return Res;
}
- // (icmp ne/eq (sub A B) 0) -> (icmp ne/eq A, B)
- if (I.isEquality() && CI->isZero() &&
- match(Op0, m_Sub(m_Value(A), m_Value(B)))) {
- // (icmp cond A B) if cond is equality
- return new ICmpInst(I.getPredicate(), A, B);
- }
-
- // (icmp sgt (sub nsw A B), -1) -> (icmp sge A, B)
- if (I.getPredicate() == ICmpInst::ICMP_SGT && CI->isAllOnesValue() &&
- match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
- return new ICmpInst(ICmpInst::ICMP_SGE, A, B);
-
- // (icmp sgt (sub nsw A B), 0) -> (icmp sgt A, B)
- if (I.getPredicate() == ICmpInst::ICMP_SGT && CI->isZero() &&
- match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
- return new ICmpInst(ICmpInst::ICMP_SGT, A, B);
-
- // (icmp slt (sub nsw A B), 0) -> (icmp slt A, B)
- if (I.getPredicate() == ICmpInst::ICMP_SLT && CI->isZero() &&
- match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
- return new ICmpInst(ICmpInst::ICMP_SLT, A, B);
-
- // (icmp slt (sub nsw A B), 1) -> (icmp sle A, B)
- if (I.getPredicate() == ICmpInst::ICMP_SLT && CI->isOne() &&
- match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
- return new ICmpInst(ICmpInst::ICMP_SLE, A, B);
+ // The following transforms are only 'worth it' if the only user of the
+ // subtraction is the icmp.
+ if (Op0->hasOneUse()) {
+ // (icmp ne/eq (sub A B) 0) -> (icmp ne/eq A, B)
+ if (I.isEquality() && CI->isZero() &&
+ match(Op0, m_Sub(m_Value(A), m_Value(B))))
+ return new ICmpInst(I.getPredicate(), A, B);
+
+ // (icmp sgt (sub nsw A B), -1) -> (icmp sge A, B)
+ if (I.getPredicate() == ICmpInst::ICMP_SGT && CI->isAllOnesValue() &&
+ match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
+ return new ICmpInst(ICmpInst::ICMP_SGE, A, B);
+
+ // (icmp sgt (sub nsw A B), 0) -> (icmp sgt A, B)
+ if (I.getPredicate() == ICmpInst::ICMP_SGT && CI->isZero() &&
+ match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
+ return new ICmpInst(ICmpInst::ICMP_SGT, A, B);
+
+ // (icmp slt (sub nsw A B), 0) -> (icmp slt A, B)
+ if (I.getPredicate() == ICmpInst::ICMP_SLT && CI->isZero() &&
+ match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
+ return new ICmpInst(ICmpInst::ICMP_SLT, A, B);
+
+ // (icmp slt (sub nsw A B), 1) -> (icmp sle A, B)
+ if (I.getPredicate() == ICmpInst::ICMP_SLT && CI->isOne() &&
+ match(Op0, m_NSWSub(m_Value(A), m_Value(B))))
+ return new ICmpInst(ICmpInst::ICMP_SLE, A, B);
+ }
// If we have an icmp le or icmp ge instruction, turn it into the
// appropriate icmp lt or icmp gt instruction. This allows us to rely on
%v = icmp sle i64 %t, 0
ret i1 %v
}
+
+; CHECK-LABEL: @f5
+; CHECK: %[[cmp:.*]] = icmp slt i32 %[[sub:.*]], 0
+; CHECK: %[[neg:.*]] = sub nsw i32 0, %[[sub]]
+; CHECK: %[[sel:.*]] = select i1 %[[cmp]], i32 %[[neg]], i32 %[[sub]]
+; CHECK: ret i32 %[[sel]]
+define i32 @f5(i8 %a, i8 %b) {
+ %conv = zext i8 %a to i32
+ %conv3 = zext i8 %b to i32
+ %sub = sub nsw i32 %conv, %conv3
+ %cmp4 = icmp slt i32 %sub, 0
+ %sub7 = sub nsw i32 0, %sub
+ %sub7.sub = select i1 %cmp4, i32 %sub7, i32 %sub
+ ret i32 %sub7.sub
+}