shylie/llvm-project
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
llvm-project/llvm/test/Transforms/InstCombine/implies.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

425 lines
12 KiB
LLVM
Raw Permalink Blame History

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
define i1 @or_implies_sle(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @or_implies_sle(
; CHECK-NEXT: [[OR:%.*]] = or i8 [[X:%.*]], 23
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[OR]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%or = or i8 %x, 23
%cond = icmp sle i8 %or, %y
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @or_implies_sle_fail(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @or_implies_sle_fail(
; CHECK-NEXT: [[OR:%.*]] = or i8 [[X:%.*]], -34
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[OR]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: [[R:%.*]] = icmp sle i8 [[X]], [[Y]]
; CHECK-NEXT: ret i1 [[R]]
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%or = or i8 %x, -34
%cond = icmp sle i8 %or, %y
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @or_distjoint_implies_ule(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @or_distjoint_implies_ule(
; CHECK-NEXT: [[X2:%.*]] = or disjoint i8 [[X:%.*]], 24
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[X2]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x1 = or disjoint i8 %x, 23
%x2 = or disjoint i8 %x, 24
%cond = icmp ule i8 %x2, %y
br i1 %cond, label %T, label %F
T:
%r = icmp ule i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @or_distjoint_implies_ule_fail(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @or_distjoint_implies_ule_fail(
; CHECK-NEXT: [[X2:%.*]] = or disjoint i8 [[X:%.*]], 24
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[X2]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: [[X1:%.*]] = or disjoint i8 [[X]], 28
; CHECK-NEXT: [[R:%.*]] = icmp ule i8 [[X1]], [[Y]]
; CHECK-NEXT: ret i1 [[R]]
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x1 = or disjoint i8 %x, 28
%x2 = or disjoint i8 %x, 24
%cond = icmp ule i8 %x2, %y
br i1 %cond, label %T, label %F
T:
%r = icmp ule i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @or_prove_distjoin_implies_ule(i8 %xx, i8 %y, i1 %other) {
; CHECK-LABEL: @or_prove_distjoin_implies_ule(
; CHECK-NEXT: [[X:%.*]] = and i8 [[XX:%.*]], -16
; CHECK-NEXT: [[X2:%.*]] = or disjoint i8 [[X]], 10
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[X2]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x = and i8 %xx, -16
%x1 = or i8 %x, 7
%x2 = or i8 %x, 10
%cond = icmp ule i8 %x2, %y
br i1 %cond, label %T, label %F
T:
%r = icmp ule i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @src_or_distjoint_implies_sle(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @src_or_distjoint_implies_sle(
; CHECK-NEXT: [[X2:%.*]] = or disjoint i8 [[X:%.*]], 24
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[X2]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x1 = or disjoint i8 %x, 23
%x2 = or disjoint i8 %x, 24
%cond = icmp sle i8 %x2, %y
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @src_or_distjoint_implies_sle_fail(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @src_or_distjoint_implies_sle_fail(
; CHECK-NEXT: [[X2:%.*]] = or disjoint i8 [[X:%.*]], 24
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[Y:%.*]], [[X2]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: [[X1:%.*]] = or disjoint i8 [[X]], 23
; CHECK-NEXT: [[R:%.*]] = icmp sle i8 [[X1]], [[Y]]
; CHECK-NEXT: ret i1 [[R]]
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x1 = or disjoint i8 %x, 23
%x2 = or disjoint i8 %x, 24
%cond = icmp sle i8 %y, %x2
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @src_addnsw_implies_sle(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @src_addnsw_implies_sle(
; CHECK-NEXT: [[X2:%.*]] = add nsw i8 [[X:%.*]], 24
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[X2]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x1 = add nsw i8 %x, 23
%x2 = add nsw i8 %x, 24
%cond = icmp sle i8 %x2, %y
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @src_addnsw_implies_sle_fail(i8 %x, i8 %y, i1 %other) {
; CHECK-LABEL: @src_addnsw_implies_sle_fail(
; CHECK-NEXT: [[X2:%.*]] = add nsw i8 [[X:%.*]], 23
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[X2]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: [[X1:%.*]] = add nsw i8 [[X]], 24
; CHECK-NEXT: [[R:%.*]] = icmp sle i8 [[X1]], [[Y]]
; CHECK-NEXT: ret i1 [[R]]
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%x1 = add nsw i8 %x, 24
%x2 = add nsw i8 %x, 23
%cond = icmp sle i8 %x2, %y
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x1, %y
ret i1 %r
F:
ret i1 %other
}
define i1 @src_and_implies_ult(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_and_implies_ult(
