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[ValueTracking] enhance matching of smin/smax with 'not' operands 

The cmyk tests are based on the known regression that resulted from:
rGf2fbdf76d8d0

So this improvement in analysis might be enough to restore that commit.
This commit is contained in:
Sanjay Patel 2020-04-05 08:51:29 -04:00
parent 59d10dc703
commit 867f0c3c4d
3 changed files with 62 additions and 65 deletions
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39
llvm/lib/Analysis/ValueTracking.cpp
View File

@ -5124,6 +5124,21 @@ static SelectPatternResult matchMinMaxOfMinMax(CmpInst::Predicate Pred,
return {SPF_UNKNOWN, SPNB_NA, false}; return {SPF_UNKNOWN, SPNB_NA, false};
} }
/// If the input value is the result of a 'not' op, constant integer, or vector
/// splat of a constant integer, return the bitwise-not source value.
/// TODO: This could be extended to handle non-splat vector integer constants.
static Value *getNotValue(Value *V) {
Value *NotV;
if (match(V, m_Not(m_Value(NotV))))
return NotV;
const APInt *C;
if (match(V, m_APInt(C)))
return ConstantInt::get(V->getType(), ~(*C));
return nullptr;
}
/// Match non-obvious integer minimum and maximum sequences. /// Match non-obvious integer minimum and maximum sequences.
static SelectPatternResult matchMinMax(CmpInst::Predicate Pred, static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
Value *CmpLHS, Value *CmpRHS, Value *CmpLHS, Value *CmpRHS,
@ -5159,6 +5174,17 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
match(TrueVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS)))) match(TrueVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS))))
return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false}; return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false};
// Look through 'not' ops to find disguised signed min/max.
// (X >s Y) ? ~X : ~Y ==> (~X <s ~Y) ? ~X : ~Y ==> SMIN(~X, ~Y)
// (X <s Y) ? ~X : ~Y ==> (~X >s ~Y) ? ~X : ~Y ==> SMAX(~X, ~Y)
if (CmpLHS == getNotValue(TrueVal) && CmpRHS == getNotValue(FalseVal))
return {Pred == CmpInst::ICMP_SGT ? SPF_SMIN : SPF_SMAX, SPNB_NA, false};
// (X >s Y) ? ~Y : ~X ==> (~X <s ~Y) ? ~Y : ~X ==> SMAX(~Y, ~X)
// (X <s Y) ? ~Y : ~X ==> (~X >s ~Y) ? ~Y : ~X ==> SMIN(~Y, ~X)
if (CmpLHS == getNotValue(FalseVal) && CmpRHS == getNotValue(TrueVal))
return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false};
const APInt *C1; const APInt *C1;
if (!match(CmpRHS, m_APInt(C1))) if (!match(CmpRHS, m_APInt(C1)))
return {SPF_UNKNOWN, SPNB_NA, false}; return {SPF_UNKNOWN, SPNB_NA, false};
@ -5182,19 +5208,6 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
return {CmpLHS == FalseVal ? SPF_UMAX : SPF_UMIN, SPNB_NA, false}; return {CmpLHS == FalseVal ? SPF_UMAX : SPF_UMIN, SPNB_NA, false};
} }
// Look through 'not' ops to find disguised signed min/max.
// (X >s C) ? ~X : ~C ==> (~X <s ~C) ? ~X : ~C ==> SMIN(~X, ~C)
// (X <s C) ? ~X : ~C ==> (~X >s ~C) ? ~X : ~C ==> SMAX(~X, ~C)
if (match(TrueVal, m_Not(m_Specific(CmpLHS))) &&
match(FalseVal, m_APInt(C2)) && ~(*C1) == *C2)
return {Pred == CmpInst::ICMP_SGT ? SPF_SMIN : SPF_SMAX, SPNB_NA, false};
// (X >s C) ? ~C : ~X ==> (~X <s ~C) ? ~C : ~X ==> SMAX(~C, ~X)
// (X <s C) ? ~C : ~X ==> (~X >s ~C) ? ~C : ~X ==> SMIN(~C, ~X)
if (match(FalseVal, m_Not(m_Specific(CmpLHS))) &&
match(TrueVal, m_APInt(C2)) && ~(*C1) == *C2)
return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false};
return {SPF_UNKNOWN, SPNB_NA, false}; return {SPF_UNKNOWN, SPNB_NA, false};
} }

