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[InstCombine] Fold (x == y) ? 0 : (x > y ? 1 : -1) into `ucmp/scmp(…
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…x,y)` (llvm#107314)

This also handles commuted cases of the same fold, with either the
condition or the true/false values of the inner select being swapped.
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@Poseydon42
Poseydon42 authored Sep 23, 2024
1 parent 40d6497 commit d479849
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Showing 6 changed files with 191 additions and 61 deletions.
30 changes: 27 additions & 3 deletions llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3551,9 +3551,7 @@ Instruction *InstCombinerImpl::foldSelectToCmp(SelectInst &SI) {
Pred = ICmpInst::getSwappedPredicate(Pred);
std::swap(LHS, RHS);
}

Intrinsic::ID IID =
ICmpInst::isSigned(Pred) ? Intrinsic::scmp : Intrinsic::ucmp;
bool IsSigned = ICmpInst::isSigned(Pred);

bool Replace = false;
ICmpInst::Predicate ExtendedCmpPredicate;
Expand All @@ -3575,6 +3573,32 @@ Instruction *InstCombinerImpl::foldSelectToCmp(SelectInst &SI) {
ICmpInst::getSwappedPredicate(ExtendedCmpPredicate) == Pred))
Replace = true;

// (x == y) ? 0 : (x > y ? 1 : -1)
ICmpInst::Predicate FalseBranchSelectPredicate;
const APInt *InnerTV, *InnerFV;
if (Pred == ICmpInst::ICMP_EQ && match(TV, m_Zero()) &&
match(FV, m_Select(m_c_ICmp(FalseBranchSelectPredicate, m_Specific(LHS),
m_Specific(RHS)),
m_APInt(InnerTV), m_APInt(InnerFV)))) {
if (!ICmpInst::isGT(FalseBranchSelectPredicate)) {
FalseBranchSelectPredicate =
ICmpInst::getSwappedPredicate(FalseBranchSelectPredicate);
std::swap(LHS, RHS);
}

if (!InnerTV->isOne()) {
std::swap(InnerTV, InnerFV);
std::swap(LHS, RHS);
}

if (ICmpInst::isGT(FalseBranchSelectPredicate) && InnerTV->isOne() &&
InnerFV->isAllOnes()) {
IsSigned = ICmpInst::isSigned(FalseBranchSelectPredicate);
Replace = true;
}
}

Intrinsic::ID IID = IsSigned ? Intrinsic::scmp : Intrinsic::ucmp;
if (Replace)
return replaceInstUsesWith(
SI, Builder.CreateIntrinsic(SI.getType(), IID, {LHS, RHS}));
Expand Down
39 changes: 10 additions & 29 deletions llvm/test/Transforms/InstCombine/compare-3way.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -15,8 +15,7 @@ define void @test_low_sgt(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp ne i64 [[A]], [[B]]
; CHECK-NEXT: [[RESULT:%.*]] = zext i1 [[EQ]] to i32
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand Down Expand Up @@ -62,10 +61,7 @@ define void @test_low_sge(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i64 [[A]], [[B]]
; CHECK-NEXT: [[SLT:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[SLT]], i32 -1, i32 1
; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[EQ]], i32 0, i32 [[DOT]]
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand Down Expand Up @@ -114,8 +110,7 @@ define void @test_low_ne(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp ne i64 [[A]], [[B]]
; CHECK-NEXT: [[RESULT:%.*]] = zext i1 [[EQ]] to i32
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand Down Expand Up @@ -212,8 +207,7 @@ define void @test_mid_sge(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp ne i64 [[A]], [[B]]
; CHECK-NEXT: [[RESULT:%.*]] = zext i1 [[EQ]] to i32
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand All @@ -238,10 +232,7 @@ define void @test_mid_sle(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i64 [[A]], [[B]]
; CHECK-NEXT: [[SLT:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[SLT]], i32 -1, i32 1
; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[EQ]], i32 0, i32 [[DOT]]
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand All @@ -266,9 +257,8 @@ define void @test_mid_ne(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[SLT:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[SLT]], i32 -1, i32 1
; CHECK-NEXT: call void @use(i32 [[DOT]])
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
%eq = icmp eq i64 %a, %b
Expand Down Expand Up @@ -338,10 +328,7 @@ define void @test_high_slt(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i64 [[A]], [[B]]
; CHECK-NEXT: [[SLT:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[SLT]], i32 -1, i32 1
; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[EQ]], i32 0, i32 [[DOT]]
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand Down Expand Up @@ -389,10 +376,7 @@ define void @test_high_sle(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i64 [[A]], [[B]]
; CHECK-NEXT: [[SLT:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[SLT]], i32 -1, i32 1
; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[EQ]], i32 0, i32 [[DOT]]
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand All @@ -417,10 +401,7 @@ define void @test_high_ne(i64 %a, i64 %b) {
; CHECK: normal:
; CHECK-NEXT: ret void
; CHECK: unreached:
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i64 [[A]], [[B]]
; CHECK-NEXT: [[SLT:%.*]] = icmp slt i64 [[A]], [[B]]
; CHECK-NEXT: [[DOT:%.*]] = select i1 [[SLT]], i32 -1, i32 1
; CHECK-NEXT: [[RESULT:%.*]] = select i1 [[EQ]], i32 0, i32 [[DOT]]
; CHECK-NEXT: [[RESULT:%.*]] = call i32 @llvm.scmp.i32.i64(i64 [[A]], i64 [[B]])
; CHECK-NEXT: call void @use(i32 [[RESULT]])
; CHECK-NEXT: ret void
;
Expand Down
130 changes: 130 additions & 0 deletions llvm/test/Transforms/InstCombine/scmp.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -343,3 +343,133 @@ define i8 @scmp_from_select_gt_and_lt(i32 %x, i32 %y) {
%r = select i1 %gt, i8 1, i8 %lt
ret i8 %r
}

