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[ValueTracking] Improve isImpliedCondition for conditions with matching operands.
This patch improves SimplifyCFG to catch cases like:
if (a < b) {
if (a > b) <- known to be false
unreachable;
}
Phabricator Revision: http://reviews.llvm.org/D18905
llvm-svn: 266767
This commit is contained in:
Chad Rosier
parent
27f8f7a332
commit
6c28047766
@ -436,16 +436,18 @@ template <typename T> class ArrayRef;
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/// E.g. if RangeMD is !{i32 0, i32 10, i32 15, i32 20} then return [0, 20).
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ConstantRange getConstantRangeFromMetadata(MDNode &RangeMD);
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/// Return true if RHS is known to be implied by LHS. A & B must be i1
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/// (boolean) values or a vector of such values. Note that the truth table for
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/// implication is the same as <=u on i1 values (but not <=s!). The truth
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/// table for both is:
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/// Return true if RHS is known to be implied by LHS. The implication may be
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/// either true or false depending on what is returned in ImpliedTrue.
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/// A & B must be i1 (boolean) values or a vector of such values. Note that
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/// the truth table for implication is the same as <=u on i1 values (but not
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/// <=s!). The truth table for both is:
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/// | T | F (B)
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/// T | T | F
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/// F | T | T
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/// (A)
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bool isImpliedCondition(Value *LHS, Value *RHS, const DataLayout &DL,
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unsigned Depth = 0, AssumptionCache *AC = nullptr,
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bool isImpliedCondition(Value *LHS, Value *RHS, bool &ImpliedTrue,
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const DataLayout &DL, unsigned Depth = 0,
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AssumptionCache *AC = nullptr,
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const Instruction *CxtI = nullptr,
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const DominatorTree *DT = nullptr);
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} // end namespace llvm
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@ -2131,14 +2131,16 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
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if (match(RHS, m_Zero()))
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return LHS;
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break;
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case ICmpInst::ICMP_UGE:
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case ICmpInst::ICMP_UGE: {
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// X >=u 1 -> X
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if (match(RHS, m_One()))
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return LHS;
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if (isImpliedCondition(RHS, LHS, Q.DL))
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bool ImpliedTrue;
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if (isImpliedCondition(RHS, LHS, ImpliedTrue, Q.DL) && ImpliedTrue)
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return getTrue(ITy);
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break;
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case ICmpInst::ICMP_SGE:
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}
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case ICmpInst::ICMP_SGE: {
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/// For signed comparison, the values for an i1 are 0 and -1
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/// respectively. This maps into a truth table of:
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/// LHS | RHS | LHS >=s RHS | LHS implies RHS
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@ -2146,9 +2148,11 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
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/// 0 | 1 | 1 (0 >= -1) | 1
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/// 1 | 0 | 0 (-1 >= 0) | 0
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/// 1 | 1 | 1 (-1 >= -1) | 1
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if (isImpliedCondition(LHS, RHS, Q.DL))
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bool ImpliedTrue;
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if (isImpliedCondition(LHS, RHS, ImpliedTrue, Q.DL) && ImpliedTrue)
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return getTrue(ITy);
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break;
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}
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case ICmpInst::ICMP_SLT:
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// X <s 0 -> X
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if (match(RHS, m_Zero()))
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@ -2159,11 +2163,13 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
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if (match(RHS, m_One()))
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return LHS;
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break;
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case ICmpInst::ICMP_ULE:
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if (isImpliedCondition(LHS, RHS, Q.DL))
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case ICmpInst::ICMP_ULE: {
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bool ImpliedTrue;
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if (isImpliedCondition(LHS, RHS, ImpliedTrue, Q.DL) && ImpliedTrue)
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return getTrue(ITy);
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break;
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}
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}
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}
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// If we are comparing with zero then try hard since this is a common case.
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@ -3788,16 +3788,104 @@ static bool isImpliedCondOperands(CmpInst::Predicate Pred, Value *ALHS,
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}
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}
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bool llvm::isImpliedCondition(Value *LHS, Value *RHS, const DataLayout &DL,
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unsigned Depth, AssumptionCache *AC,
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const Instruction *CxtI,
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/// Return true if "icmp2 BPred BLHS BRHS" is known to be implied by "icmp1
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/// APred ALHS ARHS". The implication may be either true or false depending on
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/// the return value of ImpliedTrue.
