target/arm: Fix temp double-free in sve ldr/str

The temp that gets assigned to clean_addr has been allocated with
new_tmp_a64, which means that it will be freed at the end of the
instruction.  Freeing it earlier leads to assertion failure.

The loop creates a complication, in which we allocate a new local
temp, which does need freeing, and the final code path is shared
between the loop and non-loop.

Fix this complication by adding new_tmp_a64_local so that the new
local temp is freed at the end, and can be treated exactly like
the non-loop path.

Fixes: bba87d0a0f
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20200702175605.1987125-1-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/translate-a64.c

@@ -461,6 +461,12 @@ TCGv_i64 new_tmp_a64(DisasContext *s)
     return s->tmp_a64[s->tmp_a64_count++] = tcg_temp_new_i64();
 }
 
+TCGv_i64 new_tmp_a64_local(DisasContext *s)
+{
+    assert(s->tmp_a64_count < TMP_A64_MAX);
+    return s->tmp_a64[s->tmp_a64_count++] = tcg_temp_local_new_i64();
+}
+
 TCGv_i64 new_tmp_a64_zero(DisasContext *s)
 {
     TCGv_i64 t = new_tmp_a64(s);

target/arm/translate-a64.h

@@ -30,6 +30,7 @@ void unallocated_encoding(DisasContext *s);
     } while (0)
 
 TCGv_i64 new_tmp_a64(DisasContext *s);
+TCGv_i64 new_tmp_a64_local(DisasContext *s);
 TCGv_i64 new_tmp_a64_zero(DisasContext *s);
 TCGv_i64 cpu_reg(DisasContext *s, int reg);
 TCGv_i64 cpu_reg_sp(DisasContext *s, int reg);

target/arm/translate-sve.c

@@ -4372,9 +4372,8 @@ static void do_ldr(DisasContext *s, uint32_t vofs, int len, int rn, int imm)
 
         /* Copy the clean address into a local temp, live across the loop. */
         t0 = clean_addr;
-        clean_addr = tcg_temp_local_new_i64();
+        clean_addr = new_tmp_a64_local(s);
         tcg_gen_mov_i64(clean_addr, t0);
-        tcg_temp_free_i64(t0);
 
         gen_set_label(loop);
 
@@ -4422,7 +4421,6 @@ static void do_ldr(DisasContext *s, uint32_t vofs, int len, int rn, int imm)
         tcg_gen_st_i64(t0, cpu_env, vofs + len_align);
         tcg_temp_free_i64(t0);
     }
-    tcg_temp_free_i64(clean_addr);
 }
 
 /* Similarly for stores.  */
@@ -4463,9 +4461,8 @@ static void do_str(DisasContext *s, uint32_t vofs, int len, int rn, int imm)
 
         /* Copy the clean address into a local temp, live across the loop. */
         t0 = clean_addr;
-        clean_addr = tcg_temp_local_new_i64();
+        clean_addr = new_tmp_a64_local(s);
         tcg_gen_mov_i64(clean_addr, t0);
-        tcg_temp_free_i64(t0);
 
         gen_set_label(loop);
 
@@ -4509,7 +4506,6 @@ static void do_str(DisasContext *s, uint32_t vofs, int len, int rn, int imm)
         }
         tcg_temp_free_i64(t0);
     }
-    tcg_temp_free_i64(clean_addr);
 }
 
 static bool trans_LDR_zri(DisasContext *s, arg_rri *a)