| ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py |
| ; RUN: opt -bdce %s -S | FileCheck %s |
| |
| ; The 'nuw' on the subtract allows us to deduce that %setbit is not demanded. |
| ; But if we change that value to '0', then the 'nuw' is no longer valid. If we don't |
| ; remove the 'nuw', another pass (-instcombine) may make a transform based on an |
| ; that incorrect assumption and we can miscompile: |
| ; https://bugs.llvm.org/show_bug.cgi?id=33695 |
| |
| define i1 @PR33695(i1 %b, i8 %x) { |
| ; CHECK-LABEL: @PR33695( |
| ; CHECK-NEXT: [[LITTLE_NUMBER:%.*]] = zext i1 [[B:%.*]] to i8 |
| ; CHECK-NEXT: [[BIG_NUMBER:%.*]] = shl i8 0, 1 |
| ; CHECK-NEXT: [[SUB:%.*]] = sub i8 [[BIG_NUMBER]], [[LITTLE_NUMBER]] |
| ; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[SUB]] to i1 |
| ; CHECK-NEXT: ret i1 [[TRUNC]] |
| ; |
| %setbit = or i8 %x, 64 |
| %little_number = zext i1 %b to i8 |
| %big_number = shl i8 %setbit, 1 |
| %sub = sub nuw i8 %big_number, %little_number |
| %trunc = trunc i8 %sub to i1 |
| ret i1 %trunc |
| } |
| |
| ; Similar to above, but now with more no-wrap. |
| ; https://bugs.llvm.org/show_bug.cgi?id=34037 |
| |
| define i64 @PR34037(i64 %m, i32 %r, i64 %j, i1 %b, i32 %k, i64 %p) { |
| ; CHECK-LABEL: @PR34037( |
| ; CHECK-NEXT: [[SHL:%.*]] = shl i64 0, 29 |
| ; CHECK-NEXT: [[CONV1:%.*]] = select i1 [[B:%.*]], i64 7, i64 0 |
| ; CHECK-NEXT: [[SUB:%.*]] = sub i64 [[SHL]], [[CONV1]] |
| ; CHECK-NEXT: [[CONV2:%.*]] = zext i32 [[K:%.*]] to i64 |
| ; CHECK-NEXT: [[MUL:%.*]] = mul i64 [[SUB]], [[CONV2]] |
| ; CHECK-NEXT: [[CONV4:%.*]] = and i64 [[P:%.*]], 65535 |
| ; CHECK-NEXT: [[AND5:%.*]] = and i64 [[MUL]], [[CONV4]] |
| ; CHECK-NEXT: ret i64 [[AND5]] |
| ; |
| %conv = zext i32 %r to i64 |
| %and = and i64 %m, %conv |
| %neg = xor i64 %and, 34359738367 |
| %or = or i64 %j, %neg |
| %shl = shl i64 %or, 29 |
| %conv1 = select i1 %b, i64 7, i64 0 |
| %sub = sub nuw nsw i64 %shl, %conv1 |
| %conv2 = zext i32 %k to i64 |
| %mul = mul nsw i64 %sub, %conv2 |
| %conv4 = and i64 %p, 65535 |
| %and5 = and i64 %mul, %conv4 |
| ret i64 %and5 |
| } |
| |
| ; This is a manufactured example based on the 1st test to prove that the |
| ; assumption-killing algorithm stops at the call. Ie, it does not remove |
| ; nsw/nuw from the 'add' because a call demands all bits of its argument. |
| |
| declare i1 @foo(i1) |
| |
| define i1 @poison_on_call_user_is_ok(i1 %b, i8 %x) { |
| ; CHECK-LABEL: @poison_on_call_user_is_ok( |
| ; CHECK-NEXT: [[LITTLE_NUMBER:%.*]] = zext i1 [[B:%.*]] to i8 |
| ; CHECK-NEXT: [[BIG_NUMBER:%.*]] = shl i8 0, 1 |
| ; CHECK-NEXT: [[SUB:%.*]] = sub i8 [[BIG_NUMBER]], [[LITTLE_NUMBER]] |
| ; CHECK-NEXT: [[TRUNC:%.*]] = trunc i8 [[SUB]] to i1 |
| ; CHECK-NEXT: [[CALL_RESULT:%.*]] = call i1 @foo(i1 [[TRUNC]]) |
| ; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw i1 [[CALL_RESULT]], true |
| ; CHECK-NEXT: [[MUL:%.*]] = mul i1 [[TRUNC]], [[ADD]] |
| ; CHECK-NEXT: ret i1 [[MUL]] |
| ; |
| %setbit = or i8 %x, 64 |
| %little_number = zext i1 %b to i8 |
| %big_number = shl i8 %setbit, 1 |
| %sub = sub nuw i8 %big_number, %little_number |
| %trunc = trunc i8 %sub to i1 |
| %call_result = call i1 @foo(i1 %trunc) |
| %add = add nsw nuw i1 %call_result, 1 |
| %mul = mul i1 %trunc, %add |
| ret i1 %mul |
| } |
| |
| |
| ; We were asserting that all users of a trivialized integer-type instruction were |
| ; also integer-typed, but that's too strong. The alloca has a pointer-type result. |
| |
| define void @PR34179(i32* %a) { |
| ; CHECK-LABEL: @PR34179( |
| ; CHECK-NEXT: [[T0:%.*]] = load volatile i32, i32* [[A:%.*]] |
| ; CHECK-NEXT: ret void |
| ; |
| %t0 = load volatile i32, i32* %a |
| %vla = alloca i32, i32 %t0 |
| ret void |
| } |
| |