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Combine (fcmp cc0 x, y) | (fcmp cc1 x, y) into a single fcmp when possible.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57515 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-10-14 18:44:08 +00:00
parent 4990b257dd
commit 403006205f
2 changed files with 75 additions and 1 deletions
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42
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -3136,6 +3136,7 @@ static unsigned getFCmpCode(FCmpInst::Predicate CC, bool &isOrdered) {
case FCmpInst::FCMP_UNE: return 5; // 101
case FCmpInst::FCMP_OLE: isOrdered = true; return 6; // 110
case FCmpInst::FCMP_ULE: return 6; // 110
// True -> 7
default:
// Not expecting FCMP_FALSE and FCMP_TRUE;
assert(0 && "Unexpected FCmp predicate!");
@ -3219,6 +3220,7 @@ static Value *getFCmpValue(bool isordered, unsigned code,
return new FCmpInst(FCmpInst::FCMP_OLE, LHS, RHS);
else
return new FCmpInst(FCmpInst::FCMP_ULE, LHS, RHS);
case 7: return ConstantInt::getTrue();
}
}
@ -4555,7 +4557,7 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
if (FCmpInst *RHS = dyn_cast<FCmpInst>(I.getOperand(1))) {
if (LHS->getPredicate() == FCmpInst::FCMP_UNO &&
RHS->getPredicate() == FCmpInst::FCMP_UNO &&
LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType())
LHS->getOperand(0)->getType() == RHS->getOperand(0)->getType()) {
if (ConstantFP *LHSC = dyn_cast<ConstantFP>(LHS->getOperand(1)))
if (ConstantFP *RHSC = dyn_cast<ConstantFP>(RHS->getOperand(1))) {
// If either of the constants are nans, then the whole thing returns
@ -4568,6 +4570,44 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
return new FCmpInst(FCmpInst::FCMP_UNO, LHS->getOperand(0),
RHS->getOperand(0));
}
} else {
Value *Op0LHS, *Op0RHS, *Op1LHS, *Op1RHS;
FCmpInst::Predicate Op0CC, Op1CC;
if (match(Op0, m_FCmp(Op0CC, m_Value(Op0LHS), m_Value(Op0RHS))) &&
match(Op1, m_FCmp(Op1CC, m_Value(Op1LHS), m_Value(Op1RHS)))) {
if (Op0LHS == Op1RHS && Op0RHS == Op1LHS) {
// Swap RHS operands to match LHS.
Op1CC = FCmpInst::getSwappedPredicate(Op1CC);
std::swap(Op1LHS, Op1RHS);
}
if (Op0LHS == Op1LHS && Op0RHS == Op1RHS) {
// Simplify (fcmp cc0 x, y) | (fcmp cc1 x, y).
if (Op0CC == Op1CC)
return new FCmpInst((FCmpInst::Predicate)Op0CC, Op0LHS, Op0RHS);
else if (Op0CC == FCmpInst::FCMP_TRUE ||
Op1CC == FCmpInst::FCMP_TRUE)
return ReplaceInstUsesWith(I, ConstantInt::getTrue());
else if (Op0CC == FCmpInst::FCMP_FALSE)
return ReplaceInstUsesWith(I, Op1);
else if (Op1CC == FCmpInst::FCMP_FALSE)
return ReplaceInstUsesWith(I, Op0);
bool Op0Ordered;
bool Op1Ordered;
unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
if (Op0Ordered == Op1Ordered) {
// If both are ordered or unordered, return a new fcmp with
// or'ed predicates.
Value *RV = getFCmpValue(Op0Ordered, Op0Pred|Op1Pred,
Op0LHS, Op0RHS);
if (Instruction *I = dyn_cast<Instruction>(RV))
return I;
// Otherwise, it's a constant boolean value...
return ReplaceInstUsesWith(I, RV);
}
}
}
}
}
}

34
test/Transforms/InstCombine/or-fcmp.ll Normal file
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@ -0,0 +1,34 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep fcmp | count 3
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep ret | grep 1
define zeroext i8 @t1(float %x, float %y) nounwind {
%a = fcmp ueq float %x, %y ; <i1> [#uses=1]
%b = fcmp uno float %x, %y ; <i1> [#uses=1]
%c = or i1 %a, %b
%retval = zext i1 %c to i8
ret i8 %retval
}
define zeroext i8 @t2(float %x, float %y) nounwind {
%a = fcmp olt float %x, %y ; <i1> [#uses=1]
%b = fcmp oeq float %x, %y ; <i1> [#uses=1]
%c = or i1 %a, %b
%retval = zext i1 %c to i8
ret i8 %retval
}
define zeroext i8 @t3(float %x, float %y) nounwind {
%a = fcmp ult float %x, %y ; <i1> [#uses=1]
%b = fcmp uge float %x, %y ; <i1> [#uses=1]
%c = or i1 %a, %b
%retval = zext i1 %c to i8
ret i8 %retval
}
define zeroext i8 @t4(float %x, float %y) nounwind {
%a = fcmp ult float %x, %y ; <i1> [#uses=1]
%b = fcmp ugt float %x, %y ; <i1> [#uses=1]
%c = or i1 %a, %b
%retval = zext i1 %c to i8
ret i8 %retval
}