[Qemu-devel] [PATCH 3/3] Replace some register operations by direct usage of cpu_R[i] TCG variables.

[Filip Navara]

Various operations could be optimized by removing the temporary TCG variables 
that were used and using cpu_R[i] TCG variables directly. Care must be taken 
not to use cpu_R[15] directly since it's the program counter register and it's 
not updated during the translation.
---
 target-arm/translate.c |   70 +++++++++++++++---------------------------------
 1 files changed, 22 insertions(+), 48 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 2b8b770..d0ec568 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -1506,9 +1506,7 @@ static int disas_iwmmxt_insn(CPUState *env, DisasContext 
*s, uint32_t insn)
             return 1;
         if (insn & ARM_CP_RW_BIT) {
             if ((insn >> 28) == 0xf) {                 /* WLDRW wCx */
-                tmp = gen_ld32(cpu_T[1], IS_USER(s));
-                tcg_gen_mov_i32(cpu_T[0], tmp);
-                dead_tmp(tmp);
+                tcg_gen_qemu_ld32u(cpu_T[0], cpu_T[1], IS_USER(s));
                 gen_op_iwmmxt_movl_wCx_T0(wrd);
             } else {
                 i = 1;
@@ -3867,18 +3865,11 @@ static int disas_neon_ls_insn(CPUState * env, 
DisasContext *s, uint32_t insn)
         }
     }
     if (rm != 15) {
-        TCGv base;
-
-        base = load_reg(s, rn);
         if (rm == 13) {
-            tcg_gen_addi_i32(base, base, stride);
+            tcg_gen_addi_i32(cpu_R[rn], cpu_R[rn], stride);
         } else {
-            TCGv index;
-            index = load_reg(s, rm);
-            tcg_gen_add_i32(base, base, index);
-            dead_tmp(index);
+            tcg_gen_add_i32(cpu_R[rn], cpu_R[rn], cpu_R[rm]);
         }
-        store_reg(s, rn, base);
     }
     return 0;
 }
@@ -5780,8 +5771,7 @@ static void disas_arm_insn(CPUState * env, DisasContext 
*s)
             }
             if (offset)
                 tcg_gen_addi_i32(addr, addr, offset);
-            tmp = load_reg(s, 14);
-            gen_st32(tmp, addr, 0);
+            tcg_gen_qemu_st32(cpu_R[14], addr, 0);
             tmp = new_tmp();
             gen_helper_cpsr_read(tmp);
             tcg_gen_addi_i32(addr, addr, 4);
@@ -7470,21 +7460,18 @@ static int disas_thumb2_insn(CPUState *env, 
DisasContext *s, uint16_t insn_hw1)
                 tcg_gen_mul_i32(tmp, tmp, tmp2);
                 dead_tmp(tmp2);
                 if (rs != 15) {
-                    tmp2 = load_reg(s, rs);
-                    if (op)
-                        tcg_gen_sub_i32(tmp, tmp2, tmp);
-                    else
-                        tcg_gen_add_i32(tmp, tmp, tmp2);
-                    dead_tmp(tmp2);
+                    if (op) {
+                        tcg_gen_sub_i32(tmp, cpu_R[rs], tmp);
+                    } else {
+                        tcg_gen_add_i32(tmp, tmp, cpu_R[rs]);
+                    }
                 }
                 break;
             case 1: /* 16 x 16 -> 32 */
                 gen_mulxy(tmp, tmp2, op & 2, op & 1);
                 dead_tmp(tmp2);
                 if (rs != 15) {
-                    tmp2 = load_reg(s, rs);
-                    gen_helper_add_setq(tmp, tmp, tmp2);
-                    dead_tmp(tmp2);
+                    gen_helper_add_setq(tmp, tmp, cpu_R[rs]);
                 }
                 break;
             case 2: /* Dual multiply add.  */
@@ -7499,12 +7486,9 @@ static int disas_thumb2_insn(CPUState *env, DisasContext 
*s, uint16_t insn_hw1)
