diff mbox series

[v2,10/35] tcg/aarch64: Generate CBNZ for TSTNE of UINT32_MAX

Message ID 20231028194522.245170-11-richard.henderson@linaro.org
State Superseded
Headers show
Series tcg: Introduce TCG_COND_TST{EQ,NE} | expand

Commit Message

Richard Henderson Oct. 28, 2023, 7:44 p.m. UTC 
... and the inverse, CBZ for TSTEQ.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/aarch64/tcg-target.c.inc | 8 ++++++++
 1 file changed, 8 insertions(+)
diff mbox series

Patch

diff --git a/tcg/aarch64/tcg-target.c.inc b/tcg/aarch64/tcg-target.c.inc
index 55225313ad..0c98c48f68 100644
--- a/tcg/aarch64/tcg-target.c.inc
+++ b/tcg/aarch64/tcg-target.c.inc
@@ -1453,6 +1453,7 @@  static void tcg_out_brcond(TCGContext *s, TCGType ext, TCGCond c, TCGArg a,
         break;
     case TCG_COND_LT:
     case TCG_COND_GE:
+        /* cmp xN,0; b.mi L -> tbnz xN,63,L */
         if (b_const && b == 0) {
             c = (c == TCG_COND_LT ? TCG_COND_TSTNE : TCG_COND_TSTEQ);
             tbit = ext ? 63 : 31;
@@ -1461,6 +1462,13 @@  static void tcg_out_brcond(TCGContext *s, TCGType ext, TCGCond c, TCGArg a,
         break;
     case TCG_COND_TSTEQ:
     case TCG_COND_TSTNE:
+        /* tst xN,0xffffffff; b.ne L -> cbnz wN,L */
+        if (b_const && b == UINT32_MAX) {
+            ext = TCG_TYPE_I32;
+            need_cmp = false;
+            break;
+        }
+        /* tst xN,1<<B; b.ne L -> tbnz xN,B,L */
         if (b_const && is_power_of_2(b)) {
             tbit = ctz64(b);
             need_cmp = false;