From ceb9ee06b719b3185183c72f818e75600c8e2607 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 23 Oct 2023 23:44:27 -0700 Subject: [PATCH] tcg/optimize: Handle TCG_COND_TST{EQ,NE} MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fold constant comparisons. Canonicalize "tst x,x" to equality vs zero. Canonicalize "tst x,sign" to sign test vs zero. Fold double-word comparisons with zero parts. Fold setcond of "tst x,pow2" to a bit extract. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Richard Henderson --- tcg/optimize.c | 240 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 218 insertions(+), 22 deletions(-) diff --git a/tcg/optimize.c b/tcg/optimize.c index 08a9280432..2ed6322f97 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -625,9 +625,15 @@ static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c) return x <= y; case TCG_COND_GTU: return x > y; - default: - g_assert_not_reached(); + case TCG_COND_TSTEQ: + return (x & y) == 0; + case TCG_COND_TSTNE: + return (x & y) != 0; + case TCG_COND_ALWAYS: + case TCG_COND_NEVER: + break; } + g_assert_not_reached(); } static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c) @@ -653,12 +659,18 @@ static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c) return x <= y; case TCG_COND_GTU: return x > y; - default: - g_assert_not_reached(); + case TCG_COND_TSTEQ: + return (x & y) == 0; + case TCG_COND_TSTNE: + return (x & y) != 0; + case TCG_COND_ALWAYS: + case TCG_COND_NEVER: + break; } + g_assert_not_reached(); } -static bool do_constant_folding_cond_eq(TCGCond c) +static int do_constant_folding_cond_eq(TCGCond c) { switch (c) { case TCG_COND_GT: @@ -673,9 +685,14 @@ static bool do_constant_folding_cond_eq(TCGCond c) case TCG_COND_LEU: case TCG_COND_EQ: return 1; - default: - g_assert_not_reached(); + case TCG_COND_TSTEQ: + case TCG_COND_TSTNE: + return -1; + case TCG_COND_ALWAYS: + case TCG_COND_NEVER: + break; } + g_assert_not_reached(); } /* @@ -703,8 +720,10 @@ static int do_constant_folding_cond(TCGType type, TCGArg x, } else if (arg_is_const_val(y, 0)) { switch (c) { case TCG_COND_LTU: + case TCG_COND_TSTNE: return 0; case TCG_COND_GEU: + case TCG_COND_TSTEQ: return 1; default: return -1; @@ -777,7 +796,30 @@ static int do_constant_folding_cond1(OptContext *ctx, TCGArg dest, } r = do_constant_folding_cond(ctx->type, *p1, *p2, cond); - return r; + if (r >= 0) { + return r; + } + if (!is_tst_cond(cond)) { + return -1; + } + + /* + * TSTNE x,x -> NE x,0 + * TSTNE x,-1 -> NE x,0 + */ + if (args_are_copies(*p1, *p2) || arg_is_const_val(*p2, -1)) { + *p2 = arg_new_constant(ctx, 0); + *pcond = tcg_tst_eqne_cond(cond); + return -1; + } + + /* TSTNE x,sign -> LT x,0 */ + if (arg_is_const_val(*p2, (ctx->type == TCG_TYPE_I32 + ? INT32_MIN : INT64_MIN))) { + *p2 = arg_new_constant(ctx, 0); + *pcond = tcg_tst_ltge_cond(cond); + } + return -1; } static int do_constant_folding_cond2(OptContext *ctx, TCGArg *args) @@ -785,6 +827,7 @@ static int do_constant_folding_cond2(OptContext *ctx, TCGArg *args) TCGArg al, ah, bl, bh; TCGCond c; bool swap; + int r; swap = swap_commutative2(args, args + 2); c = args[4]; @@ -806,21 +849,54 @@ static int do_constant_folding_cond2(OptContext *ctx, TCGArg *args) tcg_target_ulong alv = arg_info(al)->val; tcg_target_ulong ahv = arg_info(ah)->val; uint64_t a = deposit64(alv, 32, 32, ahv); - return do_constant_folding_cond_64(a, b, c); + + r = do_constant_folding_cond_64(a, b, c); + if (r >= 0) { + return r; + } } + if (b == 0) { switch (c) { case TCG_COND_LTU: + case TCG_COND_TSTNE: return 0; case TCG_COND_GEU: + case TCG_COND_TSTEQ: return 1; default: break; } } + + /* TSTNE x,-1 -> NE x,0 */ + if (b == -1 && is_tst_cond(c)) { + args[3] = args[2] = arg_new_constant(ctx, 0); + args[4] = tcg_tst_eqne_cond(c); + return -1; + } + + /* TSTNE x,sign -> LT x,0 */ + if (b == INT64_MIN && is_tst_cond(c)) { + /* bl must be 0, so copy that to bh */ + args[3] = bl; + args[4] = tcg_tst_ltge_cond(c); + return -1; + } } + if (args_are_copies(al, bl) && args_are_copies(ah, bh)) { - return do_constant_folding_cond_eq(c); + r = do_constant_folding_cond_eq(c); + if (r >= 0) { + return r; + } + + /* TSTNE x,x -> NE x,0 */ + if (is_tst_cond(c)) { + args[3] = args[2] = arg_new_constant(ctx, 0); + args[4] = tcg_tst_eqne_cond(c); + return -1; + } } return -1; } @@ -1284,24 +1360,37 @@ static bool fold_brcond2(OptContext *ctx, TCGOp *op) case 0: goto do_brcond_const; case 1: - op->opc = INDEX_op_brcond_i32; - op->args[1] = op->args[2]; - op->args[2] = cond; - op->args[3] = label; - break; + goto do_brcond_low; + } + break; + + case TCG_COND_TSTEQ: + case TCG_COND_TSTNE: + if (arg_is_const_val(op->args[2], 0)) { + goto do_brcond_high; + } + if (arg_is_const_val(op->args[3], 0)) { + goto do_brcond_low; } break; default: break; + do_brcond_low: + op->opc = INDEX_op_brcond_i32; + op->args[1] = op->args[2]; + op->args[2] = cond; + op->args[3] = label; + return fold_brcond(ctx, op); + do_brcond_high: op->opc = INDEX_op_brcond_i32; op->args[0] = op->args[1]; op->args[1] = op->args[3]; op->args[2] = cond; op->args[3] = label; - break; + return fold_brcond(ctx, op); do_brcond_const: if (i == 0) { @@ -1967,6 +2056,99 @@ static bool fold_remainder(OptContext *ctx, TCGOp *op) return false; } +static void fold_setcond_tst_pow2(OptContext *ctx, TCGOp *op, bool neg) +{ + TCGOpcode and_opc, sub_opc, xor_opc, neg_opc, shr_opc, uext_opc, sext_opc; + TCGCond cond = op->args[3]; + TCGArg ret, src1, src2; + TCGOp *op2; + uint64_t val; + int sh; + bool inv; + + if (!is_tst_cond(cond) || !arg_is_const(op->args[2])) { + return; + } + + src2 = op->args[2]; + val = arg_info(src2)->val; + if (!is_power_of_2(val)) { + return; + } + sh = ctz64(val); + + switch (ctx->type) { + case TCG_TYPE_I32: + and_opc = INDEX_op_and_i32; + sub_opc = INDEX_op_sub_i32; + xor_opc = INDEX_op_xor_i32; + shr_opc = INDEX_op_shr_i32; + neg_opc = INDEX_op_neg_i32; + if (TCG_TARGET_extract_i32_valid(sh, 1)) { + uext_opc = TCG_TARGET_HAS_extract_i32 ? INDEX_op_extract_i32 : 0; + sext_opc = TCG_TARGET_HAS_sextract_i32 ? INDEX_op_sextract_i32 : 0; + } + break; + case TCG_TYPE_I64: + and_opc = INDEX_op_and_i64; + sub_opc = INDEX_op_sub_i64; + xor_opc = INDEX_op_xor_i64; + shr_opc = INDEX_op_shr_i64; + neg_opc = INDEX_op_neg_i64; + if (TCG_TARGET_extract_i64_valid(sh, 1)) { + uext_opc = TCG_TARGET_HAS_extract_i64 ? INDEX_op_extract_i64 : 0; + sext_opc = TCG_TARGET_HAS_sextract_i64 ? INDEX_op_sextract_i64 : 0; + } + break; + default: + g_assert_not_reached(); + } + + ret = op->args[0]; + src1 = op->args[1]; + inv = cond == TCG_COND_TSTEQ; + + if (sh && sext_opc && neg && !inv) { + op->opc = sext_opc; + op->args[1] = src1; + op->args[2] = sh; + op->args[3] = 1; + return; + } else if (sh && uext_opc) { + op->opc = uext_opc; + op->args[1] = src1; + op->args[2] = sh; + op->args[3] = 1; + } else { + if (sh) { + op2 = tcg_op_insert_before(ctx->tcg, op, shr_opc, 3); + op2->args[0] = ret; + op2->args[1] = src1; + op2->args[2] = arg_new_constant(ctx, sh); + src1 = ret; + } + op->opc = and_opc; + op->args[1] = src1; + op->args[2] = arg_new_constant(ctx, 1); + } + + if (neg && inv) { + op2 = tcg_op_insert_after(ctx->tcg, op, sub_opc, 3); + op2->args[0] = ret; + op2->args[1] = ret; + op2->args[2] = arg_new_constant(ctx, 1); + } else if (inv) { + op2 = tcg_op_insert_after(ctx->tcg, op, xor_opc, 3); + op2->args[0] = ret; + op2->args[1] = ret; + op2->args[2] = arg_new_constant(ctx, 1); + } else if (neg) { + op2 = tcg_op_insert_after(ctx->tcg, op, neg_opc, 2); + op2->args[0] = ret; + op2->args[1] = ret; + } +} + static bool fold_setcond(OptContext *ctx, TCGOp *op) { int i = do_constant_folding_cond1(ctx, op->args[0], &op->args[1], @@ -1974,6 +2156,7 @@ static bool fold_setcond(OptContext *ctx, TCGOp *op) if (i >= 0) { return tcg_opt_gen_movi(ctx, op, op->args[0], i); } + fold_setcond_tst_pow2(ctx, op, false); ctx->z_mask = 1; ctx->s_mask = smask_from_zmask(1); @@ -1987,13 +2170,13 @@ static bool fold_negsetcond(OptContext *ctx, TCGOp *op) if (i >= 0) { return tcg_opt_gen_movi(ctx, op, op->args[0], -i); } + fold_setcond_tst_pow2(ctx, op, true); /* Value is {0,-1} so all bits are repetitions of the sign. */ ctx->s_mask = -1; return false; } - static bool fold_setcond2(OptContext *ctx, TCGOp *op) { TCGCond cond; @@ -2041,22 +2224,35 @@ static bool fold_setcond2(OptContext *ctx, TCGOp *op) case 0: goto do_setcond_const; case 1: - op->args[2] = op->args[3]; - op->args[3] = cond; - op->opc = INDEX_op_setcond_i32; - break; + goto do_setcond_low; + } + break; + + case TCG_COND_TSTEQ: + case TCG_COND_TSTNE: + if (arg_is_const_val(op->args[2], 0)) { + goto do_setcond_high; + } + if (arg_is_const_val(op->args[4], 0)) { + goto do_setcond_low; } break; default: break; + do_setcond_low: + op->args[2] = op->args[3]; + op->args[3] = cond; + op->opc = INDEX_op_setcond_i32; + return fold_setcond(ctx, op); + do_setcond_high: op->args[1] = op->args[2]; op->args[2] = op->args[4]; op->args[3] = cond; op->opc = INDEX_op_setcond_i32; - break; + return fold_setcond(ctx, op); } ctx->z_mask = 1;