From: Richard Henderson <richard.henderson@linaro.org>
Date: Wed, 27 Aug 2025 10:33:27 +0000 (+1000)
Subject: tcg/i386: Expand sari of bits-1 as pcmpgt
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=26c41cc4a3d998caa700407a27e18755a6e1895c;p=thirdparty%2Fqemu.git

tcg/i386: Expand sari of bits-1 as pcmpgt

Expand arithmetic right shift of bits-1 as a comparison vs 0.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---

diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index 088c6c9264b..4cd5d4276c9 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -4357,6 +4357,12 @@ static void expand_vec_sari(TCGType type, unsigned vece,
 {
     TCGv_vec t1, t2;
 
+    if (imm >= (8 << vece) - 1) {
+        tcg_gen_cmp_vec(TCG_COND_LT, vece, v0, v1,
+                        tcg_constant_vec(type, MO_64, 0));
+        return;
+    }
+
     switch (vece) {
     case MO_8:
         /* Unpack to 16-bit, shift, and repack.  */