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tcg/i386: Optimize setcond of TST{EQ,NE} with 0xffffffff
This may be treated as a 32-bit EQ/NE comparison against 0, which is in turn treated as a LTU/GEU comparison against 1. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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@ -1658,6 +1658,7 @@ static void tcg_out_setcond(TCGContext *s, int rexw, TCGCond cond,
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TCGArg dest, TCGArg arg1, TCGArg arg2,
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TCGArg dest, TCGArg arg1, TCGArg arg2,
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int const_arg2, bool neg)
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int const_arg2, bool neg)
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{
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{
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int cmp_rexw = rexw;
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bool inv = false;
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bool inv = false;
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bool cleared;
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bool cleared;
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int jcc;
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int jcc;
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@ -1674,6 +1675,18 @@ static void tcg_out_setcond(TCGContext *s, int rexw, TCGCond cond,
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}
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}
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break;
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break;
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case TCG_COND_TSTNE:
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inv = true;
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/* fall through */
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case TCG_COND_TSTEQ:
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/* If arg2 is -1, convert to LTU/GEU vs 1. */
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if (const_arg2 && arg2 == 0xffffffffu) {
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arg2 = 1;
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cmp_rexw = 0;
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goto do_ltu;
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}
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break;
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case TCG_COND_LEU:
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case TCG_COND_LEU:
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inv = true;
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inv = true;
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/* fall through */
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/* fall through */
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@ -1697,7 +1710,7 @@ static void tcg_out_setcond(TCGContext *s, int rexw, TCGCond cond,
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* We can then use NEG or INC to produce the desired result.
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* We can then use NEG or INC to produce the desired result.
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* This is always smaller than the SETCC expansion.
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* This is always smaller than the SETCC expansion.
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*/
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*/
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tcg_out_cmp(s, TCG_COND_LTU, arg1, arg2, const_arg2, rexw);
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tcg_out_cmp(s, TCG_COND_LTU, arg1, arg2, const_arg2, cmp_rexw);
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/* X - X - C = -C = (C ? -1 : 0) */
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/* X - X - C = -C = (C ? -1 : 0) */
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tgen_arithr(s, ARITH_SBB + (neg ? rexw : 0), dest, dest);
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tgen_arithr(s, ARITH_SBB + (neg ? rexw : 0), dest, dest);
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@ -1744,7 +1757,7 @@ static void tcg_out_setcond(TCGContext *s, int rexw, TCGCond cond,
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cleared = true;
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cleared = true;
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}
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}
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jcc = tcg_out_cmp(s, cond, arg1, arg2, const_arg2, rexw);
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jcc = tcg_out_cmp(s, cond, arg1, arg2, const_arg2, cmp_rexw);
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tcg_out_modrm(s, OPC_SETCC | jcc, 0, dest);
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tcg_out_modrm(s, OPC_SETCC | jcc, 0, dest);
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if (!cleared) {
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if (!cleared) {
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