                     tcg_gen_add_i32(tmp, tmp, tmp2);
                 }
                 dead_tmp(tmp2);
-                if (rs != 15)
-                  {
-                    tmp2 = load_reg(s, rs);
-                    gen_helper_add_setq(tmp, tmp, tmp2);
-                    dead_tmp(tmp2);
-                  }
+                if (rs != 15) {
+                    gen_helper_add_setq(tmp, tmp, cpu_R[rs]);
+                }
                 break;
             case 3: /* 32 * 16 -> 32msb */
                 if (op)
@@ -7515,12 +7499,9 @@ static int disas_thumb2_insn(CPUState *env, DisasContext 
*s, uint16_t insn_hw1)
                 tcg_gen_shri_i64(tmp64, tmp64, 16);
                 tmp = new_tmp();
                 tcg_gen_trunc_i64_i32(tmp, tmp64);
-                if (rs != 15)
-                  {
-                    tmp2 = load_reg(s, rs);
-                    gen_helper_add_setq(tmp, tmp, tmp2);
-                    dead_tmp(tmp2);
-                  }
+                if (rs != 15) {
+                    gen_helper_add_setq(tmp, tmp, cpu_R[rs]);
+                }
                 break;
             case 5: case 6: /* 32 * 32 -> 32msb */
                 gen_imull(tmp, tmp2);
@@ -7532,22 +7513,18 @@ static int disas_thumb2_insn(CPUState *env, 
DisasContext *s, uint16_t insn_hw1)
                     tmp = tmp2;
                 }
                 if (rs != 15) {
-                    tmp2 = load_reg(s, rs);
                     if (insn & (1 << 21)) {
-                        tcg_gen_add_i32(tmp, tmp, tmp2);
+                        tcg_gen_add_i32(tmp, tmp, cpu_R[rs]);
                     } else {
-                        tcg_gen_sub_i32(tmp, tmp2, tmp);
+                        tcg_gen_sub_i32(tmp, cpu_R[rs], tmp);
                     }
-                    dead_tmp(tmp2);
                 }
                 break;
             case 7: /* Unsigned sum of absolute differences.  */
                 gen_helper_usad8(tmp, tmp, tmp2);
                 dead_tmp(tmp2);
                 if (rs != 15) {
-                    tmp2 = load_reg(s, rs);
-                    tcg_gen_add_i32(tmp, tmp, tmp2);
-                    dead_tmp(tmp2);
+                    tcg_gen_add_i32(tmp, tmp, cpu_R[rs]);
                 }
                 break;
             }
@@ -8498,12 +8475,10 @@ static void disas_thumb_insn(CPUState *env, 
DisasContext *s)
                 if (insn & (1 << i)) {
                     if (insn & (1 << 11)) {
                         /* pop */
-                        tmp = gen_ld32(addr, IS_USER(s));
-                        store_reg(s, i, tmp);
+                        tcg_gen_qemu_ld32u(cpu_R[i], addr, IS_USER(s));
                     } else {
                         /* push */
-                        tmp = load_reg(s, i);
-                        gen_st32(tmp, addr, IS_USER(s));
+                        tcg_gen_qemu_st32(cpu_R[i], addr, IS_USER(s));
                     }
                     /* advance to the next address.  */
                     tcg_gen_addi_i32(addr, addr, 4);
@@ -8518,8 +8493,7 @@ static void disas_thumb_insn(CPUState *env, DisasContext 
*s)
                        has completed */
                 } else {
                     /* push lr */
-                    tmp = load_reg(s, 14);
-                    gen_st32(tmp, addr, IS_USER(s));
+                    tcg_gen_qemu_st32(cpu_R[14], addr, IS_USER(s));
                 }
                 tcg_gen_addi_i32(addr, addr, 4);
             }
-- 
1.6.3.msysgit.0