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static bool isImpliedCondMatchingOperands(CmpInst::Predicate APred, Value *ALHS,
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Value *ARHS, CmpInst::Predicate BPred,
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Value *BLHS, Value *BRHS,
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bool &ImpliedTrue) {
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// The operands of the two compares must match.
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bool IsMatchingOps = (ALHS == BLHS && ARHS == BRHS);
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bool IsSwappedOps = (ALHS == BRHS && ARHS == BLHS);
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if (!IsMatchingOps && !IsSwappedOps)
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return false;
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// Canonicalize the operands so they're matching.
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if (IsSwappedOps) {
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std::swap(BLHS, BRHS);
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BPred = ICmpInst::getSwappedPredicate(BPred);
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}
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// If the predicates match, then we know the first condition implies the
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// second is true.
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if (APred == BPred) {
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ImpliedTrue = true;
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return true;
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}
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// If an inverted APred matches BPred, we can infer the second condition is
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// false.
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if (CmpInst::getInversePredicate(APred) == BPred) {
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ImpliedTrue = false;
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return true;
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}
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// If a swapped APred matches BPred, we can infer the second condition is
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// false in many cases.
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if (CmpInst::getSwappedPredicate(APred) == BPred) {
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switch (APred) {
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default:
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break;
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case CmpInst::ICMP_UGT: // A >u B implies A <u B is false.
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case CmpInst::ICMP_ULT: // A <u B implies A >u B is false.
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case CmpInst::ICMP_SGT: // A >s B implies A <s B is false.
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case CmpInst::ICMP_SLT: // A <s B implies A >s B is false.
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ImpliedTrue = false;
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return true;
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}
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}
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// The predicates must match sign or at least one of them must be an equality
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// comparison (which is signless).
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if (ICmpInst::isSigned(APred) != ICmpInst::isSigned(BPred) &&
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!ICmpInst::isEquality(APred) && !ICmpInst::isEquality(BPred))
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return false;
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switch (APred) {
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default:
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break;
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case CmpInst::ICMP_EQ:
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// A == B implies A > B and A < B are false.
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if (CmpInst::isFalseWhenEqual(BPred)) {
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ImpliedTrue = false;
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return true;
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}
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break;
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case CmpInst::ICMP_UGT:
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case CmpInst::ICMP_ULT:
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case CmpInst::ICMP_SGT:
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case CmpInst::ICMP_SLT:
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// A > B implies A == B is false.
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// A < B implies A == B is false.
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if (BPred == CmpInst::ICMP_EQ) {
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ImpliedTrue = false;
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return true;
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}
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// A > B implies A != B is true.
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// A < B implies A != B is true.
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if (BPred == CmpInst::ICMP_NE) {
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ImpliedTrue = true;
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return true;
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}
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break;
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}
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return false;
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}
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bool llvm::isImpliedCondition(Value *LHS, Value *RHS, bool &ImpliedTrue,
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const DataLayout &DL, unsigned Depth,
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AssumptionCache *AC, const Instruction *CxtI,
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const DominatorTree *DT) {
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assert(LHS->getType() == RHS->getType() && "mismatched type");
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Type *OpTy = LHS->getType();
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assert(OpTy->getScalarType()->isIntegerTy(1));
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// LHS ==> RHS by definition
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if (LHS == RHS) return true;
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if (LHS == RHS) {
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ImpliedTrue = true;
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return true;
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}
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if (OpTy->isVectorTy())
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// TODO: extending the code below to handle vectors
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@ -3812,9 +3900,15 @@ bool llvm::isImpliedCondition(Value *LHS, Value *RHS, const DataLayout &DL,
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!match(RHS, m_ICmp(BPred, m_Value(BLHS), m_Value(BRHS))))
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return false;
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if (APred == BPred)
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if (isImpliedCondMatchingOperands(APred, ALHS, ARHS, BPred, BLHS, BRHS,
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ImpliedTrue))
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return true;
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if (APred == BPred) {
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ImpliedTrue = true;
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return isImpliedCondOperands(APred, ALHS, ARHS, BLHS, BRHS, DL, Depth, AC,
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CxtI, DT);
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}
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return false;
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}
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@ -928,9 +928,10 @@ bool JumpThreading::ProcessImpliedCondition(BasicBlock *BB) {
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if (!PBI || !PBI->isConditional() || PBI->getSuccessor(0) != CurrentBB)
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return false;
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if (isImpliedCondition(PBI->getCondition(), Cond, DL)) {
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BI->getSuccessor(1)->removePredecessor(BB);
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BranchInst::Create(BI->getSuccessor(0), BI);
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bool ImpliedTrue;
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if (isImpliedCondition(PBI->getCondition(), Cond, ImpliedTrue, DL)) {
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BI->getSuccessor(ImpliedTrue ? 1 : 0)->removePredecessor(BB);
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BranchInst::Create(BI->getSuccessor(ImpliedTrue ? 0 : 1), BI);
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BI->eraseFromParent();
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return true;
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}
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@ -2722,13 +2722,17 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
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// If BI is reached from the true path of PBI and PBI's condition implies
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// BI's condition, we know the direction of the BI branch.
