Souper says:

; Function: fn1
%0:i32 = var 
%1:i32 = sdiv %0, 0:i32
%2:i1 = ne 0:i32, %1
cand %2 1:i1

COMMAND: /home/regehr/souper/build/souper -stp-path=/usr/local/bin/stp reduce_646/foo.bc

LLVM says:

define void @fn1() #0 {
entry:
  %0 = load i32* @a, align 4, !tbaa !1
  %div = sdiv i32 %0, 0
  %cmp = icmp ne i32 %div, 0
  %conv = zext i1 %cmp to i32
  store i32 %conv, i32* @b, align 4, !tbaa !1
  ret void
}

COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -c -w -emit-llvm -O3 reduce_646/foo.c -o reduce_646/foo.bc

C source code:

int a, b;
void fn1() {
  int c = 0;
  b = a / c != 0;
}

x86-64 from LLVM:

fn1:                                    # @fn1
	movl	a(%rip), %eax
	xorl	%ecx, %ecx
	cltd
	idivl	%ecx
	testl	%eax, %eax
	setne	%al
	movzbl	%al, %eax
	movl	%eax, b(%rip)
	retq

COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -w -O3 reduce_646/foo.c -S -o -

x86-64 from GCC:

fn1:
	movl	a(%rip), %eax
	xorl	%ecx, %ecx
	cltd
	idivl	%ecx
	testl	%eax, %eax
	setne	%al
	movzbl	%al, %eax
	movl	%eax, b(%rip)
	ret

COMMAND: gcc -w -O3 reduce_646/foo.c -S -o -