This is an update to a previous commit (r181216).
The earlier change list introduced the following inst combines:
B * (uitofp i1 C) —> select C, B, 0
A * (1 - uitofp i1 C) —> select C, 0, A
select C, 0, B + select C, A, 0 —> select C, A, B
Together these 3 changes would simplify :
A * (1 - uitofp i1 C) + B * uitofp i1 C
down to :
select C, B, A
In practice we found that the first two substitutions can have a
negative effect on performance, because they reduce opportunities to
use FMA contractions; between the two options FMAs are often the
better choice. This change list amends the previous one to enable
just these inst combines:
select C, B, 0 + select C, 0, A —> select C, B, A
A * (1 - uitofp i1 C) + B * uitofp i1 C —> select C, B, A
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182499 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 166f8df..a2c545f 100644
--- a/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1262,6 +1262,49 @@
}
}
+ // A * (1 - uitofp i1 C) + B * (uitofp i1 C) -> select C, B, A
+ {
+ if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
+ Value *M1L, *M1R, *M2L, *M2R;
+ if (match(LHS, m_FMul(m_Value(M1L), m_Value(M1R))) &&
+ match(RHS, m_FMul(m_Value(M2L), m_Value(M2R)))) {
+
+ Value *A, *B, *C1, *C2;
+ if (!match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))))
+ std::swap(M1L, M1R);
+ if (!match(M2R, m_UIToFp(m_Value(C2))))
+ std::swap(M2L, M2R);
+
+ if (match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))) &&
+ match(M2R, m_UIToFp(m_Value(C2))) &&
+ C2->getType()->isIntegerTy(1) &&
+ C1 == C2) {
+ A = M1L;
+ B = M2L;
+ return SelectInst::Create(C1, B, A);
+ }
+
+ std::swap(M1L, M2L);
+ std::swap(M1R, M2R);
+
+ if (!match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))))
+ std::swap(M1L, M1R);
+ if (!match(M2R, m_UIToFp(m_Value(C2))))
+ std::swap(M2L, M2R);
+
+ if (match(M1R, m_FSub(m_FPOne(), m_UIToFp(m_Value(C1)))) &&
+ match(M2R, m_UIToFp(m_Value(C2))) &&
+ C2->getType()->isIntegerTy(1) &&
+ C1 == C2) {
+ A = M1L;
+ B = M2L;
+ return SelectInst::Create(C1, B, A);
+ }
+ }
+ }
+ }
+
+
if (I.hasUnsafeAlgebra()) {
if (Value *V = FAddCombine(Builder).simplify(&I))
return ReplaceInstUsesWith(I, V);