Fix a XOR reassociation bug.
When Reassociator optimize "(x | C1)" ^ "(X & C2)", it may swap the two
subexpressions, however, it forgot to swap cached constants (of C1 and C2)
accordingly.
rdar://13739160
llvm-svn: 180676
diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp
index fc3b38e..a3c241d 100644
--- a/llvm/lib/Transforms/Scalar/Reassociate.cpp
+++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp
@@ -1195,9 +1195,6 @@
if (X != Opnd2->getSymbolicPart())
return false;
- const APInt &C1 = Opnd1->getConstPart();
- const APInt &C2 = Opnd2->getConstPart();
-
// This many instruction become dead.(At least "Opnd1 ^ Opnd2" will die.)
int DeadInstNum = 1;
if (Opnd1->getValue()->hasOneUse())
@@ -1215,6 +1212,8 @@
if (Opnd2->isOrExpr())
std::swap(Opnd1, Opnd2);
+ const APInt &C1 = Opnd1->getConstPart();
+ const APInt &C2 = Opnd2->getConstPart();
APInt C3((~C1) ^ C2);
// Do not increase code size!
@@ -1230,6 +1229,8 @@
} else if (Opnd1->isOrExpr()) {
// Xor-Rule 3: (x | c1) ^ (x | c2) = (x & c3) ^ c3 where c3 = c1 ^ c2
//
+ const APInt &C1 = Opnd1->getConstPart();
+ const APInt &C2 = Opnd2->getConstPart();
APInt C3 = C1 ^ C2;
// Do not increase code size
@@ -1244,6 +1245,8 @@
} else {
// Xor-Rule 4: (x & c1) ^ (x & c2) = (x & (c1^c2))
//
+ const APInt &C1 = Opnd1->getConstPart();
+ const APInt &C2 = Opnd2->getConstPart();
APInt C3 = C1 ^ C2;
Res = createAndInstr(I, X, C3);
}