Souper says:
; Function: fn1
%0:i8 = var
%1:i32 = sext %0
%2:i32 = or 1:i32, %1
%3:i1 = eq 217:i32, %2
cand %3 0:i1
COMMAND: /home/regehr/souper/build/souper -stp-path=/usr/local/bin/stp reduce_157/foo.bc
LLVM says:
define void @fn1(i32 %p1) #0 {
entry:
%xor1 = or i32 %p1, 1
%cmp2 = icmp eq i32 %xor1, 217
br i1 %cmp2, label %if.then, label %if.end.lr.ph
if.end.lr.ph: ; preds = %entry
%0 = load i8* @a, align 1, !tbaa !1
%conv = sext i8 %0 to i32
%xor = or i32 %conv, 1
%cmp = icmp eq i32 %xor, 217
br i1 %cmp, label %if.then, label %if.end.preheader
if.end.preheader: ; preds = %if.end.lr.ph
br label %if.end
if.then: ; preds = %if.end.lr.ph, %entry
store i8 0, i8* @a, align 1, !tbaa !1
br label %for.cond
for.cond: ; preds = %for.cond, %if.then
br label %for.cond
if.end: ; preds = %if.end.preheader, %if.end
br label %if.end
}
COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -c -w -emit-llvm -O3 reduce_157/foo.c -o reduce_157/foo.bc
C source code:
char a;
void fn1(p1) {
if ((1 | p1 ^ 216) == 1) {
a = 0;
for (;;)
;
}
fn1(a);
}
x86-64 from LLVM:
fn1: # @fn1
orl $1, %edi
cmpl $217, %edi
je .LBB0_2
movsbl a(%rip), %eax
orl $1, %eax
cmpl $217, %eax
jne .LBB0_4
.LBB0_2: # %if.then
movb $0, a(%rip)
.LBB0_3: # %for.cond
jmp .LBB0_3
.LBB0_4: # %if.end
jmp .LBB0_4
COMMAND: /home/regehr/souper/third_party/llvm/Debug/bin/clang -w -O3 reduce_157/foo.c -S -o -
x86-64 from GCC:
fn1:
xorb $-40, %dil
orl $1, %edi
cmpl $1, %edi
je .L4
movsbl a(%rip), %eax
xorb $-40, %al
orl $1, %eax
cmpl $1, %eax
je .L4
.L5:
jmp .L5
.L4:
movb $0, a(%rip)
.L3:
jmp .L3
COMMAND: gcc -w -O3 reduce_157/foo.c -S -o -