[Qemu-devel] [PULL 08/31] tcg: Support cross-class moves without instruction support

[Richard Henderson]

PowerPC Altivec does not support direct moves between vector registers
and general registers.  So when tcg_out_mov fails, we can use the
backing memory for the temporary to perform the move.

Acked-by: David Hildenbrand <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
 tcg/tcg.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/tcg/tcg.c b/tcg/tcg.c
index 8ed7cb8654..68d86361e2 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -3368,7 +3368,20 @@ static void tcg_reg_alloc_mov(TCGContext *s, const TCGOp 
*op)
                                          ots->indirect_base);
             }
             if (!tcg_out_mov(s, otype, ots->reg, ts->reg)) {
-                abort();
+                /*
+                 * Cross register class move not supported.
+                 * Store the source register into the destination slot
+                 * and leave the destination temp as TEMP_VAL_MEM.
+                 */
+                assert(!ots->fixed_reg);
+                if (!ts->mem_allocated) {
+                    temp_allocate_frame(s, ots);
+                }
+                tcg_out_st(s, ts->type, ts->reg,
+                           ots->mem_base->reg, ots->mem_offset);
+                ots->mem_coherent = 1;
+                temp_free_or_dead(s, ots, -1);
+                return;
             }
         }
         ots->val_type = TEMP_VAL_REG;
@@ -3470,7 +3483,13 @@ static void tcg_reg_alloc_op(TCGContext *s, const TCGOp 
*op)
             reg = tcg_reg_alloc(s, arg_ct->u.regs, i_allocated_regs,
                                 o_preferred_regs, ts->indirect_base);
             if (!tcg_out_mov(s, ts->type, reg, ts->reg)) {
-                abort();
+                /*
+                 * Cross register class move not supported.  Sync the
+                 * temp back to its slot and load from there.
+                 */
+                temp_sync(s, ts, i_allocated_regs, 0, 0);
+                tcg_out_ld(s, ts->type, reg,
+                           ts->mem_base->reg, ts->mem_offset);
             }
         }
         new_args[i] = reg;
@@ -3631,7 +3650,13 @@ static void tcg_reg_alloc_call(TCGContext *s, TCGOp *op)
                 if (ts->reg != reg) {
                     tcg_reg_free(s, reg, allocated_regs);
                     if (!tcg_out_mov(s, ts->type, reg, ts->reg)) {
-                        abort();
+                        /*
+                         * Cross register class move not supported.  Sync the
+                         * temp back to its slot and load from there.
+                         */
+                        temp_sync(s, ts, allocated_regs, 0, 0);
+                        tcg_out_ld(s, ts->type, reg,
+                                   ts->mem_base->reg, ts->mem_offset);
                     }
                 }
             } else {
-- 
2.17.1