'0.00"W, 90d 0'0.00"N)
Lower Left  (-180.0000000, -90.0000000) (180d 0'0.00"W, 90d 0'0.00"S)
Upper Right ( 180.0000000,  90.0000000) (180d 0'0.00"E, 90d 0'0.00"N)
Lower Right ( 180.0000000, -90.0000000) (180d 0'0.00"E, 90d 0'0.00"S)
Center      (   0.0000000,   0.0000000) (  0d 0'0.00"W,  0d 0'0.00"N)