[llvm] r280299 - [InstCombine] allow icmp (div X, Y), C folds for splat constant vectors
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Wed Aug 31 14:57:21 PDT 2016
Author: spatel
Date: Wed Aug 31 16:57:21 2016
New Revision: 280299
URL: http://llvm.org/viewvc/llvm-project?rev=280299&view=rev
Log:
[InstCombine] allow icmp (div X, Y), C folds for splat constant vectors
Converting all of the overflow ops to APInt looked risky, so I've left that as a TODO.
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/test/Transforms/InstCombine/2007-03-21-SignedRangeTest.ll
llvm/trunk/test/Transforms/InstCombine/div.ll
llvm/trunk/test/Transforms/InstCombine/exact.ll
llvm/trunk/test/Transforms/InstCombine/icmp.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=280299&r1=280298&r2=280299&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Wed Aug 31 16:57:21 2016
@@ -35,11 +35,6 @@ using namespace PatternMatch;
// How many times is a select replaced by one of its operands?
STATISTIC(NumSel, "Number of select opts");
-// Initialization Routines
-
-static ConstantInt *getOne(Constant *C) {
- return ConstantInt::get(cast<IntegerType>(C->getType()), 1);
-}
static ConstantInt *ExtractElement(Constant *V, Constant *Idx) {
return cast<ConstantInt>(ConstantExpr::getExtractElement(V, Idx));
@@ -2001,33 +1996,28 @@ Instruction *InstCombiner::foldICmpDivCo
assert(!(DivIsSigned && C2->isAllOnesValue()) &&
"The overflow computation will fail.");
- // FIXME: These checks restrict all folds under here to scalar types.
- ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1));
- if (!RHS)
- return nullptr;
+ // TODO: We could do all of the computations below using APInt.
+ Constant *CmpRHS = cast<Constant>(Cmp.getOperand(1));
+ Constant *DivRHS = cast<Constant>(Div->getOperand(1));
+
+ // Compute Prod = CmpRHS * DivRHS. We are essentially solving an equation of
+ // form X / C2 = C. We solve for X by multiplying C2 (DivRHS) and C (CmpRHS).
+ // By solving for X, we can turn this into a range check instead of computing
+ // a divide.
+ Constant *Prod = ConstantExpr::getMul(CmpRHS, DivRHS);
+
+ // Determine if the product overflows by seeing if the product is not equal to
+ // the divide. Make sure we do the same kind of divide as in the LHS
+ // instruction that we're folding.
+ bool ProdOV = (DivIsSigned ? ConstantExpr::getSDiv(Prod, DivRHS)
+ : ConstantExpr::getUDiv(Prod, DivRHS)) != CmpRHS;
- ConstantInt *DivRHS = dyn_cast<ConstantInt>(Div->getOperand(1));
- if (!DivRHS)
- return nullptr;
-
- // Compute Prod = CI * DivRHS. We are essentially solving an equation
- // of form X/C2=C. We solve for X by multiplying C2 (DivRHS) and
- // C (CI). By solving for X we can turn this into a range check
- // instead of computing a divide.
- Constant *Prod = ConstantExpr::getMul(RHS, DivRHS);
-
- // Determine if the product overflows by seeing if the product is
- // not equal to the divide. Make sure we do the same kind of divide
- // as in the LHS instruction that we're folding.
- bool ProdOV = (DivIsSigned ? ConstantExpr::getSDiv(Prod, DivRHS) :
- ConstantExpr::getUDiv(Prod, DivRHS)) != RHS;
-
- // Get the ICmp opcode
ICmpInst::Predicate Pred = Cmp.getPredicate();
// If the division is known to be exact, then there is no remainder from the
// divide, so the covered range size is unit, otherwise it is the divisor.
- ConstantInt *RangeSize = Div->isExact() ? getOne(Prod) : DivRHS;
+ Constant *RangeSize =
+ Div->isExact() ? ConstantInt::get(Div->getType(), 1) : DivRHS;
// Figure out the interval that is being checked. For example, a comparison
// like "X /u 5 == 0" is really checking that X is in the interval [0, 5).
@@ -2048,7 +2038,7 @@ Instruction *InstCombiner::foldICmpDivCo
// to the same result value.
HiOverflow = AddWithOverflow(HiBound, LoBound, RangeSize, false);
}
- } else if (DivRHS->getValue().isStrictlyPositive()) { // Divisor is > 0.
