LLVM codegen

nicer.ll

; ModuleID = 'nicer.ll'
target datalayout = "e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define i8 @test({ i8*, i64 } %arg, i64 %arg1) unnamed_addr {
"the block":
  %tmp = extractvalue { i8*, i64 } %arg, 1
  %tmp2 = icmp ugt i64 %tmp, %arg1
  br i1 %tmp2, label %exit, label %cond.i

cond.i:                                           ; preds = %"the block"
  tail call void @fail()
  unreachable

exit:                                             ; preds = %"the block"      ; preds = %"the block"
  %tmp7 = extractvalue { i8*, i64 } %arg, 0
  %tmp5 = getelementptr inbounds i8* %tmp7, i64 %arg1
  %tmp6 = load i8* %tmp5, align 1
  ret i8 %tmp6
}

declare void @fail() unnamed_addr noreturn

nicer.s

	.text
	.file	"nicer.ll"
	.globl	test
	.align	16, 0x90
	.type	test,@function
test:                                   # @test
	.cfi_startproc
# BB#0:                                 # %the block
	pushq	%rax
.Ltmp0:
	.cfi_def_cfa_offset 16
	cmpq	%rdx, %rsi
	jbe	.LBB0_2
# BB#1:                                 # %exit
	movb	(%rdi,%rdx), %al
	popq	%rdx
	retq
.LBB0_2:                                # %cond.i
	callq	fail
.Ltmp1:
	.size	test, .Ltmp1-test
	.cfi_endproc


	.section	".note.GNU-stack","",@progbits