[newlib-cygwin/main] riscv: add vectorized rawmemchr

[Kito Cheng]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=f18201e63cd2f9e33b90dcac8dd619ff4b1b34b4

commit f18201e63cd2f9e33b90dcac8dd619ff4b1b34b4
Author: Pincheng Wang <pincheng.plct@isrc.iscas.ac.cn>
Date:   Fri May 29 09:19:52 2026 +0800

    riscv: add vectorized rawmemchr
    
    The vector implementation uses m1 register grouping to avoid overly
    lareg fault-only-first loads on large-VLEN implementations. Use
    conditional compilation to fall back to the generic implementation when
    __riscv_vector is not available, maintaining compatibility with
    non-vector RISC-V systems.
    
    Signed-off-by: Pincheng Wang <pincheng.plct@isrc.iscas.ac.cn>

Diff:
---
 newlib/libc/machine/riscv/Makefile.inc    |  2 ++
 newlib/libc/machine/riscv/rawmemchr-asm.S | 27 +++++++++++++++++++++++++++
 newlib/libc/machine/riscv/rawmemchr.c     |  5 +++++
 3 files changed, 34 insertions(+)

diff --git a/newlib/libc/machine/riscv/Makefile.inc b/newlib/libc/machine/riscv/Makefile.inc
index 1fdee8d95..b4c743ff6 100644
--- a/newlib/libc/machine/riscv/Makefile.inc
+++ b/newlib/libc/machine/riscv/Makefile.inc
@@ -15,6 +15,8 @@ libc_a_SOURCES += \
 	%D%/mempcpy.c \
 	%D%/memrchr-asm.S \
 	%D%/memrchr.c \
+	%D%/rawmemchr-asm.S \
+	%D%/rawmemchr.c \
 	%D%/memset.S \
 	%D%/setjmp.S \
 	%D%/stpcpy.c \
diff --git a/newlib/libc/machine/riscv/rawmemchr-asm.S b/newlib/libc/machine/riscv/rawmemchr-asm.S
new file mode 100644
index 000000000..058448716
--- /dev/null
+++ b/newlib/libc/machine/riscv/rawmemchr-asm.S
@@ -0,0 +1,27 @@
+#if defined(__riscv_vector) && !defined(__OPTIMIZE_SIZE__) && !defined(PREFER_SIZE_OVER_SPEED)
+.text
+.global rawmemchr
+.type rawmemchr, @function
+rawmemchr:
+#if __riscv_landing_pad
+  lpad 0
+#endif
+  andi a1, a1, 0xff
+.Lloop:
+  vsetvli t0, zero, e8, m1, ta, ma
+
+  vle8ff.v v0, (a0)
+  vmseq.vx v8, v0, a1
+  vfirst.m a2, v8
+
+  bgez a2, .Lfound
+
+  csrr a3, vl
+  add a0, a0, a3
+  j .Lloop
+
+.Lfound:
+  add a0, a0, a2
+  ret
+.size rawmemchr, .-rawmemchr
+#endif
diff --git a/newlib/libc/machine/riscv/rawmemchr.c b/newlib/libc/machine/riscv/rawmemchr.c
new file mode 100644
index 000000000..00c1da679
--- /dev/null
+++ b/newlib/libc/machine/riscv/rawmemchr.c
@@ -0,0 +1,5 @@
+#if defined(__OPTIMIZE_SIZE__) || defined(PREFER_SIZE_OVER_SPEED) || !defined(__riscv_vector)
+# include "../../string/rawmemchr.c"
+#else
+/* rawmemchr defined in rawmemchr-asm.S */
+#endif