From 6dd2afed55320eef86873531fe05185be750727f Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 19 Oct 2023 18:25:40 +0200
Subject: [PATCH] target/i386: avoid trunc and ext for MULX and RORX

Use _tl operations for 32-bit operands on 32-bit targets, and only go
through trunc and extu ops for 64-bit targets.  While the trunc/ext
ops should be pretty much free after optimization, the optimizer also
does not like having the same temporary used in multiple EBBs.
Therefore it is nicer to not use tmpN* unless necessary.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/emit.c.inc | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
index 98c4c9569e..f5e44117ea 100644
--- a/target/i386/tcg/emit.c.inc
+++ b/target/i386/tcg/emit.c.inc
@@ -1348,7 +1348,8 @@ static void gen_MULX(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode)
 
     /* low part of result in VEX.vvvv, high in MODRM */
     switch (ot) {
-    default:
+    case MO_32:
+#ifdef TARGET_X86_64
         tcg_gen_trunc_tl_i32(s->tmp2_i32, s->T0);
         tcg_gen_trunc_tl_i32(s->tmp3_i32, s->T1);
         tcg_gen_mulu2_i32(s->tmp2_i32, s->tmp3_i32,
@@ -1356,13 +1357,15 @@ static void gen_MULX(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode)
         tcg_gen_extu_i32_tl(cpu_regs[s->vex_v], s->tmp2_i32);
         tcg_gen_extu_i32_tl(s->T0, s->tmp3_i32);
         break;
-#ifdef TARGET_X86_64
+
     case MO_64:
-        tcg_gen_mulu2_i64(cpu_regs[s->vex_v], s->T0, s->T0, s->T1);
-        break;
 #endif
-    }
+        tcg_gen_mulu2_tl(cpu_regs[s->vex_v], s->T0, s->T0, s->T1);
+        break;
 
+    default:
+        g_assert_not_reached();
+    }
 }
 
 static void gen_PALIGNR(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode)
@@ -1765,14 +1768,24 @@ static void gen_PSLLDQ_i(DisasContext *s, CPUX86State *env, X86DecodedInsn *deco
 static void gen_RORX(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode)
 {
     MemOp ot = decode->op[0].ot;
-    int b = decode->immediate;
+    int mask = ot == MO_64 ? 63 : 31;
+    int b = decode->immediate & mask;
 
-    if (ot == MO_64) {
-        tcg_gen_rotri_tl(s->T0, s->T0, b & 63);
-    } else {
+    switch (ot) {
+    case MO_32:
+#ifdef TARGET_X86_64
         tcg_gen_trunc_tl_i32(s->tmp2_i32, s->T0);
-        tcg_gen_rotri_i32(s->tmp2_i32, s->tmp2_i32, b & 31);
+        tcg_gen_rotri_i32(s->tmp2_i32, s->tmp2_i32, b);
         tcg_gen_extu_i32_tl(s->T0, s->tmp2_i32);
+        break;
+
+    case MO_64:
+#endif
+        tcg_gen_rotri_tl(s->T0, s->T0, b);
+        break;
+
+    default:
+        g_assert_not_reached();
     }
 }
 
-- 
2.39.2