diff --git a/gcc/config/riscv/bitmanip.md b/gcc/config/riscv/bitmanip.md
index a9c8275fca7b82381ae625ba5abc0c29155595a1..92bcdc30fe47621a6fc50d73c59ff4c599252540 100644
--- a/gcc/config/riscv/bitmanip.md
+++ b/gcc/config/riscv/bitmanip.md
@@ -290,7 +290,7 @@
 (define_insn "*zero_extendhi<GPR:mode>2_bitmanip"
   [(set (match_operand:GPR 0 "register_operand" "=r,r")
         (zero_extend:GPR (match_operand:HI 1 "nonimmediate_operand" "r,m")))]
-  "TARGET_ZBB"
+  "TARGET_ZBB && !TARGET_XTHEADMEMIDX"
   "@
    zext.h\t%0,%1
    lhu\t%0,%1"
@@ -301,7 +301,7 @@
   [(set (match_operand:SUPERQI   0 "register_operand"     "=r,r")
 	(sign_extend:SUPERQI
 	    (match_operand:SHORT 1 "nonimmediate_operand" " r,m")))]
-  "TARGET_ZBB"
+  "TARGET_ZBB && !TARGET_XTHEADMEMIDX"
   "@
    sext.<SHORT:size>\t%0,%1
    l<SHORT:size>\t%0,%1"
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadfmemidx-uindex-zbb.c b/gcc/testsuite/gcc.target/riscv/xtheadfmemidx-uindex-zbb.c
new file mode 100644
index 0000000000000000000000000000000000000000..a05bc220cbad0b1d1416255fab4ae5b07ccf0886
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadfmemidx-uindex-zbb.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-Og" } } */
+/* { dg-options "-march=rv64gc_zbb_xtheadmemidx -mabi=lp64d" { target { rv64 } } } */
+/* { dg-options "-march=rv32imafc_zbb_xtheadmemidx -mabi=ilp32f" { target { rv32 } } } */
+
+const unsigned char *
+read_uleb128(const unsigned char *p, unsigned long *val)
+{
+  unsigned int shift = 0;
+  unsigned char byte;
+  unsigned long result;
+
+  result = 0;
+  do
+  {
+    byte = *p++;
+    result |= ((unsigned long)byte & 0x7f) << shift;
+    shift += 7;
+  } while (byte & 0x80);
+
+  *val = result;
+  return p;
+}
+
+void test(const unsigned char *p, unsigned long utmp)
+{
+  p = read_uleb128(p, &utmp);
+}
+
+/* { dg-final { scan-assembler-not {\mlb\ta[0-9],\(a[0-9]\),1,0\M} } } */