[Qemu-devel] [6798] tcg: optimize nor(X, Y, Y), used on PPC for not(X, Y)

[Qemu-devel] [6798] tcg: optimize nor(X, Y, Y), used on PPC for not(X, Y)

[Aurelien Jarno]

Revision: 6798
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6798
Author:   aurel32
Date:     2009-03-09 22:35:22 +0000 (Mon, 09 Mar 2009)
Log Message:
-----------
tcg: optimize nor(X, Y, Y), used on PPC for not(X, Y)

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

Modified Paths:
--------------
    trunk/tcg/tcg-op.h

Modified: trunk/tcg/tcg-op.h
===================================================================
--- trunk/tcg/tcg-op.h	2009-03-09 22:35:13 UTC (rev 6797)
+++ trunk/tcg/tcg-op.h	2009-03-09 22:35:22 UTC (rev 6798)
@@ -1545,20 +1545,28 @@
 
 static inline void tcg_gen_nor_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)
 {
-    TCGv_i32 t0;
-    t0 = tcg_temp_new_i32();
-    tcg_gen_or_i32(t0, arg1, arg2);
-    tcg_gen_not_i32(ret, t0);
-    tcg_temp_free_i32(t0);
+    if (GET_TCGV_I32(arg1) != GET_TCGV_I32(arg2)) {
+        TCGv_i32 t0;
+        t0 = tcg_temp_new_i32();
+        tcg_gen_or_i32(t0, arg1, arg2);
+        tcg_gen_not_i32(ret, t0);
+        tcg_temp_free_i32(t0);
+    } else {
+        tcg_gen_not_i32(ret, arg1);
+    }
 }
 
 static inline void tcg_gen_nor_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    TCGv_i64 t0;
-    t0 = tcg_temp_new_i64();
-    tcg_gen_or_i64(t0, arg1, arg2);
-    tcg_gen_not_i64(ret, t0);
-    tcg_temp_free_i64(t0);
+    if (GET_TCGV_I64(arg1) != GET_TCGV_I64(arg2)) {
+        TCGv_i64 t0;
+        t0 = tcg_temp_new_i64();
+        tcg_gen_or_i64(t0, arg1, arg2);
+        tcg_gen_not_i64(ret, t0);
+        tcg_temp_free_i64(t0);
+    } else {
+        tcg_gen_not_i64(ret, arg1);
+    }
 }
 
 static inline void tcg_gen_orc_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)

Re: [Qemu-devel] [6798] tcg: optimize nor(X, Y, Y), used on PPC for not(X, Y)

[Paul Brook]

On Monday 09 March 2009, Aurelien Jarno wrote:
> +    if (GET_TCGV_I32(arg1) != GET_TCGV_I32(arg2)) {

This should be TCGV_EQUAL_I32[1]. IMHO any use of GET_TCGV outside of tcg/ is 
wrong[2].

> +    if (GET_TCGV_I64(arg1) != GET_TCGV_I64(arg2)) {

Likewise.

Paul

[1] It doesn't exist yet, but TCGV_EQUAL does.
[2] target-arm/translate.c is the chief offender. My excuse is that I wrote 
that code before tcg_temp_free existed.