80
llvm/test/Transforms/InstCombine/max-of-nots.ll
View File

@ -391,18 +391,14 @@ define void @cmyk(i8 %r, i8 %g, i8 %b) {
define void @cmyk2(i8 %r, i8 %g, i8 %b) { define void @cmyk2(i8 %r, i8 %g, i8 %b) {
; CHECK-LABEL: @cmyk2( ; CHECK-LABEL: @cmyk2(
; CHECK-NEXT: [[NOTR:%.*]] = xor i8 [[R:%.*]], -1 ; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i8 [[R:%.*]], [[B:%.*]]
; CHECK-NEXT: [[NOTG:%.*]] = xor i8 [[G:%.*]], -1 ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i8 [[R]], i8 [[B]]
; CHECK-NEXT: [[NOTB:%.*]] = xor i8 [[B:%.*]], -1 ; CHECK-NEXT: [[TMP3:%.*]] = icmp sgt i8 [[TMP2]], [[G:%.*]]
; CHECK-NEXT: [[CMP_GR:%.*]] = icmp slt i8 [[G]], [[R]] ; CHECK-NEXT: [[K_V:%.*]] = select i1 [[TMP3]], i8 [[TMP2]], i8 [[G]]
; CHECK-NEXT: [[CMP_BR:%.*]] = icmp slt i8 [[B]], [[R]] ; CHECK-NEXT: [[K:%.*]] = xor i8 [[K_V]], -1
; CHECK-NEXT: [[MIN_BR:%.*]] = select i1 [[CMP_BR]], i8 [[NOTR]], i8 [[NOTB]] ; CHECK-NEXT: [[CK:%.*]] = sub i8 [[K_V]], [[R]]
; CHECK-NEXT: [[CMP_BG:%.*]] = icmp slt i8 [[B]], [[G]] ; CHECK-NEXT: [[MK:%.*]] = sub i8 [[K_V]], [[G]]
; CHECK-NEXT: [[MIN_BG:%.*]] = select i1 [[CMP_BG]], i8 [[NOTG]], i8 [[NOTB]] ; CHECK-NEXT: [[YK:%.*]] = sub i8 [[K_V]], [[B]]
; CHECK-NEXT: [[K:%.*]] = select i1 [[CMP_GR]], i8 [[MIN_BR]], i8 [[MIN_BG]]
; CHECK-NEXT: [[CK:%.*]] = sub i8 [[NOTR]], [[K]]
; CHECK-NEXT: [[MK:%.*]] = sub i8 [[NOTG]], [[K]]
; CHECK-NEXT: [[YK:%.*]] = sub i8 [[NOTB]], [[K]]
; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]]) ; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]])
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
@ -424,18 +420,14 @@ define void @cmyk2(i8 %r, i8 %g, i8 %b) {
define void @cmyk3(i8 %r, i8 %g, i8 %b) { define void @cmyk3(i8 %r, i8 %g, i8 %b) {
; CHECK-LABEL: @cmyk3( ; CHECK-LABEL: @cmyk3(
; CHECK-NEXT: [[NOTR:%.*]] = xor i8 [[R:%.*]], -1 ; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i8 [[R:%.*]], [[B:%.*]]
; CHECK-NEXT: [[NOTG:%.*]] = xor i8 [[G:%.*]], -1 ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i8 [[R]], i8 [[B]]
; CHECK-NEXT: [[NOTB:%.*]] = xor i8 [[B:%.*]], -1 ; CHECK-NEXT: [[TMP3:%.*]] = icmp sgt i8 [[TMP2]], [[G:%.*]]
; CHECK-NEXT: [[CMP_GR:%.*]] = icmp slt i8 [[G]], [[R]] ; CHECK-NEXT: [[K_V:%.*]] = select i1 [[TMP3]], i8 [[TMP2]], i8 [[G]]
; CHECK-NEXT: [[CMP_BR:%.*]] = icmp sgt i8 [[R]], [[B]] ; CHECK-NEXT: [[K:%.*]] = xor i8 [[K_V]], -1
; CHECK-NEXT: [[MIN_BR:%.*]] = select i1 [[CMP_BR]], i8 [[NOTR]], i8 [[NOTB]] ; CHECK-NEXT: [[CK:%.*]] = sub i8 [[K_V]], [[R]]
; CHECK-NEXT: [[CMP_BG:%.*]] = icmp slt i8 [[B]], [[G]] ; CHECK-NEXT: [[MK:%.*]] = sub i8 [[K_V]], [[G]]
; CHECK-NEXT: [[MIN_BG:%.*]] = select i1 [[CMP_BG]], i8 [[NOTG]], i8 [[NOTB]] ; CHECK-NEXT: [[YK:%.*]] = sub i8 [[K_V]], [[B]]
; CHECK-NEXT: [[K:%.*]] = select i1 [[CMP_GR]], i8 [[MIN_BR]], i8 [[MIN_BG]]
; CHECK-NEXT: [[CK:%.*]] = sub i8 [[NOTR]], [[K]]
; CHECK-NEXT: [[MK:%.*]] = sub i8 [[NOTG]], [[K]]
; CHECK-NEXT: [[YK:%.*]] = sub i8 [[NOTB]], [[K]]
; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]]) ; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]])
