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[InstCombine] Fold umax(smax)/smin(umin) with non-negative constants #82929

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Feb 25, 2024
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[InstCombine] Fold umax(smax)/smin(umin) with non-negative constants #82929

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5909cff
[InstCombine] Add pre-commit tests. NFC.
dtcxzyw Feb 25, 2024
485cea4
[InstCombine] Fold umax(smax)/smin(umin) with non-negative constants
dtcxzyw Feb 25, 2024
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23 changes: 17 additions & 6 deletions llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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Expand Up @@ -1220,22 +1220,33 @@ static Instruction *foldClampRangeOfTwo(IntrinsicInst *II,
/// If this min/max has a constant operand and an operand that is a matching
/// min/max with a constant operand, constant-fold the 2 constant operands.
static Value *reassociateMinMaxWithConstants(IntrinsicInst *II,
IRBuilderBase &Builder) {
IRBuilderBase &Builder,
const SimplifyQuery &SQ) {
Intrinsic::ID MinMaxID = II->getIntrinsicID();
auto *LHS = dyn_cast<IntrinsicInst>(II->getArgOperand(0));
if (!LHS || LHS->getIntrinsicID() != MinMaxID)
auto *LHS = dyn_cast<MinMaxIntrinsic>(II->getArgOperand(0));
if (!LHS)
return nullptr;

Constant *C0, *C1;
if (!match(LHS->getArgOperand(1), m_ImmConstant(C0)) ||
!match(II->getArgOperand(1), m_ImmConstant(C1)))
return nullptr;

// max (max X, C0), C1 --> max X, (max C0, C1) --> max X, NewC
// max (max X, C0), C1 --> max X, (max C0, C1)
// min (min X, C0), C1 --> min X, (min C0, C1)
// umax (smax X, nneg C0), nneg C1 --> smax X, (umax C0, C1)
// smin (umin X, nneg C0), nneg C1 --> umin X, (smin C0, C1)
Intrinsic::ID InnerMinMaxID = LHS->getIntrinsicID();
if (InnerMinMaxID != MinMaxID &&
!(((MinMaxID == Intrinsic::umax && InnerMinMaxID == Intrinsic::smax) ||
(MinMaxID == Intrinsic::smin && InnerMinMaxID == Intrinsic::umin)) &&
isKnownNonNegative(C0, SQ) && isKnownNonNegative(C1, SQ)))
return nullptr;

ICmpInst::Predicate Pred = MinMaxIntrinsic::getPredicate(MinMaxID);
Value *CondC = Builder.CreateICmp(Pred, C0, C1);
Value *NewC = Builder.CreateSelect(CondC, C0, C1);
return Builder.CreateIntrinsic(MinMaxID, II->getType(),
return Builder.CreateIntrinsic(InnerMinMaxID, II->getType(),
{LHS->getArgOperand(0), NewC});
}

Expand Down Expand Up @@ -1786,7 +1797,7 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
if (Instruction *SAdd = matchSAddSubSat(*II))
return SAdd;

if (Value *NewMinMax = reassociateMinMaxWithConstants(II, Builder))
if (Value *NewMinMax = reassociateMinMaxWithConstants(II, Builder, SQ))
return replaceInstUsesWith(*II, NewMinMax);

if (Instruction *R = reassociateMinMaxWithConstantInOperand(II, Builder))
Expand Down
127 changes: 125 additions & 2 deletions llvm/test/Transforms/InstCombine/minmax-fold.ll
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Expand Up @@ -316,8 +316,7 @@ define i32 @test73(i32 %x) {
; SMAX(SMAX(X, 36), 75) -> SMAX(X, 75)
define i32 @test74(i32 %x) {
; CHECK-LABEL: @test74(
; CHECK-NEXT: [[COND:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 36)
; CHECK-NEXT: [[RETVAL:%.*]] = call i32 @llvm.umax.i32(i32 [[COND]], i32 75)
; CHECK-NEXT: [[RETVAL:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 75)
; CHECK-NEXT: ret i32 [[RETVAL]]
;
%cmp = icmp slt i32 %x, 36
Expand Down Expand Up @@ -1419,3 +1418,127 @@ entry:
%r = select i1 %cmp2, i32 %s1, i32 %k1
ret i32 %r
}

define i32 @test_umax_smax1(i32 %x) {
; CHECK-LABEL: @test_umax_smax1(
; CHECK-NEXT: [[UMAX:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 1)
; CHECK-NEXT: ret i32 [[UMAX]]
;
%smax = call i32 @llvm.smax.i32(i32 %x, i32 0)
%umax = call i32 @llvm.umax.i32(i32 %smax, i32 1)
ret i32 %umax
}

define i32 @test_umax_smax2(i32 %x) {
; CHECK-LABEL: @test_umax_smax2(
; CHECK-NEXT: [[SMAX:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 20)
; CHECK-NEXT: ret i32 [[SMAX]]
;
%smax = call i32 @llvm.smax.i32(i32 %x, i32 20)
%umax = call i32 @llvm.umax.i32(i32 %smax, i32 10)
ret i32 %umax
}

define <2 x i32> @test_umax_smax_vec(<2 x i32> %x) {
; CHECK-LABEL: @test_umax_smax_vec(
; CHECK-NEXT: [[UMAX:%.*]] = call <2 x i32> @llvm.smax.v2i32(<2 x i32> [[X:%.*]], <2 x i32> <i32 1, i32 20>)
; CHECK-NEXT: ret <2 x i32> [[UMAX]]
;
%smax = call <2 x i32> @llvm.smax.v2i32(<2 x i32> %x, <2 x i32> <i32 0, i32 20>)
%umax = call <2 x i32> @llvm.umax.v2i32(<2 x i32> %smax, <2 x i32> <i32 1, i32 10>)
ret <2 x i32> %umax
}

define i32 @test_smin_umin1(i32 %x) {
; CHECK-LABEL: @test_smin_umin1(
; CHECK-NEXT: [[SMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[X:%.*]], i32 10)
; CHECK-NEXT: ret i32 [[SMIN]]
;
%smin = call i32 @llvm.umin.i32(i32 %x, i32 10)
%umin = call i32 @llvm.smin.i32(i32 %smin, i32 20)
ret i32 %umin
}

define i32 @test_smin_umin2(i32 %x) {
; CHECK-LABEL: @test_smin_umin2(
; CHECK-NEXT: [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[X:%.*]], i32 10)
; CHECK-NEXT: ret i32 [[UMIN]]
;
%smin = call i32 @llvm.umin.i32(i32 %x, i32 20)
%umin = call i32 @llvm.smin.i32(i32 %smin, i32 10)
ret i32 %umin
}

define <2 x i32> @test_smin_umin_vec(<2 x i32> %x) {
; CHECK-LABEL: @test_smin_umin_vec(
; CHECK-NEXT: [[UMIN:%.*]] = call <2 x i32> @llvm.umin.v2i32(<2 x i32> [[X:%.*]], <2 x i32> <i32 10, i32 10>)
; CHECK-NEXT: ret <2 x i32> [[UMIN]]
;
%smin = call <2 x i32> @llvm.umin.v2i32(<2 x i32> %x, <2 x i32> <i32 10, i32 20>)
%umin = call <2 x i32> @llvm.smin.v2i32(<2 x i32> %smin, <2 x i32> <i32 20, i32 10>)
ret <2 x i32> %umin
}

; Negative tests

define i32 @test_umax_smax3(i32 %x) {
; CHECK-LABEL: @test_umax_smax3(
; CHECK-NEXT: ret i32 -1
;
%smax = call i32 @llvm.smax.i32(i32 %x, i32 0)
%umax = call i32 @llvm.umax.i32(i32 %smax, i32 -1)
ret i32 %umax
}

define i32 @test_umax_smax4(i32 %x) {
; CHECK-LABEL: @test_umax_smax4(
; CHECK-NEXT: [[SMAX:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 -20)
; CHECK-NEXT: [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[SMAX]], i32 10)
; CHECK-NEXT: ret i32 [[UMAX]]
;
%smax = call i32 @llvm.smax.i32(i32 %x, i32 -20)
%umax = call i32 @llvm.umax.i32(i32 %smax, i32 10)
ret i32 %umax
}

define i32 @test_smin_umin3(i32 %x) {
; CHECK-LABEL: @test_smin_umin3(
; CHECK-NEXT: ret i32 -20
;
%smin = call i32 @llvm.umin.i32(i32 %x, i32 10)
%umin = call i32 @llvm.smin.i32(i32 %smin, i32 -20)
ret i32 %umin
}

define i32 @test_smin_umin4(i32 %x) {
; CHECK-LABEL: @test_smin_umin4(
; CHECK-NEXT: [[SMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[X:%.*]], i32 -20)
; CHECK-NEXT: [[UMIN:%.*]] = call i32 @llvm.smin.i32(i32 [[SMIN]], i32 10)
; CHECK-NEXT: ret i32 [[UMIN]]
;
%smin = call i32 @llvm.umin.i32(i32 %x, i32 -20)
%umin = call i32 @llvm.smin.i32(i32 %smin, i32 10)
ret i32 %umin
}

define i32 @test_umax_nonminmax(i32 %x) {
; CHECK-LABEL: @test_umax_nonminmax(
; CHECK-NEXT: [[Y:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range [[RNG0:![0-9]+]]
; CHECK-NEXT: [[UMAX:%.*]] = call i32 @llvm.umax.i32(i32 [[Y]], i32 1)
; CHECK-NEXT: ret i32 [[UMAX]]
;
%y = call i32 @llvm.ctpop.i32(i32 %x)
%umax = call i32 @llvm.umax.i32(i32 %y, i32 1)
ret i32 %umax
}

define <2 x i32> @test_umax_smax_vec_neg(<2 x i32> %x) {
; CHECK-LABEL: @test_umax_smax_vec_neg(
; CHECK-NEXT: [[SMAX:%.*]] = call <2 x i32> @llvm.smax.v2i32(<2 x i32> [[X:%.*]], <2 x i32> <i32 0, i32 -20>)
; CHECK-NEXT: [[UMAX:%.*]] = call <2 x i32> @llvm.umax.v2i32(<2 x i32> [[SMAX]], <2 x i32> <i32 1, i32 10>)
; CHECK-NEXT: ret <2 x i32> [[UMAX]]
;
%smax = call <2 x i32> @llvm.smax.v2i32(<2 x i32> %x, <2 x i32> <i32 0, i32 -20>)
%umax = call <2 x i32> @llvm.umax.v2i32(<2 x i32> %smax, <2 x i32> <i32 1, i32 10>)
ret <2 x i32> %umax
}
17 changes: 8 additions & 9 deletions llvm/test/Transforms/InstCombine/select_meta.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -171,8 +171,7 @@ define i32 @test72(i32 %x) {
; SMAX(SMAX(X, 36), 75) -> SMAX(X, 75)
define i32 @test74(i32 %x) {
; CHECK-LABEL: @test74(
; CHECK-NEXT: [[COND:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 36)
; CHECK-NEXT: [[RETVAL:%.*]] = call i32 @llvm.umax.i32(i32 [[COND]], i32 75)
; CHECK-NEXT: [[RETVAL:%.*]] = call i32 @llvm.smax.i32(i32 [[X:%.*]], i32 75)
; CHECK-NEXT: ret i32 [[RETVAL]]
;
%cmp = icmp slt i32 %x, 36
Expand Down Expand Up @@ -317,7 +316,7 @@ define <2 x i32> @not_cond_vec_undef(<2 x i1> %c, <2 x i32> %tv, <2 x i32> %fv)

define i64 @select_add(i1 %cond, i64 %x, i64 %y) {
; CHECK-LABEL: @select_add(
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], i64 [[Y:%.*]], i64 0, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], i64 [[Y:%.*]], i64 0, !prof [[PROF0]], !unpredictable [[META2:![0-9]+]]
; CHECK-NEXT: [[RET:%.*]] = add i64 [[OP]], [[X:%.*]]
; CHECK-NEXT: ret i64 [[RET]]
;
Expand All @@ -328,7 +327,7 @@ define i64 @select_add(i1 %cond, i64 %x, i64 %y) {

