Souper says:

; Function: fn1
%0:i32 = var 
%1:i32 = lshr 1:i32, %0
%2:i1 = ne 7:i32, %1
cand %2 1:i1

COMMAND: /home/regehr/souper/build/souper -stp-path=/usr/local/bin/stp reduce_455/foo.bc

LLVM says:

define i32 @fn1() #0 {
entry:
  %0 = load i32* @a, align 4, !tbaa !1
  %shr = lshr i32 1, %0
  store i32 %shr, i32* @b, align 4, !tbaa !1
  %not.cmp = icmp ne i32 %shr, 7
  %. = zext i1 %not.cmp to i32
  ret i32 %.
}

COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -c -w -emit-llvm -O3 reduce_455/foo.c -o reduce_455/foo.bc

C source code:

int a, b;
int fn1() {
  b = 1 >> a;
  if (b != 7)
    return 1;
  return 0;
}

x86-64 from LLVM:

fn1:                                    # @fn1
	movb	a(%rip), %cl
	movl	$1, %eax
	shrl	%cl, %eax
	cmpl	$7, %eax
	movl	%eax, b(%rip)
	setne	%al
	movzbl	%al, %eax
	retq

COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -w -O3 reduce_455/foo.c -S -o -

x86-64 from GCC:

fn1:
	movl	a(%rip), %ecx
	movl	$1, %eax
	sarl	%cl, %eax
	movl	%eax, b(%rip)
	movl	$1, %eax
	ret

COMMAND: gcc -w -O3 reduce_455/foo.c -S -o -