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[InstCombine] Fold Select with AND/OR condition 

Summary:
Fold
```
%A = icmp ne i8 %X, %V1
%B = icmp ne i8 %X, %V2
%C = or i1 %A, %B
%D = select i1 %C, i8 %X, i8 %V1
ret i8 %D
  =>
ret i8 %X

Fixes https://bugs.llvm.org/show_bug.cgi?id=38334
Proof: https://rise4fun.com/Alive/plI8

Reviewers: spatel, lebedev.ri

Reviewed By: lebedev.ri

Subscribers: craig.topper, llvm-commits

Differential Revision: https://reviews.llvm.org/D49919

llvm-svn: 338191
This commit is contained in:
David Bolvansky 2018-07-28 06:55:51 +00:00
parent 256db4b799
commit f947608ddf
3 changed files with 47 additions and 50 deletions
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37
llvm/lib/Analysis/InstructionSimplify.cpp
View File

@ -65,6 +65,40 @@ static Value *SimplifyCastInst(unsigned, Value *, Type *,
static Value *SimplifyGEPInst(Type *, ArrayRef<Value *>, const SimplifyQuery &,
unsigned);
/// Fold
/// %A = icmp ne/eq i8 %X, %V1
/// %B = icmp ne/eq i8 %X, %V2
/// %C = or/and i1 %A, %B
/// %D = select i1 %C, i8 %X, i8 %V1
/// To
/// %X/%V1
static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal,
Value *FalseVal) {
BinaryOperator::BinaryOps BinOpCode;
if (auto *BO = dyn_cast<BinaryOperator>(Cond))
BinOpCode = BO->getOpcode();
else
return nullptr;
CmpInst::Predicate ExpectedPred;
if (BinOpCode == BinaryOperator::Or) {
ExpectedPred = ICmpInst::ICMP_NE;
} else if (BinOpCode == BinaryOperator::And) {
ExpectedPred = ICmpInst::ICMP_EQ;
} else
return nullptr;
CmpInst::Predicate Pred1, Pred2;
if (!match(
Cond,
m_c_BinOp(m_c_ICmp(Pred1, m_Specific(TrueVal), m_Specific(FalseVal)),
m_c_ICmp(Pred2, m_Specific(TrueVal), m_Value()))) ||
Pred1 != Pred2 || Pred1 != ExpectedPred)
return nullptr;
return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal;
}
/// For a boolean type or a vector of boolean type, return false or a vector
/// with every element false.
static Constant *getFalse(Type *Ty) {
@ -3752,6 +3786,9 @@ static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse))
return V;
if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal))
return V;
return nullptr;
}

30
llvm/test/Transforms/InstCombine/select-and-cmp.ll
View File

@ -5,11 +5,7 @@ target triple = "x86_64-unknown-linux-gnu"
define i32 @select_and_icmp(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp eq i32 %y, %z
@ -20,11 +16,7 @@ define i32 @select_and_icmp(i32 %x, i32 %y, i32 %z) {
define <2 x i8> @select_and_icmp_vec(<2 x i8> %x, <2 x i8> %y, <2 x i8> %z) {
; CHECK-LABEL: @select_and_icmp_vec(
; CHECK-NEXT: [[A:%.*]] = icmp eq <2 x i8> [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq <2 x i8> [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and <2 x i1> [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select <2 x i1> [[C]], <2 x i8> [[Z]], <2 x i8> [[X]]
; CHECK-NEXT: ret <2 x i8> [[D]]
; CHECK-NEXT: ret <2 x i8> [[X:%.*]]
;
%A = icmp eq <2 x i8> %x, %z
%B = icmp eq <2 x i8> %y, %z
@ -35,11 +27,7 @@ define <2 x i8> @select_and_icmp_vec(<2 x i8> %x, <2 x i8> %y, <2 x i8> %z) {
define i32 @select_and_icmp2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp2(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[Y]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[Y:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp eq i32 %y, %z
@ -50,11 +38,7 @@ define i32 @select_and_icmp2(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_inv_icmp(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_inv_icmp(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[B]], [[A]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp eq i32 %x, %z
%B = icmp eq i32 %y, %z
@ -65,11 +49,7 @@ define i32 @select_and_inv_icmp(i32 %x, i32 %y, i32 %z) {
define i32 @select_and_icmp_inv(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_and_icmp_inv(
; CHECK-NEXT: [[A:%.*]] = icmp eq i32 [[Z:%.*]], [[X:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp eq i32 [[Z]], [[Y:%.*]]
; CHECK-NEXT: [[C:%.*]] = and i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[X:%.*]]
;
%A = icmp eq i32 %z, %x
%B = icmp eq i32 %z, %y

30
llvm/test/Transforms/InstCombine/select-or-cmp.ll
View File

@ -5,11 +5,7 @@ target triple = "x86_64-unknown-linux-gnu"
define i32 @select_or_icmp(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp ne i32 %y, %z
@ -20,11 +16,7 @@ define i32 @select_or_icmp(i32 %x, i32 %y, i32 %z) {
define <2 x i8> @select_or_icmp_vec(<2 x i8> %x, <2 x i8> %y, <2 x i8> %z) {
; CHECK-LABEL: @select_or_icmp_vec(
; CHECK-NEXT: [[A:%.*]] = icmp ne <2 x i8> [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne <2 x i8> [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or <2 x i1> [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select <2 x i1> [[C]], <2 x i8> [[Z]], <2 x i8> [[X]]
; CHECK-NEXT: ret <2 x i8> [[D]]
; CHECK-NEXT: ret <2 x i8> [[Z:%.*]]
;
%A = icmp ne <2 x i8> %x, %z
%B = icmp ne <2 x i8> %y, %z
@ -35,11 +27,7 @@ define <2 x i8> @select_or_icmp_vec(<2 x i8> %x, <2 x i8> %y, <2 x i8> %z) {
define i32 @select_or_icmp2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp2(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[Y]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp ne i32 %y, %z
@ -50,11 +38,7 @@ define i32 @select_or_icmp2(i32 %x, i32 %y, i32 %z) {
define i32 @select_or_inv_icmp(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_inv_icmp(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[X:%.*]], [[Z:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Y:%.*]], [[Z]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[B]], [[A]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp ne i32 %x, %z
%B = icmp ne i32 %y, %z
@ -65,11 +49,7 @@ define i32 @select_or_inv_icmp(i32 %x, i32 %y, i32 %z) {
define i32 @select_or_icmp_inv(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @select_or_icmp_inv(
; CHECK-NEXT: [[A:%.*]] = icmp ne i32 [[Z:%.*]], [[X:%.*]]
; CHECK-NEXT: [[B:%.*]] = icmp ne i32 [[Z]], [[Y:%.*]]
; CHECK-NEXT: [[C:%.*]] = or i1 [[A]], [[B]]
; CHECK-NEXT: [[D:%.*]] = select i1 [[C]], i32 [[Z]], i32 [[X]]
; CHECK-NEXT: ret i32 [[D]]
; CHECK-NEXT: ret i32 [[Z:%.*]]
;
%A = icmp ne i32 %z, %x
%B = icmp ne i32 %z, %y