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[v3,03/57] tcg/i386: Conditionalize tcg_out_extu_i32_i64

Message ID 20230424054105.1579315-4-richard.henderson@linaro.org
State Superseded
Headers show
Series tcg: Simplify calls to load/store helpers | expand

Commit Message

Richard Henderson April 24, 2023, 5:40 a.m. UTC 
Since TCG_TYPE_I32 values are kept zero-extended in registers, via
omission of the REXW bit, we need not extend if the register matches.
This is already relied upon by qemu_{ld,st}.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/i386/tcg-target.c.inc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Philippe Mathieu-Daudé April 25, 2023, 7:41 p.m. UTC | #1 
On 24/4/23 07:40, Richard Henderson wrote:
> Since TCG_TYPE_I32 values are kept zero-extended in registers, via
> omission of the REXW bit, we need not extend if the register matches.
> This is already relied upon by qemu_{ld,st}.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   tcg/i386/tcg-target.c.inc | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
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Patch

diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index c8e2bf537f..ce87f8fbc9 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -1314,7 +1314,9 @@  static void tcg_out_exts_i32_i64(TCGContext *s, TCGReg dest, TCGReg src)
 
 static void tcg_out_extu_i32_i64(TCGContext *s, TCGReg dest, TCGReg src)
 {
-    tcg_out_ext32u(s, dest, src);
+    if (dest != src) {
+        tcg_out_ext32u(s, dest, src);
+    }
 }
 
 static void tcg_out_extrl_i64_i32(TCGContext *s, TCGReg dest, TCGReg src)