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
@ -457,18 +449,14 @@ define void @cmyk3(i8 %r, i8 %g, i8 %b) {
define void @cmyk4(i8 %r, i8 %g, i8 %b) { define void @cmyk4(i8 %r, i8 %g, i8 %b) {
; CHECK-LABEL: @cmyk4( ; CHECK-LABEL: @cmyk4(
; CHECK-NEXT: [[NOTR:%.*]] = xor i8 [[R:%.*]], -1 ; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i8 [[R:%.*]], [[B:%.*]]
; CHECK-NEXT: [[NOTG:%.*]] = xor i8 [[G:%.*]], -1 ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i8 [[R]], i8 [[B]]
; CHECK-NEXT: [[NOTB:%.*]] = xor i8 [[B:%.*]], -1 ; CHECK-NEXT: [[TMP3:%.*]] = icmp sgt i8 [[TMP2]], [[G:%.*]]
; CHECK-NEXT: [[CMP_GR:%.*]] = icmp slt i8 [[G]], [[R]] ; CHECK-NEXT: [[K_V:%.*]] = select i1 [[TMP3]], i8 [[TMP2]], i8 [[G]]
; CHECK-NEXT: [[CMP_BR:%.*]] = icmp sgt i8 [[R]], [[B]] ; CHECK-NEXT: [[K:%.*]] = xor i8 [[K_V]], -1
; CHECK-NEXT: [[MIN_BR:%.*]] = select i1 [[CMP_BR]], i8 [[NOTR]], i8 [[NOTB]] ; CHECK-NEXT: [[CK:%.*]] = sub i8 [[K_V]], [[R]]
; CHECK-NEXT: [[CMP_BG:%.*]] = icmp sgt i8 [[G]], [[B]] ; CHECK-NEXT: [[MK:%.*]] = sub i8 [[K_V]], [[G]]
; CHECK-NEXT: [[MIN_BG:%.*]] = select i1 [[CMP_BG]], i8 [[NOTG]], i8 [[NOTB]] ; CHECK-NEXT: [[YK:%.*]] = sub i8 [[K_V]], [[B]]
; CHECK-NEXT: [[K:%.*]] = select i1 [[CMP_GR]], i8 [[MIN_BR]], i8 [[MIN_BG]]
; CHECK-NEXT: [[CK:%.*]] = sub i8 [[NOTR]], [[K]]
; CHECK-NEXT: [[MK:%.*]] = sub i8 [[NOTG]], [[K]]
; CHECK-NEXT: [[YK:%.*]] = sub i8 [[NOTB]], [[K]]
; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]]) ; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]])
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;
@ -490,18 +478,14 @@ define void @cmyk4(i8 %r, i8 %g, i8 %b) {
define void @cmyk5(i8 %r, i8 %g, i8 %b) { define void @cmyk5(i8 %r, i8 %g, i8 %b) {
; CHECK-LABEL: @cmyk5( ; CHECK-LABEL: @cmyk5(
; CHECK-NEXT: [[NOTR:%.*]] = xor i8 [[R:%.*]], -1 ; CHECK-NEXT: [[TMP1:%.*]] = icmp sgt i8 [[R:%.*]], [[B:%.*]]
; CHECK-NEXT: [[NOTG:%.*]] = xor i8 [[G:%.*]], -1 ; CHECK-NEXT: [[TMP2:%.*]] = select i1 [[TMP1]], i8 [[R]], i8 [[B]]
; CHECK-NEXT: [[NOTB:%.*]] = xor i8 [[B:%.*]], -1 ; CHECK-NEXT: [[TMP3:%.*]] = icmp sgt i8 [[TMP2]], [[G:%.*]]
; CHECK-NEXT: [[CMP_GR:%.*]] = icmp sgt i8 [[R]], [[G]] ; CHECK-NEXT: [[K_V:%.*]] = select i1 [[TMP3]], i8 [[TMP2]], i8 [[G]]
; CHECK-NEXT: [[CMP_BR:%.*]] = icmp sgt i8 [[R]], [[B]] ; CHECK-NEXT: [[K:%.*]] = xor i8 [[K_V]], -1
; CHECK-NEXT: [[MIN_BR:%.*]] = select i1 [[CMP_BR]], i8 [[NOTR]], i8 [[NOTB]] ; CHECK-NEXT: [[CK:%.*]] = sub i8 [[K_V]], [[R]]
; CHECK-NEXT: [[CMP_BG:%.*]] = icmp sgt i8 [[G]], [[B]] ; CHECK-NEXT: [[MK:%.*]] = sub i8 [[K_V]], [[G]]
; CHECK-NEXT: [[MIN_BG:%.*]] = select i1 [[CMP_BG]], i8 [[NOTG]], i8 [[NOTB]] ; CHECK-NEXT: [[YK:%.*]] = sub i8 [[K_V]], [[B]]
; CHECK-NEXT: [[K:%.*]] = select i1 [[CMP_GR]], i8 [[MIN_BR]], i8 [[MIN_BG]]
; CHECK-NEXT: [[CK:%.*]] = sub i8 [[NOTR]], [[K]]
; CHECK-NEXT: [[MK:%.*]] = sub i8 [[NOTG]], [[K]]
; CHECK-NEXT: [[YK:%.*]] = sub i8 [[NOTB]], [[K]]
; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]]) ; CHECK-NEXT: call void @use(i8 [[CK]], i8 [[MK]], i8 [[YK]], i8 [[K]])
; CHECK-NEXT: ret void ; CHECK-NEXT: ret void
; ;

