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-rw-r--r--llvm/lib/Transforms/Utils/SimplifyCFG.cpp25
1 files changed, 25 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 43e823d..7c0f85c 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -461,6 +461,9 @@ private:
QUERY( (y & ~mask = y) =>
((x & ~mask = y) <=> (x = y OR x = (y | mask)))
);
+ QUERY( (y | mask = y) =>
+ ((x | mask = y) <=> (x = y OR x = (y & ~mask)))
+ );
*/
// Please note that each pattern must be a dual implication (<--> or
@@ -503,6 +506,28 @@ private:
}
}
+ // Pattern match a special case:
+ /*
+ QUERY( (y | mask = y) =>
+ ((x | mask = y) <=> (x = y OR x = (y & ~mask)))
+ );
+ */
+ if (match(ICI->getOperand(0),
+ m_Or(m_Value(RHSVal), m_APInt(RHSC)))) {
+ APInt Mask = *RHSC;
+ if (Mask.isPowerOf2() && (C->getValue() | Mask) == C->getValue()) {
+ // If we already have a value for the switch, it has to match!
+ if (!setValueOnce(RHSVal))
+ return false;
+
+ Vals.push_back(C);
+ Vals.push_back(ConstantInt::get(C->getContext(),
+ C->getValue() & ~Mask));
+ UsedICmps++;
+ return true;
+ }
+ }
+
// If we already have a value for the switch, it has to match!
if (!setValueOnce(ICI->getOperand(0)))
return false;