[PULL,09/12] target/i386: use TSTEQ/TSTNE to check flags

Commit Message

Paolo Bonzini March 8, 2024, 2:55 p.m. UTC

The new conditions obviously come in handy when testing individual bits
of EFLAGS, and they make it possible to remove the .mask field of
CCPrepare.

Lowering to shift+and is done by the optimizer if necessary.

Reviewed-by: Richard Henderson <[e-mail]>
Signed-off-by: Paolo Bonzini <[e-mail]>
---
 target/i386/tcg/translate.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

Patch

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index fe9021833e3..63d520e0cba 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -995,8 +995,8 @@  static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
     case CC_OP_EFLAGS:
     case CC_OP_SARB ... CC_OP_SARQ:
         /* CC_SRC & 1 */
-        return (CCPrepare) { .cond = TCG_COND_NE,
-                             .reg = cpu_cc_src, .mask = CC_C };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE,
+                             .reg = cpu_cc_src, .mask = -1, .imm = CC_C };
 
     default:
        /* The need to compute only C from CC_OP_DYNAMIC is important
@@ -1013,8 +1013,8 @@  static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
 static CCPrepare gen_prepare_eflags_p(DisasContext *s, TCGv reg)
 {
     gen_compute_eflags(s);
-    return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                         .mask = CC_P };
+    return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                         .mask = -1, .imm = CC_P };
 }
 
 /* compute eflags.S to reg */
@@ -1028,8 +1028,8 @@  static CCPrepare gen_prepare_eflags_s(DisasContext *s, TCGv reg)
     case CC_OP_ADCX:
     case CC_OP_ADOX:
     case CC_OP_ADCOX:
-        return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                             .mask = CC_S };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                             .mask = -1, .imm = CC_S };
     case CC_OP_CLR:
     case CC_OP_POPCNT:
         return (CCPrepare) { .cond = TCG_COND_NEVER, .mask = -1 };
@@ -1057,8 +1057,8 @@  static CCPrepare gen_prepare_eflags_o(DisasContext *s, TCGv reg)
                              .reg = cpu_cc_src, .mask = -1 };
     default:
         gen_compute_eflags(s);
-        return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                             .mask = CC_O };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                             .mask = -1, .imm = CC_O };
     }
 }
 
@@ -1073,8 +1073,8 @@  static CCPrepare gen_prepare_eflags_z(DisasContext *s, TCGv reg)
     case CC_OP_ADCX:
     case CC_OP_ADOX:
     case CC_OP_ADCOX:
-        return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                             .mask = CC_Z };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                             .mask = -1, .imm = CC_Z };
     case CC_OP_CLR:
         return (CCPrepare) { .cond = TCG_COND_ALWAYS, .mask = -1 };
     case CC_OP_POPCNT:
@@ -1152,8 +1152,8 @@  static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
             break;
         case JCC_BE:
             gen_compute_eflags(s);
-            cc = (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                               .mask = CC_Z | CC_C };
+            cc = (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                               .mask = -1, .imm = CC_Z | CC_C };
             break;
         case JCC_S:
             cc = gen_prepare_eflags_s(s, reg);
@@ -1167,8 +1167,8 @@  static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
                 reg = s->tmp0;
             }
             tcg_gen_addi_tl(reg, cpu_cc_src, CC_O - CC_S);
-            cc = (CCPrepare) { .cond = TCG_COND_NE, .reg = reg,
-                               .mask = CC_O };
+            cc = (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = reg,
+                               .mask = -1, .imm = CC_O };
             break;
         default:
         case JCC_LE:
@@ -1177,8 +1177,8 @@  static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
                 reg = s->tmp0;
             }
             tcg_gen_addi_tl(reg, cpu_cc_src, CC_O - CC_S);
-            cc = (CCPrepare) { .cond = TCG_COND_NE, .reg = reg,
-                               .mask = CC_O | CC_Z };
+            cc = (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = reg,
+                               .mask = -1, .imm = CC_O | CC_Z };
             break;
         }
         break;