8
llvm/unittests/Analysis/ValueTrackingTest.cpp
View File

@ -471,7 +471,7 @@ TEST_F(MatchSelectPatternTest, NotNotSMin) {
" %A = select i1 %cmp, i8 %an, i8 %bn\n" " %A = select i1 %cmp, i8 %an, i8 %bn\n"
" ret i8 %A\n" " ret i8 %A\n"
"}\n"); "}\n");
expectPattern({SPF_UNKNOWN, SPNB_NA, false}); expectPattern({SPF_SMIN, SPNB_NA, false});
} }
TEST_F(MatchSelectPatternTest, NotNotSMinSwap) { TEST_F(MatchSelectPatternTest, NotNotSMinSwap) {
@ -483,7 +483,7 @@ TEST_F(MatchSelectPatternTest, NotNotSMinSwap) {
" %A = select i1 %cmp, i8 %bn, i8 %an\n" " %A = select i1 %cmp, i8 %bn, i8 %an\n"
" ret i8 %A\n" " ret i8 %A\n"
"}\n"); "}\n");
expectPattern({SPF_UNKNOWN, SPNB_NA, false}); expectPattern({SPF_SMIN, SPNB_NA, false});
} }
TEST_F(MatchSelectPatternTest, NotNotSMax) { TEST_F(MatchSelectPatternTest, NotNotSMax) {
@ -495,7 +495,7 @@ TEST_F(MatchSelectPatternTest, NotNotSMax) {
" %A = select i1 %cmp, i8 %an, i8 %bn\n" " %A = select i1 %cmp, i8 %an, i8 %bn\n"
" ret i8 %A\n" " ret i8 %A\n"
"}\n"); "}\n");
expectPattern({SPF_UNKNOWN, SPNB_NA, false}); expectPattern({SPF_SMAX, SPNB_NA, false});
} }
TEST_F(MatchSelectPatternTest, NotNotSMaxSwap) { TEST_F(MatchSelectPatternTest, NotNotSMaxSwap) {
@ -507,7 +507,7 @@ TEST_F(MatchSelectPatternTest, NotNotSMaxSwap) {
" %A = select i1 %cmp, i8 %bn, i8 %an\n" " %A = select i1 %cmp, i8 %bn, i8 %an\n"
" ret i8 %A\n" " ret i8 %A\n"
"}\n"); "}\n");
expectPattern({SPF_UNKNOWN, SPNB_NA, false}); expectPattern({SPF_SMAX, SPNB_NA, false});
} }
TEST(ValueTracking, GuaranteedToTransferExecutionToSuccessor) { TEST(ValueTracking, GuaranteedToTransferExecutionToSuccessor) {