From 413ebfd660793ce16f0e6173b38ad91cd2f0cf64 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Wed, 22 Nov 2023 01:18:27 +0000 Subject: [PATCH] RISC-V: Fold all the cond-move variants together Code in `riscv_expand_conditional_move' for Ventana and Zicond targets seems like bolted on as an afterthought rather than properly merged so as to handle all the cases together. Fold the existing code pieces together then (observing that for short forward branch targets no integer comparisons need to be canonicalized), letting T-Head targets produce branchless sequences for all the integer comparisons rather than for equality ones only, and preparing for the handling of floating-point comparisons here across all conditional-move targets. gcc/ * config/riscv/riscv.cc (riscv_expand_conditional_move): Unify conditional-move handling across all the relevant targets. --- gcc/config/riscv/riscv.cc | 60 +++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 34 deletions(-) diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index cdd1a4f9e254..4424882ec3a1 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -4119,35 +4119,9 @@ riscv_expand_conditional_move (rtx dest, rtx op, rtx cons, rtx alt) rtx_code code = GET_CODE (op); rtx op0 = XEXP (op, 0); rtx op1 = XEXP (op, 1); - bool need_eq_ne_p = false; - - if (TARGET_XTHEADCONDMOV - && GET_MODE_CLASS (mode) == MODE_INT - && (GET_MODE (op) == mode || GET_MODE (op) == E_VOIDmode) - && (GET_MODE (op0) == mode || CONST_INT_P (op0)) - && (GET_MODE (op1) == mode || CONST_INT_P (op1)) - && (code == EQ || code == NE)) - need_eq_ne_p = true; - - if (need_eq_ne_p - || (TARGET_SFB_ALU && GET_MODE (op0) == word_mode)) - { - riscv_emit_int_compare (&code, &op0, &op1, need_eq_ne_p); - rtx cond = gen_rtx_fmt_ee (code, GET_MODE (op0), op0, op1); - - /* The expander is a bit loose in its specification of the true - arm of the conditional move. That allows us to support more - cases for extensions which are more general than SFB. But - does mean we need to force CONS into a register at this point. */ - cons = force_reg (mode, cons); - /* With XTheadCondMov we need to force ALT into a register too. */ - alt = force_reg (mode, alt); - emit_insn (gen_rtx_SET (dest, gen_rtx_IF_THEN_ELSE (mode, - cond, cons, alt))); - return true; - } - else if (TARGET_ZICOND_LIKE - && GET_MODE_CLASS (mode) == MODE_INT) + + if ((TARGET_ZICOND_LIKE && GET_MODE_CLASS (mode) == MODE_INT) + || TARGET_SFB_ALU || TARGET_XTHEADCONDMOV) { machine_mode mode0 = GET_MODE (op0); machine_mode mode1 = GET_MODE (op1); @@ -4161,9 +4135,11 @@ riscv_expand_conditional_move (rtx dest, rtx op, rtx cons, rtx alt) return false; /* Canonicalize the comparison. It must be an equality comparison - of integer operands. If it isn't, then emit an SCC instruction + of integer operands, or with SFB it can be any comparison of + integer operands. If it isn't, then emit an SCC instruction so that we can then use an equality comparison against zero. */ - if (!equality_operator (op, VOIDmode) || !INTEGRAL_MODE_P (mode0)) + if ((!TARGET_SFB_ALU && !equality_operator (op, VOIDmode)) + || !INTEGRAL_MODE_P (mode0)) { bool *invert_ptr = nullptr; bool invert = false; @@ -4195,10 +4171,26 @@ riscv_expand_conditional_move (rtx dest, rtx op, rtx cons, rtx alt) op1 = XEXP (op, 1); } + if (TARGET_SFB_ALU || TARGET_XTHEADCONDMOV) + { + riscv_emit_int_compare (&code, &op0, &op1, !TARGET_SFB_ALU); + rtx cond = gen_rtx_fmt_ee (code, GET_MODE (op0), op0, op1); + + /* The expander is a bit loose in its specification of the true + arm of the conditional move. That allows us to support more + cases for extensions which are more general than SFB. But + does mean we need to force CONS into a register at this point. */ + cons = force_reg (mode, cons); + /* With XTheadCondMov we need to force ALT into a register too. */ + alt = force_reg (mode, alt); + emit_insn (gen_rtx_SET (dest, gen_rtx_IF_THEN_ELSE (mode, cond, + cons, alt))); + return true; + } /* 0, reg or 0, imm */ - if (cons == CONST0_RTX (mode) - && (REG_P (alt) - || (CONST_INT_P (alt) && alt != CONST0_RTX (mode)))) + else if (cons == CONST0_RTX (mode) + && (REG_P (alt) + || (CONST_INT_P (alt) && alt != CONST0_RTX (mode)))) { riscv_emit_int_compare (&code, &op0, &op1, true); rtx cond = gen_rtx_fmt_ee (code, GET_MODE (op0), op0, op1); -- 2.47.2