[llvm] r266987 - Refactor implied condition logic from ValueTracking directly into CmpInst. NFC.
Chad Rosier via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 21 07:04:56 PDT 2016
Author: mcrosier
Date: Thu Apr 21 09:04:54 2016
New Revision: 266987
URL: http://llvm.org/viewvc/llvm-project?rev=266987&view=rev
Log:
Refactor implied condition logic from ValueTracking directly into CmpInst. NFC.
Differential Revision: http://reviews.llvm.org/D19330
Modified:
llvm/trunk/include/llvm/IR/InstrTypes.h
llvm/trunk/lib/Analysis/ValueTracking.cpp
llvm/trunk/lib/IR/Instructions.cpp
Modified: llvm/trunk/include/llvm/IR/InstrTypes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/InstrTypes.h?rev=266987&r1=266986&r2=266987&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/InstrTypes.h (original)
+++ llvm/trunk/include/llvm/IR/InstrTypes.h Thu Apr 21 09:04:54 2016
@@ -1067,6 +1067,18 @@ public:
return isFalseWhenEqual(getPredicate());
}
+ /// @brief Determine if Pred1 implies Pred2 is true when two compares have
+ /// matching operands.
+ bool isTrueWhenOperandsMatch(Predicate Pred2) {
+ return isTrueWhenOperandsMatch(getPredicate(), Pred2);
+ }
+
+ /// @brief Determine if Pred1 implies Pred2 is false when two compares have
+ /// matching operands.
+ bool isFalseWhenOperandsMatch(Predicate Pred2) {
+ return isFalseWhenOperandsMatch(getPredicate(), Pred2);
+ }
+
/// @returns true if the predicate is unsigned, false otherwise.
/// @brief Determine if the predicate is an unsigned operation.
static bool isUnsigned(Predicate predicate);
@@ -1087,6 +1099,14 @@ public:
/// Determine if the predicate is false when comparing a value with itself.
static bool isFalseWhenEqual(Predicate predicate);
+ /// Determine if Pred1 implies Pred2 is true when two compares have matching
+ /// operands.
+ static bool isTrueWhenOperandsMatch(Predicate Pred1, Predicate Pred2);
+
+ /// Determine if Pred1 implies Pred2 is false when two compares have matching
+ /// operands.
+ static bool isFalseWhenOperandsMatch(Predicate Pred1, Predicate Pred2);
+
/// @brief Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Instruction *I) {
return I->getOpcode() == Instruction::ICmp ||
Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=266987&r1=266986&r2=266987&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Thu Apr 21 09:04:54 2016
@@ -3935,61 +3935,11 @@ static Optional<bool> isImpliedCondMatch
std::swap(BLHS, BRHS);
BPred = ICmpInst::getSwappedPredicate(BPred);
}
-
- // If the predicates match, then we know the first condition implies the
- // second is true.
- if (APred == BPred)
+ if (CmpInst::isTrueWhenOperandsMatch(APred, BPred))
return true;
-
- // If an inverted APred matches BPred, we can infer the second condition is
- // false.
- if (CmpInst::getInversePredicate(APred) == BPred)
+ if (CmpInst::isFalseWhenOperandsMatch(APred, BPred))
return false;
- // If a swapped APred matches BPred, we can infer the second condition is
- // false in many cases.
- if (CmpInst::getSwappedPredicate(APred) == BPred) {
- switch (APred) {
- default:
- break;
- case CmpInst::ICMP_UGT: // A >u B implies A <u B is false.
- case CmpInst::ICMP_ULT: // A <u B implies A >u B is false.
- case CmpInst::ICMP_SGT: // A >s B implies A <s B is false.
- case CmpInst::ICMP_SLT: // A <s B implies A >s B is false.
- return false;
- }
- }
-
- // The predicates must match sign or at least one of them must be an equality
- // comparison (which is signless).
- if (ICmpInst::isSigned(APred) != ICmpInst::isSigned(BPred) &&
- !ICmpInst::isEquality(APred) && !ICmpInst::isEquality(BPred))
- return None;
-
- switch (APred) {
- default:
- break;
- case CmpInst::ICMP_EQ:
- // A == B implies A > B and A < B are false.
- if (CmpInst::isFalseWhenEqual(BPred))
- return false;
-
- break;
- case CmpInst::ICMP_UGT:
- case CmpInst::ICMP_ULT:
- case CmpInst::ICMP_SGT:
- case CmpInst::ICMP_SLT:
- // A > B implies A == B is false.
- // A < B implies A == B is false.
- if (BPred == CmpInst::ICMP_EQ)
- return false;
-
- // A > B implies A != B is true.
- // A < B implies A != B is true.
- if (BPred == CmpInst::ICMP_NE)
- return true;
- break;
- }
return None;
}
Modified: llvm/trunk/lib/IR/Instructions.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Instructions.cpp?rev=266987&r1=266986&r2=266987&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Instructions.cpp (original)
+++ llvm/trunk/lib/IR/Instructions.cpp Thu Apr 21 09:04:54 2016
@@ -3597,6 +3597,58 @@ bool CmpInst::isFalseWhenEqual(Predicate
}
}
+bool CmpInst::isTrueWhenOperandsMatch(Predicate Pred1, Predicate Pred2) {
+ // If the predicates match, then we know the first condition implies the
+ // second is true.
+ if (Pred1 == Pred2)
+ return true;
+
+ switch (Pred1) {
+ default:
+ break;
+ case ICMP_UGT: // A >u B implies A != B is true.
+ case ICMP_ULT: // A <u B implies A != B is true.
+ case ICMP_SGT: // A >s B implies A != B is true.
+ case ICMP_SLT: // A <s B implies A != B is true.
+ return Pred2 == ICMP_NE;
+ }
+ return false;
+}
+
+bool CmpInst::isFalseWhenOperandsMatch(Predicate Pred1, Predicate Pred2) {
+ // If an inverted Pred1 matches Pred2, we can infer the second condition is
+ // false.
+ if (getInversePredicate(Pred1) == Pred2)
+ return true;
+
+ // If a swapped Pred1 matches Pred2, we can infer the second condition is
+ // false in many cases.
+ if (getSwappedPredicate(Pred1) == Pred2) {
+ switch (Pred1) {
+ default:
+ break;
+ case ICMP_UGT: // A >u B implies A <u B is false.
+ case ICMP_ULT: // A <u B implies A >u B is false.
+ case ICMP_SGT: // A >s B implies A <s B is false.
+ case ICMP_SLT: // A <s B implies A >s B is false.
+ return true;
+ }
+ }
+ // A == B implies A > B and A < B are false.
+ if (Pred1 == ICMP_EQ && isFalseWhenEqual(Pred2))
+ return true;
+
+ switch (Pred1) {
+ default:
+ break;
+ case ICMP_UGT: // A >u B implies A == B is false.
+ case ICMP_ULT: // A <u B implies A == B is false.
+ case ICMP_SGT: // A >s B implies A == B is false.
+ case ICMP_SLT: // A <s B implies A == B is false.
+ return Pred2 == ICMP_EQ;
+ }
+ return false;
+}
//===----------------------------------------------------------------------===//
// SwitchInst Implementation
More information about the llvm-commits
mailing list