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bool ImpliedTrue;
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if (PBI->getSuccessor(0) == BI->getParent() &&
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isImpliedCondition(PBI->getCondition(), BI->getCondition(), DL) &&
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isImpliedCondition(PBI->getCondition(), BI->getCondition(), ImpliedTrue,
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DL) &&
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PBI->getSuccessor(0) != PBI->getSuccessor(1) &&
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BB->getSinglePredecessor()) {
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// Turn this into a branch on constant.
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auto *OldCond = BI->getCondition();
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BI->setCondition(ConstantInt::getTrue(BB->getContext()));
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ConstantInt *CI = ImpliedTrue ? ConstantInt::getTrue(BB->getContext())
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: ConstantInt::getFalse(BB->getContext());
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BI->setCondition(CI);
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RecursivelyDeleteTriviallyDeadInstructions(OldCond);
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return true; // Nuke the branch on constant.
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}
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@ -96,3 +96,32 @@ define void @test2(i32 %i, i32 %len, i1* %c.ptr) {
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call void @side_effect(i32 %t)
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ret void
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}
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; A s<= B implies A s> B is false.
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; CHECK-LABEL: @test3(
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; CHECK: entry:
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; CHECK: br i1 %cmp, label %if.end, label %if.end3
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; CHECK-NOT: br i1 %cmp1, label %if.then2, label %if.end
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; CHECK-NOT: call void @side_effect(i32 0)
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; CHECK: br label %if.end3
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; CHECK: ret void
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define void @test3(i32 %a, i32 %b) {
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entry:
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%cmp = icmp sle i32 %a, %b
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br i1 %cmp, label %if.then, label %if.end3
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if.then:
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%cmp1 = icmp sgt i32 %a, %b
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br i1 %cmp1, label %if.then2, label %if.end
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if.then2:
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call void @side_effect(i32 0)
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br label %if.end
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if.end:
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br label %if.end3
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if.end3:
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ret void
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}
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478
test/Transforms/SimplifyCFG/implied-cond-matching.ll
Normal file
478
test/Transforms/SimplifyCFG/implied-cond-matching.ll
Normal file
@ -0,0 +1,478 @@
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; RUN: opt %s -S -simplifycfg | FileCheck %s
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; Test same condition with swapped operands.
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; void test_swapped_ops(unsigned a, unsigned b) {
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; if (a > b) {
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; if (b > a) <- always false
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; dead();
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; alive();
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; }
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; }
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;
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; CHECK-LABEL: @test_swapped_ops
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; CHECK-NOT: call void @dead()
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; CHECK: call void @alive()
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; CHECK: ret
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define void @test_swapped_ops(i32 %a, i32 %b) {
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entry:
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%cmp = icmp ugt i32 %a, %b
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br i1 %cmp, label %if.then, label %if.end3
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if.then:
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%cmp1 = icmp ugt i32 %b, %a
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br i1 %cmp1, label %if.then2, label %if.end
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if.then2:
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call void @dead()
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br label %if.end
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if.end:
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call void @alive()
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br label %if.end3
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if.end3:
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ret void
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}
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; void test_swapped_pred(unsigned a, unsigned b) {
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; if (a > b) {
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; alive();
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; if (b < a) <- always true; remove branch
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; alive();
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; }
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; }
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;
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; CHECK-LABEL: @test_swapped_pred
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; CHECK: call void @alive()
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; CHECK-NEXT: call void @alive()
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; CHECK: ret
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define void @test_swapped_pred(i32 %a, i32 %b) {
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entry:
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%cmp = icmp ugt i32 %a, %b
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br i1 %cmp, label %if.then, label %if.end3
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if.then:
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call void @alive()
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%cmp1 = icmp ult i32 %b, %a
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br i1 %cmp1, label %if.then2, label %if.end3
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if.then2:
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call void @alive()
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br label %if.end3
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if.end3:
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ret void
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}
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; A == B implies A >u B is false
