diff options
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 9 | ||||
| -rw-r--r-- | test/Analysis/ScalarEvolution/xor-and.ll | 11 |
2 files changed, 17 insertions, 3 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 3731fdfc71..2546e81952 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -2453,9 +2453,12 @@ SCEVHandle ScalarEvolution::createSCEV(Value *V) { if (BO->getOpcode() == Instruction::And && LCI->getValue() == CI->getValue()) if (const SCEVZeroExtendExpr *Z = - dyn_cast<SCEVZeroExtendExpr>(getSCEV(U->getOperand(0)))) - return getZeroExtendExpr(getNotSCEV(Z->getOperand()), - U->getType()); + dyn_cast<SCEVZeroExtendExpr>(getSCEV(U->getOperand(0)))) { + SCEVHandle ZO = Z->getOperand(); + if (APIntOps::isMask(getTypeSizeInBits(ZO->getType()), + CI->getValue())) + return getZeroExtendExpr(getNotSCEV(ZO), U->getType()); + } } break; diff --git a/test/Analysis/ScalarEvolution/xor-and.ll b/test/Analysis/ScalarEvolution/xor-and.ll new file mode 100644 index 0000000000..9b02bb803f --- /dev/null +++ b/test/Analysis/ScalarEvolution/xor-and.ll @@ -0,0 +1,11 @@ +; RUN: llvm-as < %s | opt -scalar-evolution -disable-output -analyze | grep {\\--> %z} + +; ScalarEvolution shouldn't try to analyze %s into something like +; --> (zext i4 (-1 + (-1 * (trunc i64 (8 * %x) to i4))) to i64) + +define i64 @foo(i64 %x) { + %a = shl i64 %x, 3 + %t = and i64 %a, 8 + %z = xor i64 %t, 8 + ret i64 %z +} |