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[InstCombine] Fold two select patterns into or-and
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This patch is the follow-up improvement of D122152.
Fixes #64558.

`select (a | c), a, b -> select a, true, (select ~c, b, false)` where `c` is free to invert
`select (c & ~b), a, b -> select b, true, (select c, a, false)`
Alive2: https://alive2.llvm.org/ce/z/KwxtMA

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D158983
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@dtcxzyw
dtcxzyw committed Aug 29, 2023
1 parent adea7e7 commit 074f23e
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Showing 2 changed files with 136 additions and 42 deletions.
13 changes: 13 additions & 0 deletions llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3083,6 +3083,19 @@ Instruction *InstCombinerImpl::foldSelectOfBools(SelectInst &SI) {
TrueVal = Builder.CreateFreeze(TrueVal);
return BinaryOperator::CreateAnd(FalseVal, Builder.CreateOr(C, TrueVal));
}
// select (a | c), a, b -> select a, true, (select ~c, b, false)
if (match(CondVal, m_c_Or(m_Specific(TrueVal), m_Value(C))) &&
CondVal->hasOneUse() && isFreeToInvert(C, C->hasOneUse())) {
Value *NotC = Builder.CreateNot(C);
Value *AndV = Builder.CreateSelect(NotC, FalseVal, Zero);
return SelectInst::Create(TrueVal, One, AndV);
}
// select (c & ~b), a, b -> select b, true, (select c, a, false)
if (match(CondVal, m_c_And(m_Value(C), m_Not(m_Specific(FalseVal)))) &&
CondVal->hasOneUse()) {
Value *AndV = Builder.CreateSelect(C, TrueVal, Zero);
return SelectInst::Create(FalseVal, One, AndV);
}

if (match(FalseVal, m_Zero()) || match(TrueVal, m_One())) {
Use *Y = nullptr;
Expand Down
165 changes: 123 additions & 42 deletions llvm/test/Transforms/InstCombine/select-and-or.ll
View file
Original file line number Diff line number Diff line change
Expand Up @@ -604,9 +604,8 @@ define <2 x i1> @and_or1_op1not_vec(<2 x i1> %a, <2 x i1> %b) {

define i1 @or_and1(i1 %a, i1 %b, i1 %c) {
; CHECK-LABEL: @or_and1(
; CHECK-NEXT: [[NOTB:%.*]] = xor i1 [[B:%.*]], true
; CHECK-NEXT: [[COND:%.*]] = and i1 [[NOTB]], [[C:%.*]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[A:%.*]], i1 [[B]]
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i1 [[A:%.*]], i1 false
; CHECK-NEXT: [[R:%.*]] = select i1 [[B:%.*]], i1 true, i1 [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%notb = xor i1 %b, true
Expand All @@ -617,9 +616,8 @@ define i1 @or_and1(i1 %a, i1 %b, i1 %c) {

define i1 @or_and2(i1 %a, i1 %b, i1 %c) {
; CHECK-LABEL: @or_and2(
; CHECK-NEXT: [[NOTC:%.*]] = xor i1 [[C:%.*]], true
; CHECK-NEXT: [[COND:%.*]] = or i1 [[NOTC]], [[A:%.*]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[A]], i1 [[B:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i1 [[B:%.*]], i1 false
; CHECK-NEXT: [[R:%.*]] = select i1 [[A:%.*]], i1 true, i1 [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%notc = xor i1 %c, true
Expand All @@ -628,30 +626,24 @@ define i1 @or_and2(i1 %a, i1 %b, i1 %c) {
ret i1 %r
}

define i1 @or_and1_commuted(i1 %a, i1 %b) {
define i1 @or_and1_commuted(i1 %a, i1 %b, i1 %c) {
; CHECK-LABEL: @or_and1_commuted(
; CHECK-NEXT: [[C:%.*]] = call i1 @gen_i1()
; CHECK-NEXT: [[NOTB:%.*]] = xor i1 [[B:%.*]], true
; CHECK-NEXT: [[COND:%.*]] = and i1 [[C]], [[NOTB]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[A:%.*]], i1 [[B]]
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i1 [[A:%.*]], i1 false
; CHECK-NEXT: [[R:%.*]] = select i1 [[B:%.*]], i1 true, i1 [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%c = call i1 @gen_i1()
%notb = xor i1 %b, true
%cond = and i1 %c, %notb
%r = select i1 %cond, i1 %a, i1 %b
ret i1 %r
}

define i1 @or_and2_commuted(i1 %b, i1 %c) {
define i1 @or_and2_commuted(i1 %a, i1 %b, i1 %c) {
; CHECK-LABEL: @or_and2_commuted(
; CHECK-NEXT: [[A:%.*]] = call i1 @gen_i1()
; CHECK-NEXT: [[NOTC:%.*]] = xor i1 [[C:%.*]], true
; CHECK-NEXT: [[COND:%.*]] = or i1 [[A]], [[NOTC]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[A]], i1 [[B:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i1 [[B:%.*]], i1 false
; CHECK-NEXT: [[R:%.*]] = select i1 [[A:%.*]], i1 true, i1 [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%a = call i1 @gen_i1()
%notc = xor i1 %c, true
%cond = or i1 %a, %notc
%r = select i1 %cond, i1 %a, i1 %b
Expand Down Expand Up @@ -688,58 +680,58 @@ define i1 @or_and2_multiuse(i1 %a, i1 %b, i1 %c) {
ret i1 %r
}