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; A == B implies A <u B is false
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; CHECK-LABEL: @test_eq_unsigned
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; CHECK-NOT: dead
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; CHECK: ret void
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define void @test_eq_unsigned(i32 %a, i32 %b) {
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entry:
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%cmp = icmp eq i32 %a, %b
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br i1 %cmp, label %if.end, label %if.end9
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if.end:
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%cmp3 = icmp ugt i32 %a, %b
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br i1 %cmp3, label %if.then4, label %if.end5
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if.then4:
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call void @dead()
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br label %if.end5
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if.end5:
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%cmp6 = icmp ult i32 %a, %b
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br i1 %cmp6, label %if.then7, label %if.end8
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if.then7:
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call void @dead()
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br label %if.end8
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if.end8:
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br label %if.end9
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if.end9:
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ret void
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}
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; A == B implies A >s B is false
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; A == B implies A <s B is false
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; CHECK-LABEL: @test_eq_signed
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; CHECK-NOT: dead
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; CHECK: ret void
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define void @test_eq_signed(i32 %a, i32 %b) {
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entry:
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%cmp = icmp eq i32 %a, %b
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br i1 %cmp, label %if.end, label %if.end9
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if.end:
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%cmp3 = icmp sgt i32 %a, %b
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br i1 %cmp3, label %if.then4, label %if.end5
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if.then4:
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call void @dead()
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br label %if.end5
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if.end5:
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%cmp6 = icmp slt i32 %a, %b
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br i1 %cmp6, label %if.then7, label %if.end8
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if.then7:
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call void @dead()
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br label %if.end8
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if.end8:
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br label %if.end9
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if.end9:
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ret void
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}
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; A != B implies A == B is false
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; CHECK-LABEL: @test_ne
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; CHECK-NOT: dead
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; CHECK: ret void
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define void @test_ne(i32 %a, i32 %b) {
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entry:
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%cmp = icmp ne i32 %a, %b
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br i1 %cmp, label %if.then, label %if.end3
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if.then:
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%cmp1 = icmp eq i32 %a, %b
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br i1 %cmp1, label %if.then2, label %if.end
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if.then2:
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call void @dead()
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br label %if.end
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if.end:
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br label %if.end3
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if.end3:
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ret void
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}
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; A >u B implies A == B is false.
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; A >u B implies A <=u B is false.
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; A >u B implies A != B is true.
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; CHECK-LABEL: @test_ugt
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; CHECK-NOT: dead
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; CHECK: alive
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; CHECK-NOT: dead
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; CHECK: ret void
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define void @test_ugt(i32 %a, i32 %b) {
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entry:
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%cmp = icmp ugt i32 %a, %b
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br i1 %cmp, label %if.then, label %if.end9
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if.then:
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%cmp1 = icmp eq i32 %a, %b
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br i1 %cmp1, label %if.then2, label %if.end
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if.then2:
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call void @dead()
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br label %if.end
|
||||
|
||||
if.end:
|
||||
%cmp3 = icmp ule i32 %a, %b
|
||||
br i1 %cmp3, label %if.then4, label %if.end5
|
||||
|
||||
if.then4:
|
||||
call void @dead()
|
||||
br label %if.end5
|
||||
|
||||
if.end5:
|
||||
%cmp6 = icmp ne i32 %a, %b
|
||||
br i1 %cmp6, label %if.then7, label %if.end8
|
||||
|
||||
if.then7:
|
||||
call void @alive()
|
||||
br label %if.end8
|
||||
|
||||
if.end8:
|
||||
br label %if.end9
|
||||
|
||||
if.end9:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A >s B implies A == B is false.
|
||||
; A >s B implies A <=s B is false.
|
||||
; A >s B implies A != B is true.
|
||||
; CHECK-LABEL: @test_sgt
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: alive
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_sgt(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp sgt i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end9
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp eq i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
%cmp3 = icmp sle i32 %a, %b
|
||||
br i1 %cmp3, label %if.then4, label %if.end5
|
||||
|
||||
if.then4:
|
||||
call void @dead()
|
||||
br label %if.end5
|
||||
|
||||
if.end5:
|
||||
%cmp6 = icmp ne i32 %a, %b
|
||||
br i1 %cmp6, label %if.then7, label %if.end8
|
||||
|
||||
if.then7:
|
||||
call void @alive()
|
||||
br label %if.end8
|
||||
|
||||
if.end8:
|
||||
br label %if.end9
|
||||
|
||||
if.end9:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A <u B implies A == B is false.