; CHECK-NEXT: [[COND:%.*]] = icmp ult i8 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND]], label [[T:%.*]], label [[F:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%cond = icmp ult i8 %x, %z
br i1 %cond, label %T, label %F
T:
%and = and i8 %z, %x
%r = icmp ult i8 %and, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_and_implies_ult_fail(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_and_implies_ult_fail(
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[Z]]
; CHECK-NEXT: [[R:%.*]] = icmp ne i8 [[AND]], [[Z]]
; CHECK-NEXT: ret i1 [[R]]
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%cond = icmp ule i8 %x, %z
br i1 %cond, label %T, label %F
T:
%and = and i8 %x, %z
%r = icmp ult i8 %and, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_and_implies_slt_fail(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_and_implies_slt_fail(
; CHECK-NEXT: [[COND:%.*]] = icmp slt i8 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND]], label [[T:%.*]], label [[F:%.*]]
; CHECK: T:
; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = icmp slt i8 [[AND]], [[Z]]
; CHECK-NEXT: ret i1 [[R]]
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%cond = icmp slt i8 %x, %z
br i1 %cond, label %T, label %F
T:
%and = and i8 %x, %y
%r = icmp slt i8 %and, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_or_implies_ule(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_or_implies_ule(
; CHECK-NEXT: [[OR:%.*]] = or i8 [[Y:%.*]], [[X:%.*]]
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ult i8 [[Z:%.*]], [[OR]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%or = or i8 %y, %x
%cond = icmp uge i8 %z, %or
br i1 %cond, label %T, label %F
T:
%r = icmp ule i8 %x, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_or_implies_false_ugt_todo(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_or_implies_false_ugt_todo(
; CHECK-NEXT: [[OR:%.*]] = or i8 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[COND:%.*]] = icmp ugt i8 [[OR]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND]], label [[T:%.*]], label [[F:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
; CHECK: F:
; CHECK-NEXT: [[R:%.*]] = icmp ugt i8 [[X]], [[Z]]
; CHECK-NEXT: ret i1 [[R]]
;
%or = or i8 %x, %y
%cond = icmp ugt i8 %or, %z
br i1 %cond, label %T, label %F
T:
ret i1 %other
F:
%r = icmp ugt i8 %x, %z
ret i1 %r
}
define i1 @src_udiv_implies_ult(i8 %x, i8 %z, i1 %other) {
; CHECK-LABEL: @src_udiv_implies_ult(
; CHECK-NEXT: [[COND:%.*]] = icmp ugt i8 [[Z:%.*]], [[X:%.*]]
; CHECK-NEXT: br i1 [[COND]], label [[T:%.*]], label [[F:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%cond = icmp ugt i8 %z, %x
br i1 %cond, label %T, label %F
T:
%and = udiv i8 %x, 3
%r = icmp ult i8 %and, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_udiv_implies_ult2(i8 %x, i8 %z, i1 %other) {
; CHECK-LABEL: @src_udiv_implies_ult2(
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[Z:%.*]], [[X:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
; CHECK: F:
; CHECK-NEXT: ret i1 true
;
%cond = icmp ule i8 %z, %x
br i1 %cond, label %T, label %F
T:
ret i1 %other
F:
%and = udiv i8 %x, 3
%r = icmp ult i8 %and, %z
ret i1 %r
}
define i1 @src_smin_implies_sle(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_smin_implies_sle(
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%cond = icmp sle i8 %x, %z
br i1 %cond, label %T, label %F
T:
%um = call i8 @llvm.smin.i8(i8 %x, i8 %y)
%r = icmp sle i8 %um, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_umin_implies_ule(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_umin_implies_ule(
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%cond = icmp ule i8 %x, %z
br i1 %cond, label %T, label %F
T:
%um = call i8 @llvm.umin.i8(i8 %x, i8 %y)
%r = icmp ule i8 %um, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_umax_implies_ule(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_umax_implies_ule(
; CHECK-NEXT: [[UM:%.*]] = call i8 @llvm.umax.i8(i8 [[X:%.*]], i8 [[Y:%.*]])
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp ugt i8 [[UM]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%um = call i8 @llvm.umax.i8(i8 %x, i8 %y)
%cond = icmp ule i8 %um, %z
br i1 %cond, label %T, label %F
T:
%r = icmp ule i8 %x, %z
ret i1 %r
F:
ret i1 %other
}
define i1 @src_smax_implies_sle(i8 %x, i8 %y, i8 %z, i1 %other) {
; CHECK-LABEL: @src_smax_implies_sle(
; CHECK-NEXT: [[UM:%.*]] = call i8 @llvm.smax.i8(i8 [[X:%.*]], i8 [[Y:%.*]])
; CHECK-NEXT: [[COND_NOT:%.*]] = icmp sgt i8 [[UM]], [[Z:%.*]]
; CHECK-NEXT: br i1 [[COND_NOT]], label [[F:%.*]], label [[T:%.*]]
; CHECK: T:
; CHECK-NEXT: ret i1 true
; CHECK: F:
; CHECK-NEXT: ret i1 [[OTHER:%.*]]
;
%um = call i8 @llvm.smax.i8(i8 %x, i8 %y)
%cond = icmp sle i8 %um, %z
br i1 %cond, label %T, label %F
T:
%r = icmp sle i8 %x, %z
ret i1 %r
F:
ret i1 %other
}
Reference in New Issue View Git Blame Copy Permalink