On compiling the following C code with gcc -Os -S

#include <stdio.h>
extern int condition1(void);
extern int condition2(void);
extern int condition3(void);
int main()
{
	short c;
	if (condition1()) c = 3;
	if (condition2()) c = 4;
	if (condition3()) printf("%ld\n", (long)c);
}


I end up with

	.file	"x.c"
	.text
	.section	.rodata.str1.1,"aMS",@progbits,1
.LC0:
	.string	"%ld\n"
	.section	.text.startup,"ax",@progbits
	.globl	main
	.type	main, @function
main:
.LFB0:
	.cfi_startproc
	pushq	%rbx
	.cfi_def_cfa_offset 16
	.cfi_offset 3, -16
	call	condition1@PLT
	call	condition2@PLT
	cmpl	$1, %eax
	sbbl	%ebx, %ebx
	addl	$4, %ebx
	call	condition3@PLT
	testl	%eax, %eax
	je	.L3
	movswq	%bx, %rsi
	leaq	.LC0(%rip), %rdi
	xorl	%eax, %eax
	call	printf@PLT
.L3:
	xorl	%eax, %eax
	popq	%rbx
	.cfi_def_cfa_offset 8
	ret
	.cfi_endproc
.LFE0:
	.size	main, .-main
	.ident	"GCC: (Debian 8.3.0-6) 8.3.0"
	.section	.note.GNU-stack,"",@progbits


The replication is currently not possible because the GCC optimizer is dumber than it used to be. Here it generates movswq where it is trivially provable that a mov will do. Since right now gcc always generates a movswq on widening operations the replication currently can't happen.