Commit 40557b23015d2f8b576420231b8dd1f39f2ceed8
2020-11-06T18:51:55
Build: Fix test failures w/ Arm Neon SIMD exts Regression caused by a46c111d9f3642f0ef3819e7298846ccc61869e0 Because of 7723d7f7d0aa40349d5bdd1fbe4f8631fd5a2b57, which was introduced in libjpeg-turbo 1.5.1 in response to #81, merged upsampling/ color conversion is disabled on platforms that have SIMD-accelerated YCbCr -> RGB color conversion but not SIMD-accelerated merged upsampling/color conversion. This was intended to improve performance with the Neon SIMD extensions, since those are the only SIMD extensions for which those circumstances apply. Under normal circumstances, the separate "plain" (non-fancy) upsampling and color conversion routines will produce bitwise-identical output to the merged upsampling/color conversion routines, but that is not the case when skipping scanlines starting at an odd-numbered scanline. The modified test introduced in a46c111d9f3642f0ef3819e7298846ccc61869e0 does precisely that in order to validate the fixes introduced in 9120a247436e84c0b4eea828cb11e8f665fcde30 and a46c111d9f3642f0ef3819e7298846ccc61869e0. Because of 7723d7f7d0aa40349d5bdd1fbe4f8631fd5a2b57, the segfault fixed in 9120a247436e84c0b4eea828cb11e8f665fcde30 and a46c111d9f3642f0ef3819e7298846ccc61869e0 didn't affect the Neon SIMD extensions, so this commit effectively reverts the test modifications in a46c111d9f3642f0ef3819e7298846ccc61869e0 when using those SIMD extensions. We can get rid of this hack, as well as 7723d7f7d0aa40349d5bdd1fbe4f8631fd5a2b57, once a Neon implementation of merged upsampling/color conversion is available.