define <2 x i1> @or_and1_vec(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
define <2 x i1> @or_and1_vec(<2 x i1> %a, <2 x i1> %b) {
; CHECK-LABEL: @or_and1_vec(
; CHECK-NEXT: [[NOTB:%.*]] = xor <2 x i1> [[B:%.*]], <i1 true, i1 true>
; CHECK-NEXT: [[COND:%.*]] = and <2 x i1> [[NOTB]], [[C:%.*]]
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[COND]], <2 x i1> [[A:%.*]], <2 x i1> [[B]]
; CHECK-NEXT: [[C:%.*]] = call <2 x i1> @gen_v2i1()
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[C]], <2 x i1> [[A:%.*]], <2 x i1> zeroinitializer
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[B:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%c = call <2 x i1> @gen_v2i1()
%notb = xor <2 x i1> %b, <i1 true, i1 true>
%cond = and <2 x i1> %notb, %c
%cond = and <2 x i1> %c, %notb
%r = select <2 x i1> %cond, <2 x i1> %a, <2 x i1> %b
ret <2 x i1> %r
}

define <2 x i1> @or_and2_vec(<2 x i1> %a, <2 x i1> %b, <2 x i1> %c) {
define <2 x i1> @or_and2_vec(<2 x i1> %a, <2 x i1> %b) {
; CHECK-LABEL: @or_and2_vec(
; CHECK-NEXT: [[NOTC:%.*]] = xor <2 x i1> [[C:%.*]], <i1 true, i1 true>
; CHECK-NEXT: [[COND:%.*]] = or <2 x i1> [[NOTC]], [[A:%.*]]
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[COND]], <2 x i1> [[A]], <2 x i1> [[B:%.*]]
; CHECK-NEXT: [[C:%.*]] = call <2 x i1> @gen_v2i1()
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[C]], <2 x i1> [[B:%.*]], <2 x i1> zeroinitializer
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[A:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%c = call <2 x i1> @gen_v2i1()
%notc = xor <2 x i1> %c, <i1 true, i1 true>
%cond = or <2 x i1> %notc, %a
%cond = or <2 x i1> %a, %notc
%r = select <2 x i1> %cond, <2 x i1> %a, <2 x i1> %b
ret <2 x i1> %r
}

define <2 x i1> @or_and1_vec_commuted(<2 x i1> %a, <2 x i1> %b) {
; CHECK-LABEL: @or_and1_vec_commuted(
; CHECK-NEXT: [[C:%.*]] = call <2 x i1> @gen_v2i1()
; CHECK-NEXT: [[NOTB:%.*]] = xor <2 x i1> [[B:%.*]], <i1 true, i1 true>
; CHECK-NEXT: [[COND:%.*]] = and <2 x i1> [[C]], [[NOTB]]
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[COND]], <2 x i1> [[A:%.*]], <2 x i1> [[B]]
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[C]], <2 x i1> [[A:%.*]], <2 x i1> zeroinitializer
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[B:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%c = call <2 x i1> @gen_v2i1()
%notb = xor <2 x i1> %b, <i1 true, i1 true>
%cond = and <2 x i1> %c, %notb
%cond = and <2 x i1> %notb, %c
%r = select <2 x i1> %cond, <2 x i1> %a, <2 x i1> %b
ret <2 x i1> %r
}

define <2 x i1> @or_and2_vec_commuted(<2 x i1> %b, <2 x i1> %c) {
define <2 x i1> @or_and2_vec_commuted(<2 x i1> %a, <2 x i1> %b) {
; CHECK-LABEL: @or_and2_vec_commuted(
; CHECK-NEXT: [[A:%.*]] = call <2 x i1> @gen_v2i1()
; CHECK-NEXT: [[NOTC:%.*]] = xor <2 x i1> [[C:%.*]], <i1 true, i1 true>
; CHECK-NEXT: [[COND:%.*]] = or <2 x i1> [[A]], [[NOTC]]
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[COND]], <2 x i1> [[A]], <2 x i1> [[B:%.*]]
; CHECK-NEXT: [[C:%.*]] = call <2 x i1> @gen_v2i1()
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[C]], <2 x i1> [[B:%.*]], <2 x i1> zeroinitializer
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[A:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%a = call <2 x i1> @gen_v2i1()
%c = call <2 x i1> @gen_v2i1()
%notc = xor <2 x i1> %c, <i1 true, i1 true>
%cond = or <2 x i1> %a, %notc
%cond = or <2 x i1> %notc, %a
%r = select <2 x i1> %cond, <2 x i1> %a, <2 x i1> %b
ret <2 x i1> %r
}
Expand Down Expand Up @@ -773,9 +765,7 @@ define i1 @or_and2_wrong_operand(i1 %a, i1 %b, i1 %c, i1 %d) {
define i1 @pr64558(i1 noundef %a, i1 noundef %b) {
; CHECK-LABEL: @pr64558(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[LNOT:%.*]] = xor i1 [[B:%.*]], true
; CHECK-NEXT: [[AND11:%.*]] = and i1 [[LNOT]], [[A:%.*]]
; CHECK-NEXT: [[COND_V:%.*]] = select i1 [[AND11]], i1 [[A]], i1 [[B]]
; CHECK-NEXT: [[COND_V:%.*]] = or i1 [[B:%.*]], [[A:%.*]]
; CHECK-NEXT: ret i1 [[COND_V]]
;
entry:
Expand All @@ -784,3 +774,94 @@ entry:
%cond.v = select i1 %and11, i1 %a, i1 %b
ret i1 %cond.v
}