+ } else if (C2->isStrictlyPositive()) { // Divisor is > 0.
if (*C == 0) { // (X / pos) op 0
// Can't overflow. e.g. X/2 op 0 --> [-1, 2)
LoBound = ConstantExpr::getNeg(SubOne(RangeSize));
@@ -2063,17 +2053,17 @@ Instruction *InstCombiner::foldICmpDivCo
HiBound = AddOne(Prod);
LoOverflow = HiOverflow = ProdOV ? -1 : 0;
if (!LoOverflow) {
- ConstantInt *DivNeg =cast<ConstantInt>(ConstantExpr::getNeg(RangeSize));
+ Constant *DivNeg = ConstantExpr::getNeg(RangeSize);
LoOverflow = AddWithOverflow(LoBound, HiBound, DivNeg, true) ? -1 : 0;
}
}
- } else if (DivRHS->isNegative()) { // Divisor is < 0.
+ } else if (C2->isNegative()) { // Divisor is < 0.
if (Div->isExact())
- RangeSize = cast<ConstantInt>(ConstantExpr::getNeg(RangeSize));
+ RangeSize = ConstantExpr::getNeg(RangeSize);
if (*C == 0) { // (X / neg) op 0
// e.g. X/-5 op 0 --> [-4, 5)
LoBound = AddOne(RangeSize);
- HiBound = cast<ConstantInt>(ConstantExpr::getNeg(RangeSize));
+ HiBound = ConstantExpr::getNeg(RangeSize);
if (HiBound == DivRHS) { // -INTMIN = INTMIN
HiOverflow = 1; // [INTMIN+1, overflow)
HiBound = nullptr; // e.g. X/INTMIN = 0 --> X > INTMIN
@@ -2108,9 +2098,8 @@ Instruction *InstCombiner::foldICmpDivCo
return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SLT :
ICmpInst::ICMP_ULT, X, HiBound);
return replaceInstUsesWith(
- Cmp, insertRangeTest(X, cast<ConstantInt>(LoBound)->getValue(),
- cast<ConstantInt>(HiBound)->getValue(),
- DivIsSigned, true));
+ Cmp, insertRangeTest(X, LoBound->getUniqueInteger(),
+ HiBound->getUniqueInteger(), DivIsSigned, true));
case ICmpInst::ICMP_NE:
if (LoOverflow && HiOverflow)
return replaceInstUsesWith(Cmp, Builder->getTrue());
@@ -2120,10 +2109,10 @@ Instruction *InstCombiner::foldICmpDivCo
if (LoOverflow)
return new ICmpInst(DivIsSigned ? ICmpInst::ICMP_SGE :
ICmpInst::ICMP_UGE, X, HiBound);
- return replaceInstUsesWith(
- Cmp, insertRangeTest(X, cast<ConstantInt>(LoBound)->getValue(),
- cast<ConstantInt>(HiBound)->getValue(),
- DivIsSigned, false));
+ return replaceInstUsesWith(Cmp,
+ insertRangeTest(X, LoBound->getUniqueInteger(),
+ HiBound->getUniqueInteger(),
+ DivIsSigned, false));
case ICmpInst::ICMP_ULT:
case ICmpInst::ICMP_SLT:
if (LoOverflow == +1) // Low bound is greater than input range.
Modified: llvm/trunk/test/Transforms/InstCombine/2007-03-21-SignedRangeTest.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/2007-03-21-SignedRangeTest.ll?rev=280299&r1=280298&r2=280299&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/2007-03-21-SignedRangeTest.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/2007-03-21-SignedRangeTest.ll Wed Aug 31 16:57:21 2016
@@ -14,11 +14,10 @@ define i1 @test(i32 %tmp6) {
ret i1 %1
}
-; FIXME: Vectors should fold the same way.
define <2 x i1> @test_vec(<2 x i32> %tmp6) {
; CHECK-LABEL: @test_vec(
-; CHECK-NEXT: [[TMP7:%.*]] = sdiv <2 x i32> %tmp6, <i32 12, i32 12>
-; CHECK-NEXT: [[TMP1:%.*]] = icmp ne <2 x i32> [[TMP7]], <i32 -6, i32 -6>
+; CHECK-NEXT: [[TMP6_OFF:%.*]] = add <2 x i32> %tmp6, <i32 83, i32 83>
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt <2 x i32> [[TMP6_OFF]], <i32 11, i32 11>
; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%tmp7 = sdiv <2 x i32> %tmp6, <i32 12, i32 12>
Modified: llvm/trunk/test/Transforms/InstCombine/div.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/div.ll?rev=280299&r1=280298&r2=280299&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/div.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/div.ll Wed Aug 31 16:57:21 2016
@@ -72,12 +72,11 @@ define i1 @test7(i32 %A) {
ret i1 %C
}
-; FIXME: Vectors should fold the same way.