; (x == y) ? 0 : (x s> y ? 1 : -1) into scmp(x, y)
define i8 @scmp_from_select_eq_and_gt(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[X]], i32 [[Y]])
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp sgt i32 %x, %y
%sel1 = select i1 %gt, i8 1, i8 -1
%r = select i1 %eq, i8 0, i8 %sel1
ret i8 %r
}

define i8 @scmp_from_select_eq_and_gt_inverse(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_inverse(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[X]], i32 [[Y]])
; CHECK-NEXT: ret i8 [[R]]
;
%ne = icmp ne i32 %x, %y
%gt = icmp sgt i32 %x, %y
%sel1 = select i1 %gt, i8 1, i8 -1
%r = select i1 %ne, i8 %sel1, i8 0
ret i8 %r
}

define <4 x i8> @scmp_from_select_eq_and_gt_vec(<4 x i32> %x, <4 x i32> %y) {
; CHECK-LABEL: define <4 x i8> @scmp_from_select_eq_and_gt_vec(
; CHECK-SAME: <4 x i32> [[X:%.*]], <4 x i32> [[Y:%.*]]) {
; CHECK-NEXT: [[R:%.*]] = call <4 x i8> @llvm.scmp.v4i8.v4i32(<4 x i32> [[X]], <4 x i32> [[Y]])
; CHECK-NEXT: ret <4 x i8> [[R]]
;
%eq = icmp eq <4 x i32> %x, %y
%gt = icmp sgt <4 x i32> %x, %y
%sel1 = select <4 x i1> %gt, <4 x i8> splat(i8 1), <4 x i8> splat(i8 -1)
%r = select <4 x i1> %eq, <4 x i8> splat(i8 0), <4 x i8> %sel1
ret <4 x i8> %r
}

define i8 @scmp_from_select_eq_and_gt_commuted1(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_commuted1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[Y]], i32 [[X]])
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp slt i32 %x, %y
%sel1 = select i1 %gt, i8 1, i8 -1
%r = select i1 %eq, i8 0, i8 %sel1
ret i8 %r
}

define i8 @scmp_from_select_eq_and_gt_commuted2(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_commuted2(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[Y]], i32 [[X]])
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp sgt i32 %x, %y
%sel1 = select i1 %gt, i8 -1, i8 1
%r = select i1 %eq, i8 0, i8 %sel1
ret i8 %r
}

define i8 @scmp_from_select_eq_and_gt_commuted3(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_commuted3(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[R:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[X]], i32 [[Y]])
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp slt i32 %x, %y
%sel1 = select i1 %gt, i8 -1, i8 1
%r = select i1 %eq, i8 0, i8 %sel1
ret i8 %r
}

; Negative test: true value of outer select is not zero
define i8 @scmp_from_select_eq_and_gt_neg1(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_neg1(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: [[GT:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: [[SEL1:%.*]] = select i1 [[GT]], i8 1, i8 -1
; CHECK-NEXT: [[R:%.*]] = select i1 [[EQ]], i8 5, i8 [[SEL1]]
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp sgt i32 %x, %y
%sel1 = select i1 %gt, i8 1, i8 -1
%r = select i1 %eq, i8 5, i8 %sel1
ret i8 %r
}

