Skip to content

[InstCombine] Fold icmp spred (and X, highmask), C1 into icmp spred X, C2 #118197

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Dec 3, 2024
Merged

[InstCombine] Fold icmp spred (and X, highmask), C1 into icmp spred X, C2 #118197

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
aa94204
[InstCombine] Add pre-commit tests. NFC.
dtcxzyw Dec 1, 2024
41d53fd
Fold `icmp spred (and X, highmask), C1` into `icmp spred X, C2`
dtcxzyw Dec 1, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 11 additions & 0 deletions llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1760,6 +1760,17 @@ Instruction *InstCombinerImpl::foldICmpAndConstConst(ICmpInst &Cmp,
if (!match(And, m_And(m_Value(X), m_APInt(C2))))
return nullptr;

// (and X, highmask) s> [0, ~highmask] --> X s> ~highmask
if (Cmp.getPredicate() == ICmpInst::ICMP_SGT && C1.ule(~*C2) &&
C2->isNegatedPowerOf2())
return new ICmpInst(ICmpInst::ICMP_SGT, X,
ConstantInt::get(X->getType(), ~*C2));
// (and X, highmask) s< [1, -highmask] --> X s< -highmask
if (Cmp.getPredicate() == ICmpInst::ICMP_SLT && !C1.isSignMask() &&
(C1 - 1).ule(~*C2) && C2->isNegatedPowerOf2() && !C2->isSignMask())
return new ICmpInst(ICmpInst::ICMP_SLT, X,
ConstantInt::get(X->getType(), -*C2));

// Don't perform the following transforms if the AND has multiple uses
if (!And->hasOneUse())
return nullptr;
Expand Down
107 changes: 107 additions & 0 deletions llvm/test/Transforms/InstCombine/icmp-binop.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -252,3 +252,110 @@ false:
call void @use64(i64 %v)
ret i1 false
}

define i1 @test_icmp_sgt_and_negpow2_zero(i32 %add) {
; CHECK-LABEL: @test_icmp_sgt_and_negpow2_zero(
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[ADD:%.*]], 7
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -8
%cmp = icmp sgt i32 %and, 0
ret i1 %cmp
}

define i1 @test_icmp_slt_and_negpow2_one(i32 %add) {
; CHECK-LABEL: @test_icmp_slt_and_negpow2_one(
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[ADD:%.*]], 8
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -8
%cmp = icmp slt i32 %and, 1
ret i1 %cmp
}

define i1 @test_icmp_sgt_and_negpow2_nonzero(i32 %add) {
; CHECK-LABEL: @test_icmp_sgt_and_negpow2_nonzero(
; CHECK-NEXT: [[AND:%.*]] = and i32 [[ADD:%.*]], -8
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[AND]], -2
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -8
%cmp = icmp sgt i32 %and, -2
ret i1 %cmp
}

define i1 @test_icmp_sgt_and_nonnegpow2_zero(i32 %add) {
; CHECK-LABEL: @test_icmp_sgt_and_nonnegpow2_zero(
; CHECK-NEXT: [[AND:%.*]] = and i32 [[ADD:%.*]], 8
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[AND]], 0
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, 8
%cmp = icmp sgt i32 %and, 0
ret i1 %cmp
}

define i1 @test_icmp_ult_and_negpow2_one(i32 %add) {
; CHECK-LABEL: @test_icmp_ult_and_negpow2_one(
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[ADD:%.*]], 8
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -8
%cmp = icmp ult i32 %and, 1
ret i1 %cmp
}

define i1 @test_imply_dom_condition(i32 %add) {
; CHECK-LABEL: @test_imply_dom_condition(
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[ADD:%.*]], 7
; CHECK-NEXT: tail call void @llvm.assume(i1 [[CMP]])
; CHECK-NEXT: ret i1 false
;
%and = and i32 %add, -8
%cmp = icmp sgt i32 %and, 0
tail call void @llvm.assume(i1 %cmp)
%min.iters.check = icmp ult i32 %and, 8
ret i1 %min.iters.check
}

define i1 @test_icmp_slt_and_negpow2_c(i32 %add) {
; CHECK-LABEL: @test_icmp_slt_and_negpow2_c(
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[ADD:%.*]], 32
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -32
%cmp = icmp slt i32 %and, 16
ret i1 %cmp
}

define i1 @test_icmp_slt_and_negpow2_invalid_c(i32 %add) {
; CHECK-LABEL: @test_icmp_slt_and_negpow2_invalid_c(
; CHECK-NEXT: [[AND:%.*]] = and i32 [[ADD:%.*]], -32
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i32 [[AND]], 48
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -32
%cmp = icmp slt i32 %and, 48
ret i1 %cmp
}