define <2 x i1> @test7vec(<2 x i32> %A) {
; CHECK-LABEL: @test7vec(
-; CHECK-NEXT: [[B:%.*]] = udiv <2 x i32> %A, <i32 10, i32 10>
-; CHECK-NEXT: [[C:%.*]] = icmp eq <2 x i32> [[B]], <i32 2, i32 2>
-; CHECK-NEXT: ret <2 x i1> [[C]]
+; CHECK-NEXT: [[A_OFF:%.*]] = add <2 x i32> %A, <i32 -20, i32 -20>
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i32> [[A_OFF]], <i32 10, i32 10>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%B = udiv <2 x i32> %A, <i32 10, i32 10>
%C = icmp eq <2 x i32> %B, <i32 2, i32 2>
@@ -95,11 +94,9 @@ define i1 @test8(i8 %A) {
ret i1 %C
}
-; FIXME: Vectors should fold the same way.
define <2 x i1> @test8vec(<2 x i8> %A) {
; CHECK-LABEL: @test8vec(
-; CHECK-NEXT: [[B:%.*]] = udiv <2 x i8> %A, <i8 123, i8 123>
-; CHECK-NEXT: [[C:%.*]] = icmp eq <2 x i8> [[B]], <i8 2, i8 2>
+; CHECK-NEXT: [[C:%.*]] = icmp ugt <2 x i8> %A, <i8 -11, i8 -11>
; CHECK-NEXT: ret <2 x i1> [[C]]
;
%B = udiv <2 x i8> %A, <i8 123, i8 123>
@@ -118,11 +115,9 @@ define i1 @test9(i8 %A) {
ret i1 %C
}
-; FIXME: Vectors should fold the same way.
define <2 x i1> @test9vec(<2 x i8> %A) {
; CHECK-LABEL: @test9vec(
-; CHECK-NEXT: [[B:%.*]] = udiv <2 x i8> %A, <i8 123, i8 123>
-; CHECK-NEXT: [[C:%.*]] = icmp ne <2 x i8> [[B]], <i8 2, i8 2>
+; CHECK-NEXT: [[C:%.*]] = icmp ult <2 x i8> %A, <i8 -10, i8 -10>
; CHECK-NEXT: ret <2 x i1> [[C]]
;
%B = udiv <2 x i8> %A, <i8 123, i8 123>
Modified: llvm/trunk/test/Transforms/InstCombine/exact.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/exact.ll?rev=280299&r1=280298&r2=280299&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/exact.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/exact.ll Wed Aug 31 16:57:21 2016
@@ -159,8 +159,8 @@ define i1 @udiv_icmp1(i64 %X) {
define <2 x i1> @udiv_icmp1_vec(<2 x i64> %X) {
; CHECK-LABEL: @udiv_icmp1_vec(
-; CHECK-NEXT: [[B:%.*]] = icmp ugt <2 x i64> %X, <i64 4, i64 4>
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ne <2 x i64> %X, zeroinitializer
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = udiv exact <2 x i64> %X, <i64 5, i64 5>
%B = icmp ne <2 x i64> %A, zeroinitializer
@@ -177,10 +177,11 @@ define i1 @udiv_icmp2(i64 %X) {
ret i1 %B
}
+; FIXME: missing vector fold for ult 1 -> eq 0
define <2 x i1> @udiv_icmp2_vec(<2 x i64> %X) {
; CHECK-LABEL: @udiv_icmp2_vec(
-; CHECK-NEXT: [[B:%.*]] = icmp ult <2 x i64> %X, <i64 5, i64 5>
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i64> %X, <i64 1, i64 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = udiv exact <2 x i64> %X, <i64 5, i64 5>
%B = icmp eq <2 x i64> %A, zeroinitializer
@@ -197,12 +198,11 @@ define i1 @sdiv_icmp1(i64 %X) {
ret i1 %B
}
-; FIXME: Vectors should fold too.
+; FIXME: missing vector fold for ult 1 -> eq 0
define <2 x i1> @sdiv_icmp1_vec(<2 x i64> %X) {
; CHECK-LABEL: @sdiv_icmp1_vec(
-; CHECK-NEXT: [[A:%.*]] = sdiv exact <2 x i64> %X, <i64 5, i64 5>
-; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i64> [[A]], zeroinitializer
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i64> %X, <i64 1, i64 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = sdiv exact <2 x i64> %X, <i64 5, i64 5>
%B = icmp eq <2 x i64> %A, zeroinitializer
@@ -219,12 +219,10 @@ define i1 @sdiv_icmp2(i64 %X) {
ret i1 %B
}
-; FIXME: Vectors should fold too.
