Duplicated jump/branch instructions

Code Generation Common Infrastructure
1

There is some simple code that takes the if, transforms it to a switch and then produces duplicate ja (for x86 for example, also confirmed for RISC-V) instructions.

void foo(unsigned short x, int* res) {
    if ( (x <= 13) && (x == 9 || x == 10 || x == 13)) {
        *res +=5;
    }
}

The IR looks fine:

define dso_local void @foo(i16 noundef zeroext %x, ptr nocapture noundef %res) local_unnamed_addr #0 {
entry:
  %cmp = icmp ult i16 %x, 14
  br i1 %cmp, label %land.lhs.true, label %if.end

land.lhs.true:                                    ; preds = %entry
  switch i16 %x, label %if.end [
    i16 13, label %if.then
    i16 10, label %if.then
    i16 9, label %if.then
  ]

if.then:                                          ; preds = %land.lhs.true, %land.lhs.true, %land.lhs.true
  %0 = load i32, ptr %res, align 4, !tbaa !5
  %add = add nsw i32 %0, 5
  store i32 %add, ptr %res, align 4, !tbaa !5
  br label %if.end

if.end:                                           ; preds = %land.lhs.true, %if.then, %entry
  ret void
}

And the resulting asm:

        .text
        .file   "test.c"
        .globl  foo                             # -- Begin function foo
        .p2align        4, 0x90
        .type   foo,@function
foo:                                    # @foo
        .cfi_startproc
# %bb.0:                                # %entry
        cmpw    $13, %di
        ja      .LBB0_4
# %bb.1:                                # %land.lhs.true
        ja      .LBB0_4
# %bb.2:                                # %land.lhs.true
        movzwl  %di, %eax
        movl    $9728, %ecx                     # imm = 0x2600
        btl     %eax, %ecx
        jae     .LBB0_4
# %bb.3:                                # %if.then
        addl    $5, (%rsi)
.LBB0_4:                                # %if.end
        retq
.Lfunc_end0:
        .size   foo, .Lfunc_end0-foo
        .cfi_endproc
                                        # -- End function
        .ident  "clang version 17.0.0 (https://github.com/llvm/llvm-project.git 65c0134872c1e298ade176b5c84d86b4a058a85c)"
        .section        ".note.GNU-stack","",@progbits

You can see the ja .LBB0_4 is a duplicate. Not sure where to fix this exactly, there are a few different places.