No need for a full comparison; xor produces non-zero bits
for QC just fine.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/tcg/gengvec.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/target/arm/tcg/gengvec.c b/target/arm/tcg/gengvec.c
index 22c9d17dce..bfe6885a01 100644
--- a/target/arm/tcg/gengvec.c
+++ b/target/arm/tcg/gengvec.c
@@ -1217,21 +1217,21 @@ void gen_gvec_sshl(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
     tcg_gen_gvec_3(rd_ofs, rn_ofs, rm_ofs, opr_sz, max_sz, &ops[vece]);
 }
 
-static void gen_uqadd_vec(unsigned vece, TCGv_vec t, TCGv_vec sat,
+static void gen_uqadd_vec(unsigned vece, TCGv_vec t, TCGv_vec qc,
                           TCGv_vec a, TCGv_vec b)
 {
     TCGv_vec x = tcg_temp_new_vec_matching(t);
     tcg_gen_add_vec(vece, x, a, b);
     tcg_gen_usadd_vec(vece, t, a, b);
-    tcg_gen_cmp_vec(TCG_COND_NE, vece, x, x, t);
-    tcg_gen_or_vec(vece, sat, sat, x);
+    tcg_gen_xor_vec(vece, x, x, t);
+    tcg_gen_or_vec(vece, qc, qc, x);
 }
 
 void gen_gvec_uqadd_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                        uint32_t rm_ofs, uint32_t opr_sz, uint32_t max_sz)
 {
     static const TCGOpcode vecop_list[] = {
-        INDEX_op_usadd_vec, INDEX_op_cmp_vec, INDEX_op_add_vec, 0
+        INDEX_op_usadd_vec, INDEX_op_add_vec, 0
     };
     static const GVecGen4 ops[4] = {
         { .fniv = gen_uqadd_vec,
@@ -1259,21 +1259,21 @@ void gen_gvec_uqadd_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                    rn_ofs, rm_ofs, opr_sz, max_sz, &ops[vece]);
 }
 
-static void gen_sqadd_vec(unsigned vece, TCGv_vec t, TCGv_vec sat,
+static void gen_sqadd_vec(unsigned vece, TCGv_vec t, TCGv_vec qc,
                           TCGv_vec a, TCGv_vec b)
 {
     TCGv_vec x = tcg_temp_new_vec_matching(t);
     tcg_gen_add_vec(vece, x, a, b);
     tcg_gen_ssadd_vec(vece, t, a, b);
-    tcg_gen_cmp_vec(TCG_COND_NE, vece, x, x, t);
-    tcg_gen_or_vec(vece, sat, sat, x);
+    tcg_gen_xor_vec(vece, x, x, t);
+    tcg_gen_or_vec(vece, qc, qc, x);
 }
 
 void gen_gvec_sqadd_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                        uint32_t rm_ofs, uint32_t opr_sz, uint32_t max_sz)
 {
     static const TCGOpcode vecop_list[] = {
-        INDEX_op_ssadd_vec, INDEX_op_cmp_vec, INDEX_op_add_vec, 0
+        INDEX_op_ssadd_vec, INDEX_op_add_vec, 0
     };
     static const GVecGen4 ops[4] = {
         { .fniv = gen_sqadd_vec,
@@ -1301,21 +1301,21 @@ void gen_gvec_sqadd_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                    rn_ofs, rm_ofs, opr_sz, max_sz, &ops[vece]);
 }
 
-static void gen_uqsub_vec(unsigned vece, TCGv_vec t, TCGv_vec sat,
+static void gen_uqsub_vec(unsigned vece, TCGv_vec t, TCGv_vec qc,
                           TCGv_vec a, TCGv_vec b)
 {
     TCGv_vec x = tcg_temp_new_vec_matching(t);
     tcg_gen_sub_vec(vece, x, a, b);
     tcg_gen_ussub_vec(vece, t, a, b);
-    tcg_gen_cmp_vec(TCG_COND_NE, vece, x, x, t);
-    tcg_gen_or_vec(vece, sat, sat, x);
+    tcg_gen_xor_vec(vece, x, x, t);
+    tcg_gen_or_vec(vece, qc, qc, x);
 }
 
 void gen_gvec_uqsub_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                        uint32_t rm_ofs, uint32_t opr_sz, uint32_t max_sz)
 {
     static const TCGOpcode vecop_list[] = {
-        INDEX_op_ussub_vec, INDEX_op_cmp_vec, INDEX_op_sub_vec, 0
+        INDEX_op_ussub_vec, INDEX_op_sub_vec, 0
     };
     static const GVecGen4 ops[4] = {
         { .fniv = gen_uqsub_vec,
@@ -1343,21 +1343,21 @@ void gen_gvec_uqsub_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                    rn_ofs, rm_ofs, opr_sz, max_sz, &ops[vece]);
 }
 
-static void gen_sqsub_vec(unsigned vece, TCGv_vec t, TCGv_vec sat,
+static void gen_sqsub_vec(unsigned vece, TCGv_vec t, TCGv_vec qc,
                           TCGv_vec a, TCGv_vec b)
 {
     TCGv_vec x = tcg_temp_new_vec_matching(t);
     tcg_gen_sub_vec(vece, x, a, b);
     tcg_gen_sssub_vec(vece, t, a, b);
-    tcg_gen_cmp_vec(TCG_COND_NE, vece, x, x, t);
-    tcg_gen_or_vec(vece, sat, sat, x);
+    tcg_gen_xor_vec(vece, x, x, t);
+    tcg_gen_or_vec(vece, qc, qc, x);
 }
 
 void gen_gvec_sqsub_qc(unsigned vece, uint32_t rd_ofs, uint32_t rn_ofs,
                        uint32_t rm_ofs, uint32_t opr_sz, uint32_t max_sz)
 {
     static const TCGOpcode vecop_list[] = {
-        INDEX_op_sssub_vec, INDEX_op_cmp_vec, INDEX_op_sub_vec, 0
+        INDEX_op_sssub_vec, INDEX_op_sub_vec, 0
     };
     static const GVecGen4 ops[4] = {
         { .fniv = gen_sqsub_vec,
-- 
2.34.1

On Sat, 25 May 2024 at 00:28, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> No need for a full comparison; xor produces non-zero bits
> for QC just fine.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM