[InstCombine] Try to reuse constant from select in leading comparison

Summary:
If we have e.g.:
```
  %t = icmp ult i32 %x, 65536
  %r = select i1 %t, i32 %y, i32 65535
```
the constants `65535` and `65536` are suspiciously close.
We could perform a transformation to deduplicate them:
```
Name: ult
%t = icmp ult i32 %x, 65536
%r = select i1 %t, i32 %y, i32 65535
  =>
%t.inv = icmp ugt i32 %x, 65535
%r = select i1 %t.inv, i32 65535, i32 %y
```
https://rise4fun.com/Alive/avb

While this may seem esoteric, this should certainly be good for vectors
(less constant pool usage) and for opt-for-size - need to have only one constant.

But the real fun part here is that it allows further transformation,
in particular it finishes cleaning up the `clamp` folding,
see e.g. `canonicalize-clamp-with-select-of-constant-threshold-pattern.ll`.
We start with e.g.
```
  %dont_need_to_clamp_positive = icmp sle i32 %X, 32767
  %dont_need_to_clamp_negative = icmp sge i32 %X, -32768
  %clamp_limit = select i1 %dont_need_to_clamp_positive, i32 -32768, i32 32767
  %dont_need_to_clamp = and i1 %dont_need_to_clamp_positive, %dont_need_to_clamp_negative
  %R = select i1 %dont_need_to_clamp, i32 %X, i32 %clamp_limit
```
without this patch we currently produce
```
  %1 = icmp slt i32 %X, 32768
  %2 = icmp sgt i32 %X, -32768
  %3 = select i1 %2, i32 %X, i32 -32768
  %R = select i1 %1, i32 %3, i32 32767
```
which isn't really a `clamp` - both comparisons are performed on the original value,
this patch changes it into
```
  %1.inv = icmp sgt i32 %X, 32767
  %2 = icmp sgt i32 %X, -32768
  %3 = select i1 %2, i32 %X, i32 -32768
  %R = select i1 %1.inv, i32 32767, i32 %3
```
and then the magic happens! Some further transform finishes polishing it and we finally get:
```
  %t1 = icmp sgt i32 %X, -32768
  %t2 = select i1 %t1, i32 %X, i32 -32768
  %t3 = icmp slt i32 %t2, 32767
  %R = select i1 %t3, i32 %t2, i32 32767
```
which is beautiful and just what we want.

Proofs for `getFlippedStrictnessPredicateAndConstant()` for de-canonicalization:
https://rise4fun.com/Alive/THl
Proofs for the fold itself: https://rise4fun.com/Alive/THl

Reviewers: spatel, dmgreen, nikic, xbolva00

Reviewed By: spatel

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66232

llvm-svn: 369840
This commit is contained in:
Roman Lebedev 2019-08-24 06:49:25 +00:00
parent 190850ddfb
commit c7933992b4
6 changed files with 197 additions and 89 deletions

View File

@ -4912,20 +4912,27 @@ llvm::Optional<std::pair<CmpInst::Predicate, Constant *>>
llvm::getFlippedStrictnessPredicateAndConstant(CmpInst::Predicate Pred,
Constant *C) {
assert(ICmpInst::isRelational(Pred) && ICmpInst::isIntPredicate(Pred) &&
!isCanonicalPredicate(Pred) &&
"Only for non-canonical relational integer predicates.");
"Only for relational integer predicates.");
// Check if the constant operand can be safely incremented/decremented without
// overflowing/underflowing. For scalars, SimplifyICmpInst should have already
// handled the edge cases for us, so we just assert on them.
// For vectors, we must handle the edge cases.
Type *Type = C->getType();
bool IsSigned = ICmpInst::isSigned(Pred);
bool IsLE = (Pred == ICmpInst::ICMP_SLE || Pred == ICmpInst::ICMP_ULE);
auto *CI = dyn_cast<ConstantInt>(C);
if (CI) {
CmpInst::Predicate UnsignedPred = ICmpInst::getUnsignedPredicate(Pred);
bool WillIncrement =
UnsignedPred == ICmpInst::ICMP_ULE || UnsignedPred == ICmpInst::ICMP_UGT;
// Check if the constant operand can be safely incremented/decremented
// without overflowing/underflowing.
auto ConstantIsOk = [WillIncrement, IsSigned](ConstantInt *C) {
return WillIncrement ? !C->isMaxValue(IsSigned) : !C->isMinValue(IsSigned);
};
// For scalars, SimplifyICmpInst should have already handled
// the edge cases for us, so we just assert on them.
// For vectors, we must handle the edge cases.
if (auto *CI = dyn_cast<ConstantInt>(C)) {
// A <= MAX -> TRUE ; A >= MIN -> TRUE
assert(IsLE ? !CI->isMaxValue(IsSigned) : !CI->isMinValue(IsSigned));
assert(ConstantIsOk(CI));
} else if (Type->isVectorTy()) {
// TODO? If the edge cases for vectors were guaranteed to be handled as they
// are for scalar, we could remove the min/max checks. However, to do that,
@ -4942,7 +4949,7 @@ llvm::getFlippedStrictnessPredicateAndConstant(CmpInst::Predicate Pred,
// Bail out if we can't determine if this constant is min/max or if we
// know that this constant is min/max.
auto *CI = dyn_cast<ConstantInt>(Elt);
if (!CI || (IsLE ? CI->isMaxValue(IsSigned) : CI->isMinValue(IsSigned)))
if (!CI || !ConstantIsOk(CI))
return llvm::None;
}
} else {
@ -4953,7 +4960,7 @@ llvm::getFlippedStrictnessPredicateAndConstant(CmpInst::Predicate Pred,
CmpInst::Predicate NewPred = CmpInst::getFlippedStrictnessPredicate(Pred);
// Increment or decrement the constant.
Constant *OneOrNegOne = ConstantInt::get(Type, IsLE ? 1 : -1, true);
Constant *OneOrNegOne = ConstantInt::get(Type, WillIncrement ? 1 : -1, true);
Constant *NewC = ConstantExpr::getAdd(C, OneOrNegOne);
return std::make_pair(NewPred, NewC);

View File

@ -1261,6 +1261,95 @@ static Instruction *canonicalizeClampLike(SelectInst &Sel0, ICmpInst &Cmp0,
return MaybeReplacedHigh;
}
// If we have
// %cmp = icmp [canonical predicate] i32 %x, C0
// %r = select i1 %cmp, i32 %y, i32 C1
// Where C0 != C1 and %x may be different from %y, see if the constant that we
// will have if we flip the strictness of the predicate (i.e. without changing
// the result) is identical to the C1 in select. If it matches we can change
// original comparison to one with swapped predicate, reuse the constant,
// and swap the hands of select.
static Instruction *
tryToReuseConstantFromSelectInComparison(SelectInst &Sel, ICmpInst &Cmp,
InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate Pred;
Value *X;
Constant *C0;
if (!match(&Cmp, m_OneUse(m_ICmp(
Pred, m_Value(X),
m_CombineAnd(m_AnyIntegralConstant(), m_Constant(C0))))))
return nullptr;
// If comparison predicate is non-relational, we won't be able to do anything.
if (ICmpInst::isEquality(Pred))
return nullptr;
// If comparison predicate is non-canonical, then we certainly won't be able
// to make it canonical; canonicalizeCmpWithConstant() already tried.
if (!isCanonicalPredicate(Pred))
return nullptr;
// If the [input] type of comparison and select type are different, lets abort
// for now. We could try to compare constants with trunc/[zs]ext though.
if (C0->getType() != Sel.getType())
return nullptr;
// FIXME: are there any magic icmp predicate+constant pairs we must not touch?
auto ConstantsAreElementWiseEqual = [](Constant *Cx, Value *Y) {
// Are they fully identical?
if (Cx == Y)
return true;
// They may still be identical element-wise (if they have `undef`s).
auto *Cy = dyn_cast<Constant>(Y);
if (!Cy)
return false;
return match(ConstantExpr::getICmp(ICmpInst::Predicate::ICMP_EQ, Cx, Cy),
m_One());
};
Value *SelVal0, *SelVal1; // We do not care which one is from where.
match(&Sel, m_Select(m_Value(), m_Value(SelVal0), m_Value(SelVal1)));
// At least one of these values we are selecting between must be a constant
// else we'll never succeed.
if (!match(SelVal0, m_AnyIntegralConstant()) &&
!match(SelVal1, m_AnyIntegralConstant()))
return nullptr;
// Does this constant C match any of the `select` values?
auto MatchesSelectValue = [ConstantsAreElementWiseEqual, SelVal0,
SelVal1](Constant *C) {
return ConstantsAreElementWiseEqual(C, SelVal0) ||
ConstantsAreElementWiseEqual(C, SelVal1);
};
// If C0 *already* matches true/false value of select, we are done.
if (MatchesSelectValue(C0))
return nullptr;
// Check the constant we'd have with flipped-strictness predicate.
auto FlippedStrictness = getFlippedStrictnessPredicateAndConstant(Pred, C0);
if (!FlippedStrictness)
return nullptr;
// If said constant doesn't match either, then there is no hope,
if (!MatchesSelectValue(FlippedStrictness->second))
return nullptr;
// It matched! Lets insert the new comparison just before select.
InstCombiner::BuilderTy::InsertPointGuard Guard(Builder);
Builder.SetInsertPoint(&Sel);
Pred = ICmpInst::getSwappedPredicate(Pred); // Yes, swapped.
Value *NewCmp = Builder.CreateICmp(Pred, X, FlippedStrictness->second,
Cmp.getName() + ".inv");
Sel.setCondition(NewCmp);
Sel.swapValues();
Sel.swapProfMetadata();
return &Sel;
}
/// Visit a SelectInst that has an ICmpInst as its first operand.
Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
ICmpInst *ICI) {
@ -1276,6 +1365,10 @@ Instruction *InstCombiner::foldSelectInstWithICmp(SelectInst &SI,
if (Instruction *NewAbs = canonicalizeClampLike(SI, *ICI, Builder))
return NewAbs;
if (Instruction *NewSel =
tryToReuseConstantFromSelectInComparison(SI, *ICI, Builder))
return NewSel;
bool Changed = adjustMinMax(SI, *ICI);
if (Value *V = foldSelectICmpAnd(SI, ICI, Builder))

View File

@ -7,10 +7,10 @@
define i32 @t0_select_cond_and_v0(i32 %X) {
; CHECK-LABEL: @t0_select_cond_and_v0(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP3:%.*]] = icmp slt i32 [[TMP2]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%dont_need_to_clamp_positive = icmp sle i32 %X, 32767
@ -22,10 +22,10 @@ define i32 @t0_select_cond_and_v0(i32 %X) {
}
define i32 @t1_select_cond_and_v1(i32 %X) {
; CHECK-LABEL: @t1_select_cond_and_v1(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP3:%.*]] = icmp slt i32 [[TMP2]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%dont_need_to_clamp_positive = icmp sle i32 %X, 32767
@ -40,10 +40,10 @@ define i32 @t1_select_cond_and_v1(i32 %X) {
define i32 @t2_select_cond_or_v0(i32 %X) {
; CHECK-LABEL: @t2_select_cond_or_v0(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP3:%.*]] = icmp slt i32 [[TMP2]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%need_to_clamp_positive = icmp sgt i32 %X, 32767
@ -55,10 +55,10 @@ define i32 @t2_select_cond_or_v0(i32 %X) {
}
define i32 @t3_select_cond_or_v1(i32 %X) {
; CHECK-LABEL: @t3_select_cond_or_v1(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP3:%.*]] = icmp slt i32 [[TMP2]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP3]], i32 [[TMP2]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%need_to_clamp_positive = icmp sgt i32 %X, 32767
@ -73,10 +73,10 @@ define i32 @t3_select_cond_or_v1(i32 %X) {
define i32 @t4_select_cond_xor_v0(i32 %X) {
; CHECK-LABEL: @t4_select_cond_xor_v0(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[DOTINV1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTINV1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP2]], i32 [[TMP1]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%need_to_clamp_positive = icmp sgt i32 %X, 32767
@ -88,10 +88,10 @@ define i32 @t4_select_cond_xor_v0(i32 %X) {
}
define i32 @t4_select_cond_xor_v1(i32 %X) {
; CHECK-LABEL: @t4_select_cond_xor_v1(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[DOTINV1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTINV1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP2]], i32 [[TMP1]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%need_to_clamp_positive = icmp sgt i32 %X, 32767
@ -104,10 +104,10 @@ define i32 @t4_select_cond_xor_v1(i32 %X) {
define i32 @t5_select_cond_xor_v2(i32 %X) {
; CHECK-LABEL: @t5_select_cond_xor_v2(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[DOTINV1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTINV1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP2]], i32 [[TMP1]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%dont_need_to_clamp_positive = icmp sle i32 %X, 32767
@ -119,10 +119,10 @@ define i32 @t5_select_cond_xor_v2(i32 %X) {
}
define i32 @t5_select_cond_xor_v3(i32 %X) {
; CHECK-LABEL: @t5_select_cond_xor_v3(
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[X]], -32768
; CHECK-NEXT: [[TMP3:%.*]] = select i1 [[TMP2]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP1]], i32 [[TMP3]], i32 32767
; CHECK-NEXT: [[DOTINV1:%.*]] = icmp sgt i32 [[X:%.*]], -32768
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[DOTINV1]], i32 [[X]], i32 -32768
; CHECK-NEXT: [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 32767
; CHECK-NEXT: [[R:%.*]] = select i1 [[TMP2]], i32 [[TMP1]], i32 32767
; CHECK-NEXT: ret i32 [[R]]
;
%dont_need_to_clamp_positive = icmp sle i32 %X, 32767

View File

@ -18,8 +18,8 @@
define i32 @p0_ult_65536(i32 %x, i32 %y) {
; CHECK-LABEL: @p0_ult_65536(
; CHECK-NEXT: [[T:%.*]] = icmp ult i32 [[X:%.*]], 65536
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 [[Y:%.*]], i32 65535, !prof !0
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 65535, i32 [[Y:%.*]], !prof !0
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp ult i32 %x, 65536
@ -28,8 +28,8 @@ define i32 @p0_ult_65536(i32 %x, i32 %y) {
}
define i32 @p1_ugt(i32 %x, i32 %y) {
; CHECK-LABEL: @p1_ugt(
; CHECK-NEXT: [[T:%.*]] = icmp ugt i32 [[X:%.*]], 65534
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 [[Y:%.*]], i32 65535
; CHECK-NEXT: [[T_INV:%.*]] = icmp ult i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 65535, i32 [[Y:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp ugt i32 %x, 65534
@ -38,8 +38,8 @@ define i32 @p1_ugt(i32 %x, i32 %y) {
}
define i32 @p2_slt_65536(i32 %x, i32 %y) {
; CHECK-LABEL: @p2_slt_65536(
; CHECK-NEXT: [[T:%.*]] = icmp slt i32 [[X:%.*]], 65536
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 [[Y:%.*]], i32 65535
; CHECK-NEXT: [[T_INV:%.*]] = icmp sgt i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 65535, i32 [[Y:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp slt i32 %x, 65536
@ -48,8 +48,8 @@ define i32 @p2_slt_65536(i32 %x, i32 %y) {
}
define i32 @p3_sgt(i32 %x, i32 %y) {
; CHECK-LABEL: @p3_sgt(
; CHECK-NEXT: [[T:%.*]] = icmp sgt i32 [[X:%.*]], 65534
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 [[Y:%.*]], i32 65535
; CHECK-NEXT: [[T_INV:%.*]] = icmp slt i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 65535, i32 [[Y:%.*]]
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp sgt i32 %x, 65534
@ -63,8 +63,8 @@ define i32 @p3_sgt(i32 %x, i32 %y) {
define <2 x i32> @p4_vec_splat_ult_65536(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p4_vec_splat_ult_65536(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> [[X:%.*]], <i32 65536, i32 65536>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 65535>
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 65535>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp ult <2 x i32> %x, <i32 65536, i32 65536>
@ -73,8 +73,8 @@ define <2 x i32> @p4_vec_splat_ult_65536(<2 x i32> %x, <2 x i32> %y) {
}
define <2 x i32> @p5_vec_splat_ugt(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p5_vec_splat_ugt(
; CHECK-NEXT: [[T:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65534, i32 65534>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 65535>
; CHECK-NEXT: [[T_INV:%.*]] = icmp ult <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 65535>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp ugt <2 x i32> %x, <i32 65534, i32 65534>
@ -83,8 +83,8 @@ define <2 x i32> @p5_vec_splat_ugt(<2 x i32> %x, <2 x i32> %y) {
}
define <2 x i32> @p6_vec_splat_slt_65536(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p6_vec_splat_slt_65536(
; CHECK-NEXT: [[T:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 65536, i32 65536>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 65535>
; CHECK-NEXT: [[T_INV:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 65535>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp slt <2 x i32> %x, <i32 65536, i32 65536>
@ -93,8 +93,8 @@ define <2 x i32> @p6_vec_splat_slt_65536(<2 x i32> %x, <2 x i32> %y) {
}
define <2 x i32> @p7_vec_splat_sgt(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p7_vec_splat_sgt(
; CHECK-NEXT: [[T:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 65534, i32 65534>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 65535>
; CHECK-NEXT: [[T_INV:%.*]] = icmp slt <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 65535>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp sgt <2 x i32> %x, <i32 65534, i32 65534>
@ -106,8 +106,8 @@ define <2 x i32> @p7_vec_splat_sgt(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @p8_vec_nonsplat_undef0(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p8_vec_nonsplat_undef0(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> [[X:%.*]], <i32 65536, i32 undef>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 65535>
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65535, i32 undef>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 65535>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp ult <2 x i32> %x, <i32 65536, i32 undef>
@ -116,8 +116,8 @@ define <2 x i32> @p8_vec_nonsplat_undef0(<2 x i32> %x, <2 x i32> %y) {
}
define <2 x i32> @p9_vec_nonsplat_undef1(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p9_vec_nonsplat_undef1(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> [[X:%.*]], <i32 65536, i32 65536>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 undef>
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65535, i32 65535>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 undef>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp ult <2 x i32> %x, <i32 65536, i32 65536>
@ -126,8 +126,8 @@ define <2 x i32> @p9_vec_nonsplat_undef1(<2 x i32> %x, <2 x i32> %y) {
}
define <2 x i32> @p10_vec_nonsplat_undef2(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p10_vec_nonsplat_undef2(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> [[X:%.*]], <i32 65536, i32 undef>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 undef>
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65535, i32 undef>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 undef>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp ult <2 x i32> %x, <i32 65536, i32 undef>
@ -139,8 +139,8 @@ define <2 x i32> @p10_vec_nonsplat_undef2(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @p11_vec_nonsplat(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @p11_vec_nonsplat(
; CHECK-NEXT: [[T:%.*]] = icmp ult <2 x i32> [[X:%.*]], <i32 65536, i32 32768>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T]], <2 x i32> [[Y:%.*]], <2 x i32> <i32 65535, i32 32767>
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt <2 x i32> [[X:%.*]], <i32 65535, i32 32767>
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[T_INV]], <2 x i32> <i32 65535, i32 32767>, <2 x i32> [[Y:%.*]]
; CHECK-NEXT: ret <2 x i32> [[R]]
;
%t = icmp ult <2 x i32> %x, <i32 65536, i32 32768>
@ -174,8 +174,8 @@ define i32 @n12_extrause(i32 %x, i32 %y) {
; We don't care if the constant in select is true value or false value
define i32 @p13_commutativity0(i32 %x, i32 %y) {
; CHECK-LABEL: @p13_commutativity0(
; CHECK-NEXT: [[T:%.*]] = icmp ult i32 [[X:%.*]], 65536
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 65535, i32 [[Y:%.*]]
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 [[Y:%.*]], i32 65535
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp ult i32 %x, 65536
@ -186,8 +186,8 @@ define i32 @p13_commutativity0(i32 %x, i32 %y) {
; Which means, if both possibilities are constants, we must check both of them.
define i32 @p14_commutativity1(i32 %x, i32 %y) {
; CHECK-LABEL: @p14_commutativity1(
; CHECK-NEXT: [[T:%.*]] = icmp ult i32 [[X:%.*]], 65536
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 65535, i32 42
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 42, i32 65535
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp ult i32 %x, 65536
@ -196,8 +196,8 @@ define i32 @p14_commutativity1(i32 %x, i32 %y) {
}
define i32 @p15_commutativity2(i32 %x, i32 %y) {
; CHECK-LABEL: @p15_commutativity2(
; CHECK-NEXT: [[T:%.*]] = icmp ult i32 [[X:%.*]], 65536
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 42, i32 65535
; CHECK-NEXT: [[T_INV:%.*]] = icmp ugt i32 [[X:%.*]], 65535
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 65535, i32 42
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp ult i32 %x, 65536
@ -266,8 +266,8 @@ define i32 @n21_equality(i32 %x, i32 %y) {
; There is nothing special about sign-bit-tests, we can fold them.
define i32 @t22_sign_check(i32 %x, i32 %y) {
; CHECK-LABEL: @t22_sign_check(
; CHECK-NEXT: [[T:%.*]] = icmp slt i32 [[X:%.*]], 0
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 -1, i32 [[Y:%.*]]
; CHECK-NEXT: [[T_INV:%.*]] = icmp sgt i32 [[X:%.*]], -1
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 [[Y:%.*]], i32 -1
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp slt i32 %x, 0
@ -276,8 +276,8 @@ define i32 @t22_sign_check(i32 %x, i32 %y) {
}
define i32 @t22_sign_check2(i32 %x, i32 %y) {
; CHECK-LABEL: @t22_sign_check2(
; CHECK-NEXT: [[T:%.*]] = icmp sgt i32 [[X:%.*]], -1
; CHECK-NEXT: [[R:%.*]] = select i1 [[T]], i32 0, i32 [[Y:%.*]]
; CHECK-NEXT: [[T_INV:%.*]] = icmp slt i32 [[X:%.*]], 0
; CHECK-NEXT: [[R:%.*]] = select i1 [[T_INV]], i32 [[Y:%.*]], i32 0
; CHECK-NEXT: ret i32 [[R]]
;
%t = icmp sgt i32 %x, -1
@ -333,4 +333,4 @@ define i32 @n26_all_good1(i32 %x, i32 %y) {
; CHECK: !0 = !{!"branch_weights", i32 2000, i32 1}
; CHECK: !0 = !{!"branch_weights", i32 1, i32 2000}

