diff options
Diffstat (limited to 'llvm/lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | llvm/lib/Analysis/ValueTracking.cpp | 54 |
1 files changed, 14 insertions, 40 deletions
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp index 4f18cc8b117..660693077fe 100644 --- a/llvm/lib/Analysis/ValueTracking.cpp +++ b/llvm/lib/Analysis/ValueTracking.cpp @@ -3918,6 +3918,10 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred, Value *CmpLHS, Value *CmpRHS, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS) { + // Assume success. If there's no match, callers should not use these anyway. + LHS = TrueVal; + RHS = FalseVal; + // Recognize variations of: // CLAMP(v,l,h) ==> ((v) < (l) ? (l) : ((v) > (h) ? (h) : (v))) const APInt *C1; @@ -3926,35 +3930,23 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred, // (X <s C1) ? C1 : SMIN(X, C2) ==> SMAX(SMIN(X, C2), C1) if (match(FalseVal, m_SMin(m_Specific(CmpLHS), m_APInt(C2))) && - C1->slt(*C2) && Pred == CmpInst::ICMP_SLT) { - LHS = TrueVal; - RHS = FalseVal; + C1->slt(*C2) && Pred == CmpInst::ICMP_SLT) return {SPF_SMAX, SPNB_NA, false}; - } // (X >s C1) ? C1 : SMAX(X, C2) ==> SMIN(SMAX(X, C2), C1) if (match(FalseVal, m_SMax(m_Specific(CmpLHS), m_APInt(C2))) && - C1->sgt(*C2) && Pred == CmpInst::ICMP_SGT) { - LHS = TrueVal; - RHS = FalseVal; + C1->sgt(*C2) && Pred == CmpInst::ICMP_SGT) return {SPF_SMIN, SPNB_NA, false}; - } // (X <u C1) ? C1 : UMIN(X, C2) ==> UMAX(UMIN(X, C2), C1) if (match(FalseVal, m_UMin(m_Specific(CmpLHS), m_APInt(C2))) && - C1->ult(*C2) && Pred == CmpInst::ICMP_ULT) { - LHS = TrueVal; - RHS = FalseVal; + C1->ult(*C2) && Pred == CmpInst::ICMP_ULT) return {SPF_UMAX, SPNB_NA, false}; - } // (X >u C1) ? C1 : UMAX(X, C2) ==> UMIN(UMAX(X, C2), C1) if (match(FalseVal, m_UMax(m_Specific(CmpLHS), m_APInt(C2))) && - C1->ugt(*C2) && Pred == CmpInst::ICMP_UGT) { - LHS = TrueVal; - RHS = FalseVal; + C1->ugt(*C2) && Pred == CmpInst::ICMP_UGT) return {SPF_UMIN, SPNB_NA, false}; - } } if (Pred != CmpInst::ICMP_SGT && Pred != CmpInst::ICMP_SLT) @@ -3964,21 +3956,15 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred, // (X >s Y) ? 0 : Z ==> (Z >s 0) ? 0 : Z ==> SMIN(Z, 0) // (X <s Y) ? 0 : Z ==> (Z <s 0) ? 0 : Z ==> SMAX(Z, 0) if (match(TrueVal, m_Zero()) && - match(FalseVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS)))) { - LHS = TrueVal; - RHS = FalseVal; + match(FalseVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS)))) return {Pred == CmpInst::ICMP_SGT ? SPF_SMIN : SPF_SMAX, SPNB_NA, false}; - } // Z = X -nsw Y // (X >s Y) ? Z : 0 ==> (Z >s 0) ? Z : 0 ==> SMAX(Z, 0) // (X <s Y) ? Z : 0 ==> (Z <s 0) ? Z : 0 ==> SMIN(Z, 0) if (match(FalseVal, m_Zero()) && - match(TrueVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS)))) { - LHS = TrueVal; - RHS = FalseVal; + match(TrueVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS)))) return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false}; - } if (!match(CmpRHS, m_APInt(C1))) return {SPF_UNKNOWN, SPNB_NA, false}; @@ -3990,41 +3976,29 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred, // Is the sign bit set? // (X <s 0) ? X : MAXVAL ==> (X >u MAXVAL) ? X : MAXVAL ==> UMAX // (X <s 0) ? MAXVAL : X ==> (X >u MAXVAL) ? MAXVAL : X ==> UMIN - if (Pred == CmpInst::ICMP_SLT && *C1 == 0 && C2->isMaxSignedValue()) { - LHS = TrueVal; - RHS = FalseVal; + if (Pred == CmpInst::ICMP_SLT && *C1 == 0 && C2->isMaxSignedValue()) return {CmpLHS == TrueVal ? SPF_UMAX : SPF_UMIN, SPNB_NA, false}; - } // Is the sign bit clear? // (X >s -1) ? MINVAL : X ==> (X <u MINVAL) ? MINVAL : X ==> UMAX // (X >s -1) ? X : MINVAL ==> (X <u MINVAL) ? X : MINVAL ==> UMIN if (Pred == CmpInst::ICMP_SGT && C1->isAllOnesValue() && - C2->isMinSignedValue()) { - LHS = TrueVal; - RHS = FalseVal; + C2->isMinSignedValue()) 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) { - LHS = TrueVal; - RHS = FalseVal; + 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) { - LHS = TrueVal; - RHS = FalseVal; + 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}; } |