define <2 x i1> @sdiv_icmp2_vec(<2 x i64> %X) {
; CHECK-LABEL: @sdiv_icmp2_vec(
-; CHECK-NEXT: [[A:%.*]] = sdiv exact <2 x i64> %X, <i64 5, i64 5>
-; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i64> [[A]], <i64 1, i64 1>
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq <2 x i64> %X, <i64 5, i64 5>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = sdiv exact <2 x i64> %X, <i64 5, i64 5>
%B = icmp eq <2 x i64> %A, <i64 1, i64 1>
@@ -241,12 +239,10 @@ define i1 @sdiv_icmp3(i64 %X) {
ret i1 %B
}
-; FIXME: Vectors should fold too.
define <2 x i1> @sdiv_icmp3_vec(<2 x i64> %X) {
; CHECK-LABEL: @sdiv_icmp3_vec(
-; CHECK-NEXT: [[A:%.*]] = sdiv exact <2 x i64> %X, <i64 5, i64 5>
-; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i64> [[A]], <i64 -1, i64 -1>
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq <2 x i64> %X, <i64 -5, i64 -5>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = sdiv exact <2 x i64> %X, <i64 5, i64 5>
%B = icmp eq <2 x i64> %A, <i64 -1, i64 -1>
@@ -263,12 +259,11 @@ define i1 @sdiv_icmp4(i64 %X) {
ret i1 %B
}
-; FIXME: Vectors should fold too.
+; FIXME: missing vector fold for ult 1 -> eq 0
define <2 x i1> @sdiv_icmp4_vec(<2 x i64> %X) {
; CHECK-LABEL: @sdiv_icmp4_vec(
-; CHECK-NEXT: [[A:%.*]] = sdiv exact <2 x i64> %X, <i64 -5, i64 -5>
-; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i64> [[A]], zeroinitializer
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i64> %X, <i64 1, i64 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = sdiv exact <2 x i64> %X, <i64 -5, i64 -5>
%B = icmp eq <2 x i64> %A, zeroinitializer
@@ -285,12 +280,10 @@ define i1 @sdiv_icmp5(i64 %X) {
ret i1 %B
}
-; FIXME: Vectors should fold too.
define <2 x i1> @sdiv_icmp5_vec(<2 x i64> %X) {
; CHECK-LABEL: @sdiv_icmp5_vec(
-; CHECK-NEXT: [[A:%.*]] = sdiv exact <2 x i64> %X, <i64 -5, i64 -5>
-; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i64> [[A]], <i64 1, i64 1>
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq <2 x i64> %X, <i64 -5, i64 -5>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = sdiv exact <2 x i64> %X, <i64 -5, i64 -5>
%B = icmp eq <2 x i64> %A, <i64 1, i64 1>
@@ -307,12 +300,10 @@ define i1 @sdiv_icmp6(i64 %X) {
ret i1 %B
}
-; FIXME: Vectors should fold too.
define <2 x i1> @sdiv_icmp6_vec(<2 x i64> %X) {
; CHECK-LABEL: @sdiv_icmp6_vec(
-; CHECK-NEXT: [[A:%.*]] = sdiv exact <2 x i64> %X, <i64 -5, i64 -5>
-; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i64> [[A]], <i64 -1, i64 -1>
-; CHECK-NEXT: ret <2 x i1> [[B]]
+; CHECK-NEXT: [[TMP1:%.*]] = icmp eq <2 x i64> %X, <i64 5, i64 5>
+; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%A = sdiv exact <2 x i64> %X, <i64 -5, i64 -5>
%B = icmp eq <2 x i64> %A, <i64 -1, i64 -1>
Modified: llvm/trunk/test/Transforms/InstCombine/icmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/icmp.ll?rev=280299&r1=280298&r2=280299&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/icmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/icmp.ll Wed Aug 31 16:57:21 2016
@@ -282,11 +282,9 @@ define i1 @test23(i32 %x) {
ret i1 %i4
}
-; FIXME: Vectors should fold too.
define <2 x i1> @test23vec(<2 x i32> %x) {
; CHECK-LABEL: @test23vec(
-; CHECK-NEXT: [[I3:%.*]] = sdiv <2 x i32> %x, <i32 -1328634635, i32 -1328634635>
-; CHECK-NEXT: [[I4:%.*]] = icmp eq <2 x i32> [[I3]], <i32 -1, i32 -1>
+; CHECK-NEXT: [[I4:%.*]] = icmp sgt <2 x i32> %x, <i32 1328634634, i32 1328634634>
; CHECK-NEXT: ret <2 x i1> [[I4]]
;
%i3 = sdiv <2 x i32> %x, <i32 -1328634635, i32 -1328634635>
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