View File

@ -36,10 +36,14 @@ exit:
define i32 @compare_against_zero(i32 %x) {
; CHECK-LABEL: @compare_against_zero(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i32 [[X:%.*]], 0
; CHECK-NEXT: br i1 [[TMP0]], label [[CALLFOO:%.*]], label [[EXIT:%.*]]
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[X:%.*]], 0
; CHECK-NEXT: [[CMP2_INV:%.*]] = icmp sgt i32 [[X]], -1
; CHECK-NEXT: [[SELECT1:%.*]] = select i1 [[CMP2_INV]], i32 1, i32 -1
; CHECK-NEXT: [[SELECT2:%.*]] = select i1 [[CMP1]], i32 0, i32 [[SELECT1]]
; CHECK-NEXT: [[COND:%.*]] = icmp sgt i32 [[SELECT2]], 0
; CHECK-NEXT: br i1 [[COND]], label [[CALLFOO:%.*]], label [[EXIT:%.*]]
; CHECK: callfoo:
; CHECK-NEXT: call void @foo(i32 1)
; CHECK-NEXT: call void @foo(i32 [[SELECT2]])
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: ret i32 42
@ -92,10 +96,14 @@ exit:
define i32 @compare_against_two(i32 %x) {
; CHECK-LABEL: @compare_against_two(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP0:%.*]] = icmp sgt i32 [[X:%.*]], 2
; CHECK-NEXT: br i1 [[TMP0]], label [[CALLFOO:%.*]], label [[EXIT:%.*]]
; CHECK-NEXT: [[CMP1:%.*]] = icmp eq i32 [[X:%.*]], 2
; CHECK-NEXT: [[CMP2_INV:%.*]] = icmp sgt i32 [[X]], 1
; CHECK-NEXT: [[SELECT1:%.*]] = select i1 [[CMP2_INV]], i32 1, i32 -1
; CHECK-NEXT: [[SELECT2:%.*]] = select i1 [[CMP1]], i32 0, i32 [[SELECT1]]
; CHECK-NEXT: [[COND:%.*]] = icmp sgt i32 [[SELECT2]], 0
; CHECK-NEXT: br i1 [[COND]], label [[CALLFOO:%.*]], label [[EXIT:%.*]]
; CHECK: callfoo:
; CHECK-NEXT: call void @foo(i32 1)
; CHECK-NEXT: call void @foo(i32 [[SELECT2]])
; CHECK-NEXT: br label [[EXIT]]
; CHECK: exit:
; CHECK-NEXT: ret i32 42

View File

@ -7,8 +7,8 @@
; %cond0 is extra-used in select, which is freely invertible.
define i1 @v0_select_of_consts(i32 %X, i32* %selected) {
; CHECK-LABEL: @v0_select_of_consts(
; CHECK-NEXT: [[COND0:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND0]], i32 -32768, i32 32767
; CHECK-NEXT: [[COND0_INV:%.*]] = icmp sgt i32 [[X:%.*]], 32767
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND0_INV]], i32 32767, i32 -32768
; CHECK-NEXT: store i32 [[SELECT]], i32* [[SELECTED:%.*]], align 4
; CHECK-NEXT: [[X_OFF:%.*]] = add i32 [[X]], 32767
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[X_OFF]], 65535
@ -39,8 +39,8 @@ define i1 @v1_select_of_var_and_const(i32 %X, i32 %Y, i32* %selected) {
}
define i1 @v2_select_of_const_and_var(i32 %X, i32 %Y, i32* %selected) {
; CHECK-LABEL: @v2_select_of_const_and_var(
; CHECK-NEXT: [[COND0:%.*]] = icmp slt i32 [[X:%.*]], 32768
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND0]], i32 [[Y:%.*]], i32 32767
; CHECK-NEXT: [[COND0_INV:%.*]] = icmp sgt i32 [[X:%.*]], 32767
; CHECK-NEXT: [[SELECT:%.*]] = select i1 [[COND0_INV]], i32 32767, i32 [[Y:%.*]]
; CHECK-NEXT: store i32 [[SELECT]], i32* [[SELECTED:%.*]], align 4
; CHECK-NEXT: [[X_OFF:%.*]] = add i32 [[X]], 32767
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i32 [[X_OFF]], 65535