Patchwork [08/21] tcg-i386: Eliminate extra move from qemu_ld64.

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Submitter Richard Henderson
Date April 14, 2010, 3:06 p.m.
Message ID <febb33628413c7b3b541314a32af0fa8f8a1bd85.1271277329.git.rth@twiddle.net>
Download mbox | patch
Permalink /patch/50187/
State New
Headers show

Comments

Richard Henderson - April 14, 2010, 3:06 p.m.
If the address register overlaps one of the output registers
simply issue the clobbering load last, rather than emitting
an extra move of the address register.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 tcg/i386/tcg-target.c |   20 +++++++++-----------
 1 files changed, 9 insertions(+), 11 deletions(-)

Patch

diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index 4f7df70..5829c5b 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -787,22 +787,20 @@  static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
         }
         break;
     case 3:
-        /* XXX: could be nicer */
-        if (r0 == data_reg) {
-            r1 = TCG_REG_EDX;
-            if (r1 == data_reg)
-                r1 = TCG_REG_EAX;
-            tcg_out_mov(s, r1, r0);
-            r0 = r1;
+        if (bswap) {
+            int t = data_reg;
+            data_reg = data_reg2;
+            data_reg2 = t;
         }
-        if (!bswap) {
+        if (r0 != data_reg) {
             tcg_out_ld(s, TCG_TYPE_I32, data_reg, r0, GUEST_BASE);
             tcg_out_ld(s, TCG_TYPE_I32, data_reg2, r0, GUEST_BASE + 4);
         } else {
-            tcg_out_ld(s, TCG_TYPE_I32, data_reg, r0, GUEST_BASE + 4);
+            tcg_out_ld(s, TCG_TYPE_I32, data_reg2, r0, GUEST_BASE + 4);
+            tcg_out_ld(s, TCG_TYPE_I32, data_reg, r0, GUEST_BASE);
+        }
+        if (bswap) {
             tcg_out_bswap32(s, data_reg);
-
-            tcg_out_ld(s, TCG_TYPE_I32, data_reg2, r0, GUEST_BASE);
             tcg_out_bswap32(s, data_reg2);
         }
         break;