; Negative test: true value of inner select is not 1 or -1
define i8 @scmp_from_select_eq_and_gt_neg2(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_neg2(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: [[GT:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: [[SEL1:%.*]] = select i1 [[GT]], i8 2, i8 -1
; CHECK-NEXT: [[R:%.*]] = select i1 [[EQ]], i8 0, i8 [[SEL1]]
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp sgt i32 %x, %y
%sel1 = select i1 %gt, i8 2, i8 -1
%r = select i1 %eq, i8 0, i8 %sel1
ret i8 %r
}

; Negative test: false value of inner select is not 1 or -1
define i8 @scmp_from_select_eq_and_gt_neg3(i32 %x, i32 %y) {
; CHECK-LABEL: define i8 @scmp_from_select_eq_and_gt_neg3(
; CHECK-SAME: i32 [[X:%.*]], i32 [[Y:%.*]]) {
; CHECK-NEXT: [[EQ:%.*]] = icmp eq i32 [[X]], [[Y]]
; CHECK-NEXT: [[GT:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: [[SEL1:%.*]] = select i1 [[GT]], i8 1, i8 22
; CHECK-NEXT: [[R:%.*]] = select i1 [[EQ]], i8 0, i8 [[SEL1]]
; CHECK-NEXT: ret i8 [[R]]
;
%eq = icmp eq i32 %x, %y
%gt = icmp sgt i32 %x, %y
%sel1 = select i1 %gt, i8 1, i8 22
%r = select i1 %eq, i8 0, i8 %sel1
ret i8 %r
}
30 changes: 7 additions & 23 deletions llvm/test/Transforms/InstCombine/select-select.ll
View file
Original file line number Diff line number Diff line change
Expand Up @@ -177,10 +177,7 @@ define <2 x i8> @sel_shuf_narrowing_commute2(<4 x i8> %x, <4 x i8> %y, <2 x i8>

define i8 @strong_order_cmp_slt_eq(i32 %a, i32 %b) {
; CHECK-LABEL: @strong_order_cmp_slt_eq(
; CHECK-NEXT: [[CMP_LT:%.*]] = icmp slt i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[SEL_LT:%.*]] = select i1 [[CMP_LT]], i8 -1, i8 1
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A]], [[B]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = select i1 [[CMP_EQ]], i8 0, i8 [[SEL_LT]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[A:%.*]], i32 [[B:%.*]])
; CHECK-NEXT: ret i8 [[SEL_EQ]]
;
%cmp.lt = icmp slt i32 %a, %b
Expand All @@ -192,10 +189,7 @@ define i8 @strong_order_cmp_slt_eq(i32 %a, i32 %b) {

define i8 @strong_order_cmp_ult_eq(i32 %a, i32 %b) {
; CHECK-LABEL: @strong_order_cmp_ult_eq(
; CHECK-NEXT: [[CMP_LT:%.*]] = icmp ult i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[SEL_LT:%.*]] = select i1 [[CMP_LT]], i8 -1, i8 1
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A]], [[B]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = select i1 [[CMP_EQ]], i8 0, i8 [[SEL_LT]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = call i8 @llvm.ucmp.i8.i32(i32 [[A:%.*]], i32 [[B:%.*]])
; CHECK-NEXT: ret i8 [[SEL_EQ]]
;
%cmp.lt = icmp ult i32 %a, %b
Expand Down Expand Up @@ -252,10 +246,7 @@ define i8 @strong_order_cmp_slt_ult_wrong_pred(i32 %a, i32 %b) {

define i8 @strong_order_cmp_sgt_eq(i32 %a, i32 %b) {
; CHECK-LABEL: @strong_order_cmp_sgt_eq(
; CHECK-NEXT: [[CMP_GT:%.*]] = icmp sgt i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[SEL_GT:%.*]] = select i1 [[CMP_GT]], i8 1, i8 -1
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A]], [[B]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = select i1 [[CMP_EQ]], i8 0, i8 [[SEL_GT]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[A:%.*]], i32 [[B:%.*]])
; CHECK-NEXT: ret i8 [[SEL_EQ]]
;
%cmp.gt = icmp sgt i32 %a, %b
Expand All @@ -267,10 +258,7 @@ define i8 @strong_order_cmp_sgt_eq(i32 %a, i32 %b) {

