Change Details

This patch enhances the MVE-VPT block insertion pass by allowing it to remove VPNOT instructions to place the predicated instructions in an "else" block, resulting in more compact code. Previously, this pass generated this kind of assembly: ``` vldrw.u32 q1, [r5] vpt.s32 ge, q1, r2 ; Added by MVE-VPT block insertion pass vcmpt.s32 le, q1, r3 vpnot vpst ; Added by MVE-VPT block insertion pass vstrwt.32 q0, [r5], #16 ``` Now, when the VPNOT's result (stored in VPR) is not needed, and when the above block has enough room, it'll generate this instead: ``` vldrw.u32 q1, [r5] vpte.s32 ge, q1, r2 ; Added by MVE-VPT block insertion pass vcmpt.s32 le, q1, r3 vstrwe.32 q0, [r5], #16 ``` This is much shorter and should be more efficient, and the pass will only remove the VPNOT when VPR is used+killed by one instruction or when VPR is written to in its block. This should be enough to avoid losing the result of a VPNOT if it's needed, however I'm open to suggestions as I don't actually know if it's good enough. The patch also contains some minor formatting changes, as I ran clang-format on the file to format my code, and it changed old code as well, but I believe it's for the better. I can always revert if you want.

This patch adds a feature to the MVE VPT block insertion patch: It can now remove VPNOT instructions in some circumstances in order to place the instructions predicated by the VPNOT in an else block instead; This results in more compact code. For example, this pass used to generate this kind of assembly: ``` vldrw.u32 q1, [r5] vpt.s32 ge, q1, r2 ; Added by MVE-VPT block insertion pass vcmpt.s32 le, q1, r3 vpnot vpst ; Added by MVE-VPT block insertion pass vstrwt.32 q0, [r5], #16 ``` Now, when the VPNOT's result (stored in VPR) is not needed, and when the above block has enough room, it'll generate this instead: ``` vldrw.u32 q1, [r5] vpte.s32 ge, q1, r2 ; Added by MVE-VPT block insertion pass - Notice the "te" instead of "t" vcmpt.s32 le, q1, r3 vstrwe.32 q0, [r5], #16 ; "t" changed to "e", indicating that this instruction is now part of the "else" ``` This is much shorter and should be more efficient, and the pass will only remove the VPNOT when VPR is used+killed by one instruction or when VPR is written to in its block. This should be enough to avoid losing the result of a VPNOT if it's needed, however I'm open to suggestions as I don't actually know if it's good enough. The patch also contains some minor formatting changes, as I ran clang-format on the file to format my code, and it changed old code as well, but I believe it's for the better. I can always revert if you want.

This patch enhances the MVE-VPT block insertion pass by allowing it to remove VPNOT instructions to place the predicated instructions in an "else" block,adds a feature to the MVE VPT block insertion patch: It can now remove VPNOT instructions in some circumstances in order to place the instructions predicated by the VPNOT in an else block instead; This resultings in more compact code. PreviouslyFor example, this pass used to generated this kind of assembly: ``` vldrw.u32 q1, [r5] vpt.s32 ge, q1, r2 ; Added by MVE-VPT block insertion pass vcmpt.s32 le, q1, r3 vpnot vpst ; Added by MVE-VPT block insertion pass vstrwt.32 q0, [r5], #16 ``` Now, when the VPNOT's result (stored in VPR) is not needed, and when the above block has enough room, it'll generate this instead: ``` vldrw.u32 q1, [r5] vpte.s32 ge, q1, r2 ; Added by MVE-VPT block insertion pass - Notice the "te" instead of "t" vcmpt.s32 le, q1, r3 vstrwe.32 q0, [r5], #16 ; "t" changed to "e", indicating that this instruction is now part of the "else" ``` This is much shorter and should be more efficient, and the pass will only remove the VPNOT when VPR is used+killed by one instruction or when VPR is written to in its block. This should be enough to avoid losing the result of a VPNOT if it's needed, however I'm open to suggestions as I don't actually know if it's good enough. The patch also contains some minor formatting changes, as I ran clang-format on the file to format my code, and it changed old code as well, but I believe it's for the better. I can always revert if you want.