define i1 @test_icmp_sgt_and_negpow2_c(i32 %add) {
; CHECK-LABEL: @test_icmp_sgt_and_negpow2_c(
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[ADD:%.*]], 31
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -32
%cmp = icmp sgt i32 %and, 16
ret i1 %cmp
}

define i1 @test_icmp_sgt_and_negpow2_invalid_c(i32 %add) {
; CHECK-LABEL: @test_icmp_sgt_and_negpow2_invalid_c(
; CHECK-NEXT: [[AND:%.*]] = and i32 [[ADD:%.*]], -32
; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[AND]], 48
; CHECK-NEXT: ret i1 [[CMP]]
;
%and = and i32 %add, -32
%cmp = icmp sgt i32 %and, 48
ret i1 %cmp
}
3 changes: 1 addition & 2 deletions llvm/test/Transforms/InstCombine/icmp.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2197,8 +2197,7 @@ define i1 @icmp_ashr_and_overshift(i8 %X) {

define i1 @icmp_and_ashr_neg_and_legal(i8 %x) {
; CHECK-LABEL: @icmp_and_ashr_neg_and_legal(
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[X:%.*]], -32
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[TMP1]], 16
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[X:%.*]], 32
; CHECK-NEXT: ret i1 [[CMP]]
;
%ashr = ashr i8 %x, 4
Expand Down
18 changes: 5 additions & 13 deletions llvm/test/Transforms/InstCombine/pr17827.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5,8 +5,7 @@
define i1 @test_shift_and_cmp_not_changed1(i8 %p) {
; CHECK-LABEL: @test_shift_and_cmp_not_changed1(
; CHECK-NEXT: [[SHLP:%.*]] = shl i8 [[P:%.*]], 5
; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[SHLP]], 64
; CHECK-NEXT: ret i1 [[CMP]]
;
%shlp = shl i8 %p, 5
Expand All @@ -18,10 +17,7 @@ define i1 @test_shift_and_cmp_not_changed1(i8 %p) {
; With arithmetic right shift, the comparison should not be modified.
define i1 @test_shift_and_cmp_not_changed2(i8 %p) {
; CHECK-LABEL: @test_shift_and_cmp_not_changed2(
; CHECK-NEXT: [[SHLP:%.*]] = ashr i8 [[P:%.*]], 5
; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32
; CHECK-NEXT: ret i1 [[CMP]]
; CHECK-NEXT: ret i1 true
;
%shlp = ashr i8 %p, 5
%andp = and i8 %shlp, -64
Expand All @@ -34,8 +30,7 @@ define i1 @test_shift_and_cmp_not_changed2(i8 %p) {
define i1 @test_shift_and_cmp_changed1(i8 %p, i8 %q) {
; CHECK-LABEL: @test_shift_and_cmp_changed1(
; CHECK-NEXT: [[ANDP:%.*]] = shl i8 [[P:%.*]], 5
; CHECK-NEXT: [[TMP1:%.*]] = and i8 [[ANDP]], -64
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[TMP1]], 32
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 33
; CHECK-NEXT: ret i1 [[CMP]]
;
%andp = and i8 %p, 6
Expand All @@ -50,8 +45,7 @@ define i1 @test_shift_and_cmp_changed1(i8 %p, i8 %q) {
define <2 x i1> @test_shift_and_cmp_changed1_vec(<2 x i8> %p, <2 x i8> %q) {
; CHECK-LABEL: @test_shift_and_cmp_changed1_vec(
; CHECK-NEXT: [[ANDP:%.*]] = shl <2 x i8> [[P:%.*]], splat (i8 5)
; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i8> [[ANDP]], splat (i8 -64)
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> [[TMP1]], splat (i8 32)
; CHECK-NEXT: [[CMP:%.*]] = icmp slt <2 x i8> [[ANDP]], splat (i8 33)
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%andp = and <2 x i8> %p, <i8 6, i8 6>
Expand Down Expand Up @@ -91,9 +85,7 @@ define <2 x i1> @test_shift_and_cmp_changed2_vec(<2 x i8> %p) {
; nsw on the shift should not affect the comparison.
define i1 @test_shift_and_cmp_changed3(i8 %p) {
; CHECK-LABEL: @test_shift_and_cmp_changed3(
; CHECK-NEXT: [[SHLP:%.*]] = shl nsw i8 [[P:%.*]], 5
; CHECK-NEXT: [[ANDP:%.*]] = and i8 [[SHLP]], -64
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[ANDP]], 32
; CHECK-NEXT: [[CMP:%.*]] = icmp slt i8 [[P:%.*]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
%shlp = shl nsw i8 %p, 5
Expand Down
Loading