; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt < %s -instcombine -S | FileCheck %s declare void @use8(i8) declare void @use1(i1) declare void @llvm.assume(i1) ; Here we don't know that at least one of the values being added is non-zero define i1 @t0_bad(i8 %base, i8 %offset) { ; CHECK-LABEL: @t0_bad( ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 ; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]] ; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]] ; CHECK-NEXT: ret i1 [[R]] ; %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t0_bad_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t0_bad_logical( ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 ; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]] ; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]] ; CHECK-NEXT: ret i1 [[R]] ; %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } ; Ok, base is non-zero. define i1 @t1(i8 %base, i8 %offset) { ; CHECK-LABEL: @t1( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t1_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t1_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } ; Ok, offset is non-zero. define i1 @t2(i8 %base, i8 %offset) { ; CHECK-LABEL: @t2( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[OFFSET:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[OFFSET]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[BASE]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %offset, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t2_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t2_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[OFFSET:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE:%.*]], [[OFFSET]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[OFFSET]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[BASE]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %offset, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } ; We need to produce extra instruction, so one of icmp's must go away. define i1 @t3_oneuse0(i8 %base, i8 %offset) { ; CHECK-LABEL: @t3_oneuse0( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 ; CHECK-NEXT: call void @use1(i1 [[NOT_NULL]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 call void @use1(i1 %not_null) %no_underflow = icmp ult i8 %adjusted, %base %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t3_oneuse0_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t3_oneuse0_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 ; CHECK-NEXT: call void @use1(i1 [[NOT_NULL]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 call void @use1(i1 %not_null) %no_underflow = icmp ult i8 %adjusted, %base %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } define i1 @t4_oneuse1(i8 %base, i8 %offset) { ; CHECK-LABEL: @t4_oneuse1( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]] ; CHECK-NEXT: call void @use1(i1 [[NO_UNDERFLOW]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base call void @use1(i1 %no_underflow) %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t4_oneuse1_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t4_oneuse1_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]] ; CHECK-NEXT: call void @use1(i1 [[NO_UNDERFLOW]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base call void @use1(i1 %no_underflow) %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } define i1 @t5_oneuse2_bad(i8 %base, i8 %offset) { ; CHECK-LABEL: @t5_oneuse2_bad( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 ; CHECK-NEXT: call void @use1(i1 [[NOT_NULL]]) ; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]] ; CHECK-NEXT: call void @use1(i1 [[NO_UNDERFLOW]]) ; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]] ; CHECK-NEXT: ret i1 [[R]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 call void @use1(i1 %not_null) %no_underflow = icmp ult i8 %adjusted, %base call void @use1(i1 %no_underflow) %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t5_oneuse2_bad_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t5_oneuse2_bad_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[NOT_NULL:%.*]] = icmp ne i8 [[ADJUSTED]], 0 ; CHECK-NEXT: call void @use1(i1 [[NOT_NULL]]) ; CHECK-NEXT: [[NO_UNDERFLOW:%.*]] = icmp ult i8 [[ADJUSTED]], [[BASE]] ; CHECK-NEXT: call void @use1(i1 [[NO_UNDERFLOW]]) ; CHECK-NEXT: [[R:%.*]] = and i1 [[NOT_NULL]], [[NO_UNDERFLOW]] ; CHECK-NEXT: ret i1 [[R]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 call void @use1(i1 %not_null) %no_underflow = icmp ult i8 %adjusted, %base call void @use1(i1 %no_underflow) %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } define i1 @t6_commutativity0(i8 %base, i8 %offset) { ; CHECK-LABEL: @t6_commutativity0( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = and i1 %no_underflow, %not_null ; swapped ret i1 %r } define i1 @t6_commutativity0_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t6_commutativity0_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %base %r = select i1 %no_underflow, i1 %not_null, i1 false ; swapped ret i1 %r } define i1 @t7_commutativity1(i8 %base, i8 %offset) { ; CHECK-LABEL: @t7_commutativity1( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ugt i8 %base, %adjusted ; swapped %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t7_commutativity1_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t7_commutativity1_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ugt i8 %base, %adjusted ; swapped %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r } define i1 @t7_commutativity3(i8 %base, i8 %offset) { ; CHECK-LABEL: @t7_commutativity3( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ugt i8 %base, %adjusted ; swapped %r = and i1 %no_underflow, %not_null ; swapped ret i1 %r } define i1 @t7_commutativity3_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t7_commutativity3_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ugt i8 %base, %adjusted ; swapped %r = select i1 %no_underflow, i1 %not_null, i1 false ; swapped ret i1 %r } ; We could have the opposite question, did we get null or overflow happened? define i1 @t8(i8 %base, i8 %offset) { ; CHECK-LABEL: @t8( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp uge i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp eq i8 %adjusted, 0 %no_underflow = icmp uge i8 %adjusted, %base %r = or i1 %not_null, %no_underflow ret i1 %r } define i1 @t8_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t8_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp uge i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp eq i8 %adjusted, 0 %no_underflow = icmp uge i8 %adjusted, %base %r = select i1 %not_null, i1 true, i1 %no_underflow ret i1 %r } ; The comparison can be with any of the values being added. define i1 @t9(i8 %base, i8 %offset) { ; CHECK-LABEL: @t9( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %offset %r = and i1 %not_null, %no_underflow ret i1 %r } define i1 @t9_logical(i8 %base, i8 %offset) { ; CHECK-LABEL: @t9_logical( ; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[BASE:%.*]], 0 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) ; CHECK-NEXT: [[ADJUSTED:%.*]] = add i8 [[BASE]], [[OFFSET:%.*]] ; CHECK-NEXT: call void @use8(i8 [[ADJUSTED]]) ; CHECK-NEXT: [[TMP1:%.*]] = sub i8 0, [[BASE]] ; CHECK-NEXT: [[TMP2:%.*]] = icmp ult i8 [[TMP1]], [[OFFSET]] ; CHECK-NEXT: ret i1 [[TMP2]] ; %cmp = icmp slt i8 %base, 0 call void @llvm.assume(i1 %cmp) %adjusted = add i8 %base, %offset call void @use8(i8 %adjusted) %not_null = icmp ne i8 %adjusted, 0 %no_underflow = icmp ult i8 %adjusted, %offset %r = select i1 %not_null, i1 %no_underflow, i1 false ret i1 %r }