On 12/6/25 12:24, WANG Xuerui wrote:
From: WANG Xuerui <[email protected]>
Support for TCGCond's in loongarch64 cmp_vec codegen is not uniform: NE
is not supported at all and will trip over assertions, and legalization
(currently just operand-swapping) is not done for reg-imm comparisons.
Since the TCG middle-end will not legalize the comparison conditions for
us, we have to do it ourselves like other targets.
Because EQ/LT/LTU/LE/LEU are natively supported, we only have to keep
the current operand swapping treatment for GT/GTU/GE/GEU but ensure it
is done for both reg-reg and reg-imm cases, and use a bitwise NOT to
help legalize NE.
While at it, lift the cmp_vec handling to own function to make it easier
for readers.
Fixes: d8b6fa593d2d ("tcg/loongarch64: Lower cmp_vec to vseq/vsle/vslt")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3237
Cc: Richard Henderson <[email protected]>
Cc: Philippe Mathieu-Daudé <[email protected]>
Reported-by: xtex <[email protected]>
Signed-off-by: WANG Xuerui <[email protected]>
---
tcg/loongarch64/tcg-target.c.inc | 119 +++++++++++++++++++------------
1 file changed, 75 insertions(+), 44 deletions(-)
diff --git a/tcg/loongarch64/tcg-target.c.inc b/tcg/loongarch64/tcg-target.c.inc
index 10c69211ac5..1a243a57beb 100644
--- a/tcg/loongarch64/tcg-target.c.inc
+++ b/tcg/loongarch64/tcg-target.c.inc
@@ -2179,15 +2179,38 @@ static void tcg_out_addsub_vec(TCGContext *s, bool
lasx, unsigned vece,
tcg_out32(s, encode_vdvjvk_insn(insn, a0, a1, a2));
}
-static void tcg_out_vec_op(TCGContext *s, TCGOpcode opc,
- unsigned vecl, unsigned vece,
- const TCGArg args[TCG_MAX_OP_ARGS],
- const int const_args[TCG_MAX_OP_ARGS])
+static void tcg_out_cmp_vec(TCGContext *s, bool lasx, unsigned vece,
+ TCGArg a0, TCGArg a1, TCGArg a2,
+ bool a2_is_const, TCGCond cond)
{
- TCGType type = vecl + TCG_TYPE_V64;
- bool lasx = type == TCG_TYPE_V256;
- TCGArg a0, a1, a2, a3;
LoongArchInsn insn;
+ bool need_invert = false;
+
+ switch (cond) {
+ case TCG_COND_EQ:
+ case TCG_COND_LE:
+ case TCG_COND_LEU:
+ case TCG_COND_LT:
+ case TCG_COND_LTU:
+ /* These are directly expressible. */
+ break;
+ case TCG_COND_NE:
+ need_invert = true;
+ cond = TCG_COND_EQ;
+ break;
+ case TCG_COND_GE:
+ case TCG_COND_GEU:
+ case TCG_COND_GT:
+ case TCG_COND_GTU:
+ {
+ TCGArg t;
+ t = a1, a1 = a2, a2 = t;
+ cond = tcg_swap_cond(cond);
+ break;
+ }
You can't just swap if a2_is_const.
You can get better results by using tcg_expand_vec_op() to transform the
comparison early.
You probably want to do something like s390x, where you have a helper that transforms the
comparision but without the inversion for NE, and then applies the inversion for
INDEX_op_cmp_vec and swaps operands for INDEX_op_cmpsel_vec.
r~
