diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index 72460349c8d986ba2bfecfb78aec2ca42368cbc5..684058b1da7200de00ecd9ea73653ba59422633d 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -7668,6 +7668,8 @@ aarch64_frob_label (symbolS * sym)
   last_label_seen = sym;
 
   AARCH64_SET_C64 (sym, IS_C64);
+  if (AARCH64_IS_C64 (sym) && S_IS_FUNCTION (sym))
+    *symbol_X_add_number (sym) += 1;
 
   dwarf2_emit_label (sym);
 }
diff --git a/gas/testsuite/gas/aarch64/morello-function-lsb.d b/gas/testsuite/gas/aarch64/morello-function-lsb.d
new file mode 100644
index 0000000000000000000000000000000000000000..919403b0f076c969ced07a2b1aec551204136485
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/morello-function-lsb.d
@@ -0,0 +1,38 @@
+#as: -march=armv8-a+c64
+#objdump: -srt
+
+.*\.o:     file format .*
+
+SYMBOL TABLE:
+0000000000000000 l    d  \.text	0000000000000000 \.text
+0000000000000000 l    d  \.data	0000000000000000 \.data
+0000000000000000 l    d  \.bss	0000000000000000 \.bss
+0000000000000000 l       \.text	0000000000000000 altlabel
+0000000000000064 l       \*ABS\*	0000000000000000 operand
+0000000000000000 l     O \.data	0000000000000010 f\.p
+0000000000000000 g     F \.text	0000000000000013 f
+
+
+RELOCATION RECORDS FOR \[\.text\]:
+OFFSET           TYPE              VALUE 
+0000000000000014 R_AARCH64_ABS32   f-0x0000000000000064
+0000000000000018 R_AARCH64_PREL32  \*ABS\*\+0x000000000000007b
+
+
+RELOCATION RECORDS FOR \[\.data\]:
+OFFSET           TYPE              VALUE 
+0000000000000000 R_MORELLO_CAPINIT  f\+0x000000000000000c
+
+
+Contents of section \.text:
+ 0000 fd7bbf62 fdd3c1c2 01000014 fd7bc122  .*
+ 0010 c053c2c2 00000000 00000000 01000000  .*
+ 0020 ffffffff 00000000 ffffffff 00000000  .*
+ 0030 00000000 ffffffff ffffffff ffffffff  .*
+ 0040 00000000 00000000 ffffffff 00000000  .*
+ 0050 00000000 ffffffff ffffffff ffffffff  .*
+ 0060 00000000 00000000 00000000 ffffffff  .*
+ 0070 ffffffff ffffffff 00000000 00000000  .*
+ 0080 01000000                             .*
+Contents of section \.data:
+ 0000 00000000 00000000 00000000 00000000  .*
diff --git a/gas/testsuite/gas/aarch64/morello-function-lsb.s b/gas/testsuite/gas/aarch64/morello-function-lsb.s
new file mode 100644
index 0000000000000000000000000000000000000000..70ca354698b0fdeb1a2408fa7f505e9e0e07adf1
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/morello-function-lsb.s
@@ -0,0 +1,67 @@
+        .text
+        .globl  f
+        .p2align        2
+        .type   f,@function
+f:
+altlabel:       // This label does not have function type, so will not have the LSB set.
+	stp	c29, c30, [csp, #-32]!
+	mov	c29, csp
+        b       .LBB0_1
+.Ltmp0:
+.LBB0_1:
+	ldp	c29, c30, [csp], #32
+	ret	c30
+.Lfunc_end0:
+	// Check that the LSB is not included in the offset when the symbol `f`
+	// ends up in the relocation.  In that case it's the linkers
+	// responsibility to account for the LSB.
+        .word   f - operand
+	// Check that if we emit a relocation that does not include the symbol
+	// `f` we account for the LSB.
+        .word   operand - f
+	// Use `.word 1` markers so is easier to tell what's going on by a
+	// human.
+	.word   1
+	// Ensure we account for the LSB in other valid expressions.
+	// In the output test we require these to evaluate to true or false,
+	// and for true to be represented as 0xffffffff
+	.word	altlabel != f
+	.word   altlabel >= f
+	.word   altlabel <= f
+	.word	altlabel == f
+	.word   altlabel > f
+	.word   altlabel < f
+	.word	f != altlabel
+	.word   f >= altlabel
+	.word   f <= altlabel
+	.word	f == altlabel
+	.word   f > altlabel
+	.word   f < altlabel
+	.word	f != f
+	.word   f >= f
+	.word   f <= f
+	.word	f == f
+	.word   f > f
+	.word   f < f
+	.word	altlabel != altlabel
+	.word   altlabel >= altlabel
+	.word   altlabel <= altlabel
+	.word	altlabel == altlabel
+	.word   altlabel > altlabel
+	.word   altlabel < altlabel
+        .word   1
+	// Ensure we account for the LSB in the standard .size directive.
+        .size   f, .Lfunc_end0-f
+
+        .type   f.p,@object
+        .data
+        .p2align        4
+f.p:
+	// This is a standard directive form. We need to ensure accounts for
+	// the LSB in the subexpression  ((.Ltmp0+1)-f), since otherwise the
+	// resulting relocation is invalid.
+        .capinit f+((.Ltmp0+1)-f)
+        .xword  0
+        .xword  0
+        .size   f.p, 16
+.set operand, 100