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[LVI][SCCP][CVP] Add basic ConstantFPRange support #111544

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[LVI][SCCP][CVP] Add basic ConstantFPRange support #111544

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398fa6e
[LVI][SCCP] Add basic ConstantFPRange support
dtcxzyw Oct 8, 2024
0436fcc
[CVP] Fix predicate mismatch
dtcxzyw Oct 9, 2024
d98dd0d
[ValueLattice] Address review comments.
dtcxzyw Oct 9, 2024
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29 changes: 15 additions & 14 deletions llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -233,21 +233,22 @@ static Value *getValueOnEdge(LazyValueInfo *LVI, Value *Incoming,
// value can never be that constant. In that case replace the incoming
// value with the other value of the select. This often allows us to
// remove the select later.
if (!SI->getType()->isFPOrFPVectorTy()) {
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Maybe better to make it an isIntOrIntVectorTy. Does this handle the pointer case below?

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It also handles the pointer case. See also Transforms/CorrelatedValuePropagation/basic.ll:


; "true" case for CorrelatedValuePropagation
define void @loop2(ptr %x, ptr %y) {
; CHECK-LABEL: define void @loop2
; CHECK-SAME: (ptr [[X:%.*]], ptr [[Y:%.*]]) {
; CHECK-NEXT:  entry:
; CHECK-NEXT:    br label [[LOOP:%.*]]
; CHECK:       loop:
; CHECK-NEXT:    [[PHI:%.*]] = phi ptr [ [[F:%.*]], [[LOOP]] ], [ [[X]], [[ENTRY:%.*]] ]
; CHECK-NEXT:    [[F]] = tail call ptr @f(ptr [[PHI]])
; CHECK-NEXT:    [[CMP1:%.*]] = icmp eq ptr [[F]], [[Y]]
; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[CMP1]], ptr null, ptr [[F]]
; CHECK-NEXT:    [[CMP2:%.*]] = icmp eq ptr [[SEL]], null
; CHECK-NEXT:    br i1 [[CMP2]], label [[RETURN:%.*]], label [[LOOP]]
; CHECK:       return:
; CHECK-NEXT:    ret void
;
entry:
  br label %loop

loop:
  %phi = phi ptr [ %sel, %loop ], [ %x, %entry ]
  %f = tail call ptr @f(ptr %phi)
  %cmp1 = icmp eq ptr %f, %y
  %sel = select i1 %cmp1, ptr null, ptr %f
  %cmp2 = icmp eq ptr %sel, null
  br i1 %cmp2, label %return, label %loop

return:
  ret void
}

// The "false" case
if (auto *C = dyn_cast<Constant>(SI->getFalseValue()))
if (auto *Res = dyn_cast_or_null<ConstantInt>(LVI->getPredicateOnEdge(
ICmpInst::ICMP_EQ, SI, C, From, To, CxtI));
Res && Res->isZero())
return SI->getTrueValue();

// The "false" case
if (auto *C = dyn_cast<Constant>(SI->getFalseValue()))
if (auto *Res = dyn_cast_or_null<ConstantInt>(
LVI->getPredicateOnEdge(ICmpInst::ICMP_EQ, SI, C, From, To, CxtI));
Res && Res->isZero())
return SI->getTrueValue();

// The "true" case,
// similar to the select "false" case, but try the select "true" value
if (auto *C = dyn_cast<Constant>(SI->getTrueValue()))
if (auto *Res = dyn_cast_or_null<ConstantInt>(
LVI->getPredicateOnEdge(ICmpInst::ICMP_EQ, SI, C, From, To, CxtI));
Res && Res->isZero())
return SI->getFalseValue();
// The "true" case,
// similar to the select "false" case, but try the select "true" value
if (auto *C = dyn_cast<Constant>(SI->getTrueValue()))
if (auto *Res = dyn_cast_or_null<ConstantInt>(LVI->getPredicateOnEdge(
ICmpInst::ICMP_EQ, SI, C, From, To, CxtI));
Res && Res->isZero())
return SI->getFalseValue();
}

return nullptr;
}
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