define i8 @strong_order_cmp_ugt_eq(i32 %a, i32 %b) {
; CHECK-LABEL: @strong_order_cmp_ugt_eq(
; CHECK-NEXT: [[CMP_GT:%.*]] = icmp ugt i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[SEL_GT:%.*]] = select i1 [[CMP_GT]], i8 1, i8 -1
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A]], [[B]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = select i1 [[CMP_EQ]], i8 0, i8 [[SEL_GT]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = call i8 @llvm.ucmp.i8.i32(i32 [[A:%.*]], i32 [[B:%.*]])
; CHECK-NEXT: ret i8 [[SEL_EQ]]
;
%cmp.gt = icmp ugt i32 %a, %b
Expand Down Expand Up @@ -395,9 +383,7 @@ define i8 @strong_order_cmp_slt_eq_slt_not_oneuse(i32 %a, i32 %b) {
; CHECK-LABEL: @strong_order_cmp_slt_eq_slt_not_oneuse(
; CHECK-NEXT: [[CMP_LT:%.*]] = icmp slt i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: call void @use1(i1 [[CMP_LT]])
; CHECK-NEXT: [[SEL_LT:%.*]] = select i1 [[CMP_LT]], i8 -1, i8 1
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A]], [[B]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = select i1 [[CMP_EQ]], i8 0, i8 [[SEL_LT]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[A]], i32 [[B]])
; CHECK-NEXT: ret i8 [[SEL_EQ]]
;
%cmp.lt = icmp slt i32 %a, %b
Expand All @@ -410,11 +396,9 @@ define i8 @strong_order_cmp_slt_eq_slt_not_oneuse(i32 %a, i32 %b) {

define i8 @strong_order_cmp_sgt_eq_eq_not_oneuse(i32 %a, i32 %b) {
; CHECK-LABEL: @strong_order_cmp_sgt_eq_eq_not_oneuse(
; CHECK-NEXT: [[CMP_GT:%.*]] = icmp sgt i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[SEL_GT:%.*]] = select i1 [[CMP_GT]], i8 1, i8 -1
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A]], [[B]]
; CHECK-NEXT: [[CMP_EQ:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: call void @use1(i1 [[CMP_EQ]])
; CHECK-NEXT: [[SEL_EQ:%.*]] = select i1 [[CMP_EQ]], i8 0, i8 [[SEL_GT]]
; CHECK-NEXT: [[SEL_EQ:%.*]] = call i8 @llvm.scmp.i8.i32(i32 [[A]], i32 [[B]])
; CHECK-NEXT: ret i8 [[SEL_EQ]]
;
%cmp.gt = icmp sgt i32 %a, %b
Expand Down
9 changes: 3 additions & 6 deletions llvm/test/Transforms/InstCombine/sink_to_unreachable.ll
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,8 +10,7 @@ define void @test_01(i32 %x, i32 %y) {
; CHECK-NEXT: [[C2:%.*]] = icmp slt i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: br i1 [[C2]], label [[EXIT:%.*]], label [[UNREACHED:%.*]]
; CHECK: unreached:
; CHECK-NEXT: [[C1:%.*]] = icmp ne i32 [[X]], [[Y]]
; CHECK-NEXT: [[COMPARATOR:%.*]] = zext i1 [[C1]] to i32
; CHECK-NEXT: [[COMPARATOR:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[X]], i32 [[Y]])
; CHECK-NEXT: call void @use(i32 [[COMPARATOR]])
; CHECK-NEXT: unreachable
; CHECK: exit:
Expand Down Expand Up @@ -42,8 +41,7 @@ define void @test_02(i32 %x, i32 %y) {
; CHECK-NEXT: [[C3:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: br i1 [[C3]], label [[EXIT]], label [[UNREACHED:%.*]]
; CHECK: unreached:
; CHECK-NEXT: [[C1:%.*]] = icmp ne i32 [[X]], [[Y]]
; CHECK-NEXT: [[COMPARATOR:%.*]] = zext i1 [[C1]] to i32
; CHECK-NEXT: [[COMPARATOR:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[X]], i32 [[Y]])
; CHECK-NEXT: call void @use(i32 [[COMPARATOR]])
; CHECK-NEXT: unreachable
; CHECK: exit:
Expand Down Expand Up @@ -77,8 +75,7 @@ define i32 @test_03(i32 %x, i32 %y) {
; CHECK-NEXT: [[C3:%.*]] = icmp sgt i32 [[X]], [[Y]]
; CHECK-NEXT: br i1 [[C3]], label [[EXIT]], label [[UNREACHED:%.*]]
; CHECK: unreached:
; CHECK-NEXT: [[C1:%.*]] = icmp ne i32 [[X]], [[Y]]
; CHECK-NEXT: [[COMPARATOR:%.*]] = zext i1 [[C1]] to i32
; CHECK-NEXT: [[COMPARATOR:%.*]] = call i32 @llvm.scmp.i32.i32(i32 [[X]], i32 [[Y]])
; CHECK-NEXT: ret i32 [[COMPARATOR]]
; CHECK: exit:
; CHECK-NEXT: ret i32 0
Expand Down
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