[PATCH v1] rs6000: unnecessary clear after vctzlsbb in vec_first_match_or_eos_index

[Ajit Agarwal via Gcc-patches]

This patch removes zero extension from vctzlsbb as it already zero extends.
Bootstrapped and regtested on powerpc64-linux-gnu.

Thanks & Regards
Ajit

rs6000: unnecessary clear after vctzlsbb in vec_first_match_or_eos_index

For rs6000 target we dont need zero_extend after vctzlsbb as vctzlsbb
already zero extend.

2023-09-12  Ajit Kumar Agarwal  <aagar...@linux.ibm.com>

gcc/ChangeLog:

        * config/rs6000/vsx.md (vctzlsbb_zext_<mode>): New define_insn.

gcc/testsuite/ChangeLog:

        * g++.target/powerpc/altivec-19.C: New testcase.
---
 gcc/config/rs6000/vsx.md                      | 17 ++++++++++++++---
 gcc/testsuite/g++.target/powerpc/altivec-19.C | 10 ++++++++++
 2 files changed, 24 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.target/powerpc/altivec-19.C

diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index 19abfeb565a..42379409e5f 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -5846,11 +5846,22 @@
   [(set_attr "type" "vecsimple")])
 
 ;; Vector Count Trailing Zero Least-Significant Bits Byte
-(define_insn "vctzlsbb_<mode>"
-  [(set (match_operand:SI 0 "register_operand" "=r")
+(define_insn "vctzlsbb_zext_<mode>"
+  [(set (match_operand:DI 0 "register_operand" "=r")
+       (zero_extend:DI
        (unspec:SI
         [(match_operand:VSX_EXTRACT_I 1 "altivec_register_operand" "v")]
-        UNSPEC_VCTZLSBB))]
+        UNSPEC_VCTZLSBB)))]
+  "TARGET_P9_VECTOR"
+  "vctzlsbb %0,%1"
+  [(set_attr "type" "vecsimple")])
+
+;; Vector Count Trailing Zero Least-Significant Bits Byte
+(define_insn "vctzlsbb_<mode>"
+  [(set (match_operand:SI 0 "register_operand" "=r")
+        (unspec:SI
+         [(match_operand:VSX_EXTRACT_I 1 "altivec_register_operand" "v")]
+         UNSPEC_VCTZLSBB))]
   "TARGET_P9_VECTOR"
   "vctzlsbb %0,%1"
   [(set_attr "type" "vecsimple")])
diff --git a/gcc/testsuite/g++.target/powerpc/altivec-19.C 
b/gcc/testsuite/g++.target/powerpc/altivec-19.C
new file mode 100644
index 00000000000..e49e5076af8
--- /dev/null
+++ b/gcc/testsuite/g++.target/powerpc/altivec-19.C
@@ -0,0 +1,10 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-mdejagnu-cpu=power9 -O2 " } */ 
+
+#include <altivec.h>
+
+unsigned int foo (vector unsigned char a, vector unsigned char b) {
+  return vec_first_match_or_eos_index (a, b);
+}
+/* { dg-final { scan-assembler-not {\mrldicl\M} } } */
-- 
2.39.3