rdar://12753946
Implement rule : "x * (select cond 1.0, 0.0) -> select cond x, 0.0"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170226 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index b95da85..964297a 100644
--- a/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -341,6 +341,38 @@
}
}
+ // X * cond ? 1.0 : 0.0 => cond ? X : 0.0
+ if (I.hasNoNaNs() && I.hasNoSignedZeros()) {
+ Value *V0 = I.getOperand(0);
+ Value *V1 = I.getOperand(1);
+ Value *Cond, *SLHS, *SRHS;
+ bool Match = false;
+
+ if (match(V0, m_Select(m_Value(Cond), m_Value(SLHS), m_Value(SRHS)))) {
+ Match = true;
+ } else if (match(V1, m_Select(m_Value(Cond), m_Value(SLHS),
+ m_Value(SRHS)))) {
+ Match = true;
+ std::swap(V0, V1);
+ }
+
+ if (Match) {
+ ConstantFP *C0 = dyn_cast<ConstantFP>(SLHS);
+ ConstantFP *C1 = dyn_cast<ConstantFP>(SRHS);
+
+ if (C0 && C1 &&
+ ((C0->isZero() && C1->isExactlyValue(1.0)) ||
+ (C1->isZero() && C0->isExactlyValue(1.0)))) {
+ Value *T;
+ if (C0->isZero())
+ T = Builder->CreateSelect(Cond, SLHS, V1);
+ else
+ T = Builder->CreateSelect(Cond, V1, SRHS);
+ return ReplaceInstUsesWith(I, T);
+ }
+ }
+ }
+
return Changed ? &I : 0;
}