[v2] tcg: Introduce TCG_COND_TST{EQ,NE}

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

Richard Henderson posted 35 patches 1 year, 1 month ago

Diff against v1 v3
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Maintainers: Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Laurent Vivier <laurent@vivier.eu>, WANG Xuerui <git@xen0n.name>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Aurelien Jarno <aurelien@aurel32.net>, Huacai Chen <chenhuacai@kernel.org>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Aleksandar Rikalo <aleksandar.rikalo@syrmia.com>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <Alistair.Francis@wdc.com>, Stefan Weil <sw@weilnetz.de>

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

Posted by Richard Henderson 1 year, 1 month ago

... 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 --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;
-- 
2.34.1