define <2 x i32> @select_or(<2 x i1> %cond, <2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @select_or(
; CHECK-NEXT: [[OP:%.*]] = select <2 x i1> [[COND:%.*]], <2 x i32> [[Y:%.*]], <2 x i32> zeroinitializer, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: [[OP:%.*]] = select <2 x i1> [[COND:%.*]], <2 x i32> [[Y:%.*]], <2 x i32> zeroinitializer, !prof [[PROF0]], !unpredictable [[META2]]
; CHECK-NEXT: [[RET:%.*]] = or <2 x i32> [[OP]], [[X:%.*]]
; CHECK-NEXT: ret <2 x i32> [[RET]]
;
Expand All @@ -339,7 +338,7 @@ define <2 x i32> @select_or(<2 x i1> %cond, <2 x i32> %x, <2 x i32> %y) {

define i17 @select_sub(i1 %cond, i17 %x, i17 %y) {
; CHECK-LABEL: @select_sub(
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], i17 [[Y:%.*]], i17 0, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], i17 [[Y:%.*]], i17 0, !prof [[PROF0]], !unpredictable [[META2]]
; CHECK-NEXT: [[RET:%.*]] = sub i17 [[X:%.*]], [[OP]]
; CHECK-NEXT: ret i17 [[RET]]
;
Expand All @@ -350,7 +349,7 @@ define i17 @select_sub(i1 %cond, i17 %x, i17 %y) {

define i128 @select_ashr(i1 %cond, i128 %x, i128 %y) {
; CHECK-LABEL: @select_ashr(
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], i128 [[Y:%.*]], i128 0, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], i128 [[Y:%.*]], i128 0, !prof [[PROF0]], !unpredictable [[META2]]
; CHECK-NEXT: [[RET:%.*]] = ashr i128 [[X:%.*]], [[OP]]
; CHECK-NEXT: ret i128 [[RET]]
;
Expand All @@ -361,7 +360,7 @@ define i128 @select_ashr(i1 %cond, i128 %x, i128 %y) {

define double @select_fmul(i1 %cond, double %x, double %y) {
; CHECK-LABEL: @select_fmul(
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], double [[Y:%.*]], double 1.000000e+00, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], double [[Y:%.*]], double 1.000000e+00, !prof [[PROF0]], !unpredictable [[META2]]
; CHECK-NEXT: [[RET:%.*]] = fmul double [[OP]], [[X:%.*]]
; CHECK-NEXT: ret double [[RET]]
;
Expand All @@ -372,7 +371,7 @@ define double @select_fmul(i1 %cond, double %x, double %y) {

define <2 x float> @select_fdiv(i1 %cond, <2 x float> %x, <2 x float> %y) {
; CHECK-LABEL: @select_fdiv(
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], <2 x float> [[Y:%.*]], <2 x float> <float 1.000000e+00, float 1.000000e+00>, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: [[OP:%.*]] = select i1 [[COND:%.*]], <2 x float> [[Y:%.*]], <2 x float> <float 1.000000e+00, float 1.000000e+00>, !prof [[PROF0]], !unpredictable [[META2]]
; CHECK-NEXT: [[RET:%.*]] = fdiv <2 x float> [[X:%.*]], [[OP]]
; CHECK-NEXT: ret <2 x float> [[RET]]
;
Expand All @@ -391,5 +390,5 @@ define <2 x float> @select_fdiv(i1 %cond, <2 x float> %x, <2 x float> %y) {
;.
; CHECK: [[PROF0]] = !{!"branch_weights", i32 2, i32 10}
; CHECK: [[PROF1]] = !{!"branch_weights", i32 10, i32 2}
; CHECK: [[META2:![0-9]+]] = !{}
; CHECK: [[META2]] = !{}
;.