From d066ca3575e1aba706bafb1a434f5d7765c10181 Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Fri, 26 Jul 2019 13:32:54 -0700 Subject: [PATCH] pan/midgard: Add bitwise src/invert fusing De Morgan's Laws and some special ops basically. Signed-off-by: Alyssa Rosenzweig --- src/panfrost/midgard/compiler.h | 1 + src/panfrost/midgard/midgard_compile.c | 1 + src/panfrost/midgard/midgard_opt_invert.c | 122 ++++++++++++++++++++++ 3 files changed, 124 insertions(+) diff --git a/src/panfrost/midgard/compiler.h b/src/panfrost/midgard/compiler.h index cf9db9145a3..2aad68f14dd 100644 --- a/src/panfrost/midgard/compiler.h +++ b/src/panfrost/midgard/compiler.h @@ -577,6 +577,7 @@ void midgard_opt_post_move_eliminate(compiler_context *ctx, midgard_block *block void midgard_lower_invert(compiler_context *ctx, midgard_block *block); bool midgard_opt_not_propagate(compiler_context *ctx, midgard_block *block); +bool midgard_opt_fuse_src_invert(compiler_context *ctx, midgard_block *block); bool midgard_opt_fuse_dest_invert(compiler_context *ctx, midgard_block *block); #endif diff --git a/src/panfrost/midgard/midgard_compile.c b/src/panfrost/midgard/midgard_compile.c index a3c66ca43bb..c4a50cbaee0 100644 --- a/src/panfrost/midgard/midgard_compile.c +++ b/src/panfrost/midgard/midgard_compile.c @@ -2358,6 +2358,7 @@ midgard_compile_shader_nir(struct midgard_screen *screen, nir_shader *nir, midga progress |= midgard_opt_combine_projection(ctx, block); progress |= midgard_opt_varying_projection(ctx, block); progress |= midgard_opt_not_propagate(ctx, block); + progress |= midgard_opt_fuse_src_invert(ctx, block); progress |= midgard_opt_fuse_dest_invert(ctx, block); } } while (progress); diff --git a/src/panfrost/midgard/midgard_opt_invert.c b/src/panfrost/midgard/midgard_opt_invert.c index ffe43a1b176..6a6be1d83ff 100644 --- a/src/panfrost/midgard/midgard_opt_invert.c +++ b/src/panfrost/midgard/midgard_opt_invert.c @@ -132,6 +132,32 @@ mir_invert_op(midgard_alu_op op) } } +static midgard_alu_op +mir_demorgan_op(midgard_alu_op op) +{ + switch (op) { + case midgard_alu_op_iand: + return midgard_alu_op_inor; + case midgard_alu_op_ior: + return midgard_alu_op_inand; + default: + unreachable("Op not De Morgan-able"); + } +} + +static midgard_alu_op +mir_notright_op(midgard_alu_op op) +{ + switch (op) { + case midgard_alu_op_iand: + return midgard_alu_op_iandnot; + case midgard_alu_op_ior: + return midgard_alu_op_iornot; + default: + unreachable("Op not right able"); + } +} + bool midgard_opt_fuse_dest_invert(compiler_context *ctx, midgard_block *block) { @@ -150,3 +176,99 @@ midgard_opt_fuse_dest_invert(compiler_context *ctx, midgard_block *block) return progress; } + +/* Next up, we can fuse inverts into the sources of bitwise ops: + * + * ~a & b = b & ~a = iandnot(b, a) + * a & ~b = iandnot(a, b) + * ~a & ~b = ~(a | b) = inor(a, b) + * + * ~a | b = b | ~a = iornot(b, a) + * a | ~b = iornot(a, b) + * ~a | ~b = ~(a & b) = inand(a, b) + * + * ~a ^ b = ~(a ^ b) = inxor(a, b) + * a ^ ~b = ~(a ^ b) + inxor(a, b) + * ~a ^ ~b = a ^ b + * ~(a ^ b) = inxor(a, b) + */ + +static bool +mir_strip_inverted(compiler_context *ctx, unsigned node) +{ + /* Strips and returns the invert off a node */ + mir_foreach_instr_global(ctx, ins) { + if (ins->compact_branch) continue; + if (ins->ssa_args.dest != node) continue; + + bool status = ins->invert; + ins->invert = false; + return status; + } + + unreachable("Invalid node stripped"); +} + +bool +midgard_opt_fuse_src_invert(compiler_context *ctx, midgard_block *block) +{ + bool progress = false; + + mir_foreach_instr_in_block_safe(block, ins) { + /* Search for inverted bitwise */ + if (ins->type != TAG_ALU_4) continue; + if (!mir_is_bitwise(ins)) continue; + if (ins->invert) continue; + + if (ins->ssa_args.src0 & IS_REG) continue; + if (ins->ssa_args.src1 & IS_REG) continue; + if (!mir_single_use(ctx, ins->ssa_args.src0)) continue; + if (!ins->ssa_args.inline_constant && !mir_single_use(ctx, ins->ssa_args.src1)) continue; + + bool not_a = mir_strip_inverted(ctx, ins->ssa_args.src0); + bool not_b = + ins->ssa_args.inline_constant ? false : + mir_strip_inverted(ctx, ins->ssa_args.src1); + + /* Edge case: if src0 == src1, it'll've been stripped */ + if ((ins->ssa_args.src0 == ins->ssa_args.src1) && !ins->ssa_args.inline_constant) + not_b = not_a; + + progress |= (not_a || not_b); + + /* No point */ + if (!(not_a || not_b)) continue; + + bool both = not_a && not_b; + bool left = not_a && !not_b; + bool right = !not_a && not_b; + + /* No-op, but we got to strip the inverts */ + if (both && ins->alu.op == midgard_alu_op_ixor) + continue; + + if (both) { + ins->alu.op = mir_demorgan_op(ins->alu.op); + } else if (right || (left && !ins->ssa_args.inline_constant)) { + if (left) { + /* Commute */ + unsigned temp = ins->ssa_args.src0; + ins->ssa_args.src0 = ins->ssa_args.src1; + ins->ssa_args.src1 = temp; + } + + ins->alu.op = mir_notright_op(ins->alu.op); + } else if (left && ins->ssa_args.inline_constant) { + /* Some special transformations: + * + * ~A & c = ~(~(~A) | (~c)) = ~(A | ~c) = inor(A, ~c) + * ~A | c = ~(~(~A) & (~c)) = ~(A & ~c) = inand(A, ~c) + */ + + ins->alu.op = mir_demorgan_op(ins->alu.op); + ins->inline_constant = ~ins->inline_constant; + } + } + + return progress; +} -- 2.30.2