target/microblaze: Drop DisasContext.r0

Return a constant 0 from reg_for_read, and a new
temporary from reg_for_write.

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 2 insertions, 22 deletions

diff --git a/target/microblaze/translate.c b/target/microblaze/translate.c
index dc597b3..047d97e 100644
--- a/target/microblaze/translate.c
+++ b/target/microblaze/translate.c
@@ -63,9 +63,6 @@ typedef struct DisasContext {
     DisasContextBase base;
     const MicroBlazeCPUConfig *cfg;
 
-    TCGv_i32 r0;
-    bool r0_set;
-
     /* Decoder.  */
     uint32_t ext_imm;
     unsigned int tb_flags;
@@ -179,14 +176,7 @@ static TCGv_i32 reg_for_read(DisasContext *dc, int reg)
     if (likely(reg != 0)) {
         return cpu_R[reg];
     }
-    if (!dc->r0_set) {
-        if (dc->r0 == NULL) {
-            dc->r0 = tcg_temp_new_i32();
-        }
-        tcg_gen_movi_i32(dc->r0, 0);
-        dc->r0_set = true;
-    }
-    return dc->r0;
+    return tcg_constant_i32(0);
 }
 
 static TCGv_i32 reg_for_write(DisasContext *dc, int reg)
@@ -194,10 +184,7 @@ static TCGv_i32 reg_for_write(DisasContext *dc, int reg)
     if (likely(reg != 0)) {
         return cpu_R[reg];
     }
-    if (dc->r0 == NULL) {
-        dc->r0 = tcg_temp_new_i32();
-    }
-    return dc->r0;
+    return tcg_temp_new_i32();
 }
 
 static bool do_typea(DisasContext *dc, arg_typea *arg, bool side_effects,
@@ -1635,8 +1622,6 @@ static void mb_tr_init_disas_context(DisasContextBase *dcb, CPUState *cs)
     dc->cfg = &cpu->cfg;
     dc->tb_flags = dc->base.tb->flags;
     dc->ext_imm = dc->base.tb->cs_base;
-    dc->r0 = NULL;
-    dc->r0_set = false;
     dc->mem_index = cpu_mmu_index(cs, false);
     dc->jmp_cond = dc->tb_flags & D_FLAG ? TCG_COND_ALWAYS : TCG_COND_NEVER;
     dc->jmp_dest = -1;
@@ -1675,11 +1660,6 @@ static void mb_tr_translate_insn(DisasContextBase *dcb, CPUState *cs)
         trap_illegal(dc, true);
     }
 
-    if (dc->r0) {
-        dc->r0 = NULL;
-        dc->r0_set = false;
-    }
-
     /* Discard the imm global when its contents cannot be used. */
     if ((dc->tb_flags & ~dc->tb_flags_to_set) & IMM_FLAG) {
         tcg_gen_discard_i32(cpu_imm);