Souper says:
; Function: fn1
%0:i32 = var
%1:i1 = slt %0, 0:i32
%2:i32 = var
%3:i32 = sdiv 1:i32, %2
%4:i1 = slt %3, %0
%5:i1 = and %1, %4
cand %5 0:i1
COMMAND: /home/regehr/souper/build/souper -stp-path=/usr/local/bin/stp reduce_320/foo.bc
LLVM says:
define void @fn1() #0 {
entry:
%0 = load i32* @a, align 4, !tbaa !1
%div = sdiv i32 1, %0
store i32 %div, i32* @d, align 4, !tbaa !1
%1 = load i32* @b, align 4, !tbaa !1
%cmp = icmp slt i32 %1, 0
%cmp1 = icmp slt i32 %div, %1
%cmp1. = and i1 %cmp, %cmp1
%land.ext = zext i1 %cmp1. to i32
store i32 %land.ext, i32* @c, align 4, !tbaa !1
ret void
}
COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -c -w -emit-llvm -O3 reduce_320/foo.c -o reduce_320/foo.bc
C source code:
int a, b, c, d;
void fn1() {
d = 1 / a;
c = b < 0 && d < b;
}
x86-64 from LLVM:
fn1: # @fn1
movl $1, %eax
xorl %edx, %edx
idivl a(%rip)
movl %eax, d(%rip)
movl b(%rip), %ecx
testl %ecx, %ecx
sets %dl
cmpl %ecx, %eax
setl %al
andb %dl, %al
movzbl %al, %eax
movl %eax, c(%rip)
retq
COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -w -O3 reduce_320/foo.c -S -o -
x86-64 from GCC:
fn1:
movl $1, %eax
movl $0, c(%rip)
cltd
idivl a(%rip)
movl %eax, d(%rip)
ret
COMMAND: gcc -w -O3 reduce_320/foo.c -S -o -