define i1 @or_and3(i1 %a, i1 %b, i32 %x, i32 %y) {
; CHECK-LABEL: @or_and3(
; CHECK-NEXT: [[C:%.*]] = icmp ne i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C]], i1 [[B:%.*]], i1 false
; CHECK-NEXT: [[R:%.*]] = select i1 [[A:%.*]], i1 true, i1 [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%c = icmp eq i32 %x, %y
%cond = or i1 %a, %c
%r = select i1 %cond, i1 %a, i1 %b
ret i1 %r
}

define i1 @or_and3_commuted(i1 %a, i1 %b, i32 %x, i32 %y) {
; CHECK-LABEL: @or_and3_commuted(
; CHECK-NEXT: [[C:%.*]] = icmp ne i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C]], i1 [[B:%.*]], i1 false
; CHECK-NEXT: [[R:%.*]] = select i1 [[A:%.*]], i1 true, i1 [[TMP1]]
; CHECK-NEXT: ret i1 [[R]]
;
%c = icmp eq i32 %x, %y
%cond = or i1 %c, %a
%r = select i1 %cond, i1 %a, i1 %b
ret i1 %r
}

define i1 @or_and3_not_free_to_invert(i1 %a, i1 %b, i1 %c) {
; CHECK-LABEL: @or_and3_not_free_to_invert(
; CHECK-NEXT: [[COND:%.*]] = or i1 [[A:%.*]], [[C:%.*]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[A]], i1 [[B:%.*]]
; CHECK-NEXT: ret i1 [[R]]
;
%cond = or i1 %a, %c
%r = select i1 %cond, i1 %a, i1 %b
ret i1 %r
}

define i1 @or_and3_multiuse(i1 %a, i1 %b, i32 %x, i32 %y) {
; CHECK-LABEL: @or_and3_multiuse(
; CHECK-NEXT: [[C:%.*]] = icmp eq i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[COND:%.*]] = or i1 [[C]], [[A:%.*]]
; CHECK-NEXT: call void @use(i1 [[COND]])
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[A]], i1 [[B:%.*]]
; CHECK-NEXT: ret i1 [[R]]
;
%c = icmp eq i32 %x, %y
%cond = or i1 %a, %c
call void @use(i1 %cond)
%r = select i1 %cond, i1 %a, i1 %b
ret i1 %r
}

define <2 x i1> @or_and3_vec(<2 x i1> %a, <2 x i1> %b, <2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @or_and3_vec(
; CHECK-NEXT: [[C:%.*]] = icmp ne <2 x i32> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[C]], <2 x i1> [[B:%.*]], <2 x i1> zeroinitializer
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[A:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%c = icmp eq <2 x i32> %x, %y
%cond = or <2 x i1> %a, %c
%r = select <2 x i1> %cond, <2 x i1> %a, <2 x i1> %b
ret <2 x i1> %r
}

define <2 x i1> @or_and3_vec_commuted(<2 x i1> %a, <2 x i1> %b, <2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @or_and3_vec_commuted(
; CHECK-NEXT: [[C:%.*]] = icmp ne <2 x i32> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = select <2 x i1> [[C]], <2 x i1> [[B:%.*]], <2 x i1> zeroinitializer
; CHECK-NEXT: [[R:%.*]] = select <2 x i1> [[A:%.*]], <2 x i1> <i1 true, i1 true>, <2 x i1> [[TMP1]]
; CHECK-NEXT: ret <2 x i1> [[R]]
;
%c = icmp eq <2 x i32> %x, %y
%cond = or <2 x i1> %c, %a
%r = select <2 x i1> %cond, <2 x i1> %a, <2 x i1> %b
ret <2 x i1> %r
}

define i1 @or_and3_wrong_operand(i1 %a, i1 %b, i32 %x, i32 %y, i1 %d) {
; CHECK-LABEL: @or_and3_wrong_operand(
; CHECK-NEXT: [[C:%.*]] = icmp eq i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[COND:%.*]] = or i1 [[C]], [[A:%.*]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[COND]], i1 [[D:%.*]], i1 [[B:%.*]]
; CHECK-NEXT: ret i1 [[R]]
;
%c = icmp eq i32 %x, %y
%cond = or i1 %a, %c
%r = select i1 %cond, i1 %d, i1 %b
ret i1 %r
}

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