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llvm-project/llvm/test/Transforms/InstCombine/result-of-add-of-negative-is-non-zero-and-no-underflow.ll
Nikita Popov a105877646
[InstCombine] Remove some of the complexity-based canonicalization (#91185) 
The idea behind this canonicalization is that it allows us to handle less
patterns, because we know that some will be canonicalized away. This is
indeed very useful to e.g. know that constants are always on the right.

However, this is only useful if the canonicalization is actually
reliable. This is the case for constants, but not for arguments: Moving
these to the right makes it look like the "more complex" expression is
guaranteed to be on the left, but this is not actually the case in
practice. It fails as soon as you replace the argument with another
instruction.

The end result is that it looks like things correctly work in tests,
while they actually don't. We use the "thwart complexity-based
canonicalization" trick to handle this in tests, but it's often a
challenge for new contributors to get this right, and based on the
regressions this PR originally exposed, we clearly don't get this right
in many cases.

For this reason, I think that it's better to remove this complexity
canonicalization. It will make it much easier to write tests for
commuted cases and make sure that they are handled.
2024-08-21 12:02:54 +02:00

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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[BASE]], [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%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: [[R:%.*]] = icmp ugt i8 [[BASE]], [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ule i8 [[OFFSET]], [[TMP1]]
; 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 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: [[R:%.*]] = icmp ule i8 [[OFFSET]], [[TMP1]]
; 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 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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%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: [[R:%.*]] = icmp ugt i8 [[OFFSET]], [[TMP1]]
; 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
%no_underflow = icmp ult i8 %adjusted, %offset
%r = select i1 %not_null, i1 %no_underflow, i1 false
ret i1 %r
}
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