[Qemu-devel] [PATCH v2 07/10] target-arm: optimize thumb2 load/store multiple ops

[juha . riihimaki]

From: Juha Riihimäki <address@hidden>

Thumb2 load/store multiple instructions can be slightly optimized by
loading the register offset constant into a variable outside the
register loop and using the preloaded variable inside the loop instead
of reloading the offset value to a temporary variable on each loop
iteration. This causes less TCG ops to be generated for a Thumb2 load/
store multiple instruction if there are more than one register
accessed, otherwise the amount of generated TCG ops will be the same.

Signed-off-by: Juha Riihimäki <address@hidden>
---
 target-arm/translate.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 9e924d4..353f638 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -7374,6 +7374,7 @@ static int disas_thumb2_insn(CPUState *env, DisasContext 
*s, uint16_t insn_hw1)
                     tcg_gen_addi_i32(addr, addr, -offset);
                 }
 
+                tmp2 = tcg_const_i32(4);
                 for (i = 0; i < 16; i++) {
                     if ((insn & (1 << i)) == 0)
                         continue;
@@ -7390,8 +7391,9 @@ static int disas_thumb2_insn(CPUState *env, DisasContext 
*s, uint16_t insn_hw1)
                         tmp = load_reg(s, i);
                         gen_st32(tmp, addr, IS_USER(s));
                     }
-                    tcg_gen_addi_i32(addr, addr, 4);
+                    tcg_gen_add_i32(addr, addr, tmp2);
                 }
+                tcg_temp_free_i32(tmp2);
                 if (insn & (1 << 21)) {
                     /* Base register writeback.  */
                     if (insn & (1 << 24)) {
-- 
1.6.5