|
||||
; A <u B implies A >=u B is false.
|
||||
; A <u B implies A != B is true.
|
||||
; CHECK-LABEL: @test_ult
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: alive
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_ult(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp ult i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end9
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp eq i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
%cmp3 = icmp uge i32 %a, %b
|
||||
br i1 %cmp3, label %if.then4, label %if.end5
|
||||
|
||||
if.then4:
|
||||
call void @dead()
|
||||
br label %if.end5
|
||||
|
||||
if.end5:
|
||||
%cmp6 = icmp eq i32 %a, %b
|
||||
br i1 %cmp6, label %if.end8, label %if.then7
|
||||
|
||||
if.then7:
|
||||
call void @alive()
|
||||
br label %if.end8
|
||||
|
||||
if.end8:
|
||||
br label %if.end9
|
||||
|
||||
if.end9:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A <s B implies A == B is false.
|
||||
; A <s B implies A >=s B is false.
|
||||
; A <s B implies A != B is true.
|
||||
; CHECK-LABEL: @test_slt
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: alive
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_slt(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp slt i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end9
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp eq i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
%cmp3 = icmp sge i32 %a, %b
|
||||
br i1 %cmp3, label %if.then4, label %if.end5
|
||||
|
||||
if.then4:
|
||||
call void @dead()
|
||||
br label %if.end5
|
||||
|
||||
if.end5:
|
||||
%cmp6 = icmp eq i32 %a, %b
|
||||
br i1 %cmp6, label %if.end8, label %if.then7
|
||||
|
||||
if.then7:
|
||||
call void @alive()
|
||||
br label %if.end8
|
||||
|
||||
if.end8:
|
||||
br label %if.end9
|
||||
|
||||
if.end9:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A >=u B implies A <u B is false.
|
||||
; CHECK-LABEL: @test_uge
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_uge(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp uge i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end3
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp ult i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
br label %if.end3
|
||||
|
||||
if.end3:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A >=s B implies A <s B is false.
|
||||
; CHECK-LABEL: @test_sge
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_sge(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp sge i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end3
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp slt i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
br label %if.end3
|
||||
|
||||
if.end3:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A <=u B implies A >u B is false.
|
||||
; CHECK-LABEL: @test_ule
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_ule(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end3
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp ugt i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
br label %if.end3
|
||||
|
||||
if.end3:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A <=s B implies A >s B is false.
|
||||
; CHECK-LABEL: @test_sle
|
||||
; CHECK-NOT: dead
|
||||
; CHECK: ret void
|
||||
define void @test_sle(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp sle i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end3
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp sgt i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @dead()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
br label %if.end3
|
||||
|
||||
if.end3:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A u<= B does not imply A s> B is false.
|
||||
; CHECK-LABEL: @test_ule_sgt_unsafe
|
||||
; CHECK: alive
|
||||
; CHECK: ret void
|
||||
define void @test_ule_sgt_unsafe(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp ule i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end3
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp sgt i32 %a, %b
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @alive()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
br label %if.end3
|
||||
|
||||
if.end3:
|
||||
ret void
|
||||
}
|
||||
|
||||
; A u> B does not imply B s> A is false.
|
||||
; CHECK-LABEL: @test_ugt_sgt_unsafe
|
||||
; CHECK: alive
|
||||
; CHECK: ret void
|
||||
define void @test_ugt_sgt_unsafe(i32 %a, i32 %b) {
|
||||
entry:
|
||||
%cmp = icmp ugt i32 %a, %b
|
||||
br i1 %cmp, label %if.then, label %if.end3
|
||||
|
||||
if.then:
|
||||
%cmp1 = icmp sgt i32 %b, %a
|
||||
br i1 %cmp1, label %if.then2, label %if.end
|
||||
|
||||
if.then2:
|
||||
call void @alive()
|
||||
br label %if.end
|
||||
|
||||
if.end:
|
||||
br label %if.end3
|
||||
|
||||
if.end3:
|
||||
ret void
|
||||
}
|
||||
|
||||
declare void @dead()
|
||||
declare void @alive()
|
||||
Loading…
Reference in New Issue
Block a user