Souper says:
; Function: fn1
%0:i32 = var
%1:i32 = mul 4294967294:i32, %0
%2:i1 = eq 1:i32, %1
cand %2 0:i1
COMMAND: /home/regehr/souper/build/souper -stp-path=/usr/local/bin/stp reduce_6/foo.bc
LLVM says:
define void @fn1() #0 {
entry:
%0 = load i32* @a, align 4, !tbaa !1
%mul = mul nsw i32 %0, -2
%cmp = icmp eq i32 %mul, 1
%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_6/foo.c -o reduce_6/foo.bc
C source code:
int a, b;
void fn1() { b = a * ~1 == 1; }
x86-64 from LLVM:
fn1: # @fn1
movl a(%rip), %eax
addl %eax, %eax
cmpl $-1, %eax
sete %al
movzbl %al, %eax
movl %eax, b(%rip)
retq
COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -w -O3 reduce_6/foo.c -S -o -
x86-64 from GCC:
fn1:
movl $0, b(%rip)
ret
COMMAND: gcc -w -O3 reduce_6/foo.c -S -o -