With x86_64 as host, we do not have any temporaries with which to resolve cycles, but we do have xchg. As a side bonus, the set of graphs that can be made with 3 nodes and all nodes conflicting is small: two. We can solve the cycle with a single temp.
This is required for x86_64 to handle stores of i128: 1 address register and 2 data registers. Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- tcg/tcg.c | 138 ++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 107 insertions(+), 31 deletions(-) diff --git a/tcg/tcg.c b/tcg/tcg.c index aa0a6c3763..8688248284 100644 --- a/tcg/tcg.c +++ b/tcg/tcg.c @@ -532,6 +532,82 @@ static void tcg_out_movext2(TCGContext *s, const TCGMovExtend *i1, tcg_out_movext1_new_src(s, i1, src1); } +/** + * tcg_out_movext3 -- move and extend three pair + * @s: tcg context + * @i1: first move description + * @i2: second move description + * @i3: third move description + * @scratch: temporary register, or -1 for none + * + * As tcg_out_movext, for all of @i1, @i2 and @i3, caring for overlap + * between the sources and destinations. + */ + +static void tcg_out_movext3(TCGContext *s, const TCGMovExtend *i1, + const TCGMovExtend *i2, const TCGMovExtend *i3, + int scratch) +{ + TCGReg src1 = i1->src; + TCGReg src2 = i2->src; + TCGReg src3 = i3->src; + + if (i1->dst != src2 && i1->dst != src3) { + tcg_out_movext1(s, i1); + tcg_out_movext2(s, i2, i3, scratch); + return; + } + if (i2->dst != src1 && i2->dst != src3) { + tcg_out_movext1(s, i2); + tcg_out_movext2(s, i1, i3, scratch); + return; + } + if (i3->dst != src1 && i3->dst != src2) { + tcg_out_movext1(s, i3); + tcg_out_movext2(s, i1, i2, scratch); + return; + } + + /* + * There is a cycle. Since there are only 3 nodes, the cycle is + * either "clockwise" or "anti-clockwise", and can be solved with + * a single scratch or two xchg. + */ + if (i1->dst == src2 && i2->dst == src3 && i3->dst == src1) { + /* "Clockwise" */ + if (tcg_out_xchg(s, MAX(i1->src_type, i2->src_type), src1, src2)) { + tcg_out_xchg(s, MAX(i2->src_type, i3->src_type), src2, src3); + /* The data is now in the correct registers, now extend. */ + tcg_out_movext1_new_src(s, i1, i1->dst); + tcg_out_movext1_new_src(s, i2, i2->dst); + tcg_out_movext1_new_src(s, i3, i3->dst); + } else { + tcg_debug_assert(scratch >= 0); + tcg_out_mov(s, i1->src_type, scratch, src1); + tcg_out_movext1(s, i3); + tcg_out_movext1(s, i2); + tcg_out_movext1_new_src(s, i1, scratch); + } + } else if (i1->dst == src3 && i2->dst == src1 && i3->dst == src2) { + /* "Anti-clockwise" */ + if (tcg_out_xchg(s, MAX(i2->src_type, i3->src_type), src2, src3)) { + tcg_out_xchg(s, MAX(i1->src_type, i2->src_type), src1, src2); + /* The data is now in the correct registers, now extend. */ + tcg_out_movext1_new_src(s, i1, i1->dst); + tcg_out_movext1_new_src(s, i2, i2->dst); + tcg_out_movext1_new_src(s, i3, i3->dst); + } else { + tcg_debug_assert(scratch >= 0); + tcg_out_mov(s, i1->src_type, scratch, src1); + tcg_out_movext1(s, i2); + tcg_out_movext1(s, i3); + tcg_out_movext1_new_src(s, i1, scratch); + } + } else { + g_assert_not_reached(); + } +} + #define C_PFX1(P, A) P##A #define C_PFX2(P, A, B) P##A##_##B #define C_PFX3(P, A, B, C) P##A##_##B##_##C @@ -5149,46 +5225,46 @@ static int tcg_out_helper_stk_ofs(TCGType type, unsigned slot) static void tcg_out_helper_load_regs(TCGContext *s, unsigned nmov, TCGMovExtend *mov, - unsigned ntmp, const int *tmp) + const TCGLdstHelperParam *parm) { + TCGReg dst3; + switch (nmov) { - default: + case 4: /* The backend must have provided enough temps for the worst case. */ - tcg_debug_assert(ntmp + 1 >= nmov); + tcg_debug_assert(parm->ntmp >= 2); - for (unsigned i = nmov - 1; i >= 2; --i) { - TCGReg dst = mov[i].dst; - - for (unsigned j = 0; j < i; ++j) { - if (dst == mov[j].src) { - /* - * Conflict. - * Copy the source to a temporary, recurse for the - * remaining moves, perform the extension from our - * scratch on the way out. - */ - TCGReg scratch = tmp[--ntmp]; - tcg_out_mov(s, mov[i].src_type, scratch, mov[i].src); - mov[i].src = scratch; - - tcg_out_helper_load_regs(s, i, mov, ntmp, tmp); - tcg_out_movext1(s, &mov[i]); - return; - } + dst3 = mov[3].dst; + for (unsigned j = 0; j < 3; ++j) { + if (dst3 == mov[j].src) { + /* + * Conflict. Copy the source to a temporary, perform the + * remaining moves, then the extension from our scratch + * on the way out. + */ + TCGReg scratch = parm->tmp[1]; + tcg_out_movext3(s, mov, mov + 1, mov + 2, parm->tmp[0]); + tcg_out_movext1_new_src(s, &mov[3], scratch); + break; } - - /* No conflicts: perform this move and continue. */ - tcg_out_movext1(s, &mov[i]); } - /* fall through for the final two moves */ + /* No conflicts: perform this move and continue. */ + tcg_out_movext1(s, &mov[3]); + /* fall through */ + + case 3: + tcg_out_movext3(s, mov, mov + 1, mov + 2, + parm->ntmp ? parm->tmp[0] : -1); + break; case 2: - tcg_out_movext2(s, mov, mov + 1, ntmp ? tmp[0] : -1); - return; + tcg_out_movext2(s, mov, mov + 1, + parm->ntmp ? parm->tmp[0] : -1); + break; case 1: tcg_out_movext1(s, mov); - return; - case 0: + break; + default: g_assert_not_reached(); } } @@ -5235,7 +5311,7 @@ static void tcg_out_helper_load_slots(TCGContext *s, for (i = 0; i < nmov; ++i) { mov[i].dst = tcg_target_call_iarg_regs[mov[i].dst]; } - tcg_out_helper_load_regs(s, nmov, mov, parm->ntmp, parm->tmp); + tcg_out_helper_load_regs(s, nmov, mov, parm); } static void tcg_out_helper_load_imm(TCGContext *s, unsigned slot, -- 2.34.1