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Simplify trivial cast-of-cast SCEVs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69809 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -654,6 +654,10 @@ SCEVHandle ScalarEvolution::getTruncateExpr(const SCEVHandle &Op, const Type *Ty
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return getUnknown(
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ConstantExpr::getTrunc(SC->getValue(), Ty));
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// trunc(trunc(x)) --> trunc(x)
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if (SCEVTruncateExpr *ST = dyn_cast<SCEVTruncateExpr>(Op))
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return getTruncateExpr(ST->getOperand(), Ty);
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// If the input value is a chrec scev made out of constants, truncate
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// all of the constants.
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if (SCEVAddRecExpr *AddRec = dyn_cast<SCEVAddRecExpr>(Op)) {
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@ -685,6 +689,10 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op,
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return getUnknown(C);
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}
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// zext(zext(x)) --> zext(x)
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if (SCEVZeroExtendExpr *SZ = dyn_cast<SCEVZeroExtendExpr>(Op))
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return getZeroExtendExpr(SZ->getOperand(), Ty);
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// FIXME: If the input value is a chrec scev, and we can prove that the value
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// did not overflow the old, smaller, value, we can zero extend all of the
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// operands (often constants). This would allow analysis of something like
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@ -706,6 +714,10 @@ SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op, const Type *
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return getUnknown(C);
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}
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// sext(sext(x)) --> sext(x)
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if (SCEVSignExtendExpr *SS = dyn_cast<SCEVSignExtendExpr>(Op))
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return getSignExtendExpr(SS->getOperand(), Ty);
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// FIXME: If the input value is a chrec scev, and we can prove that the value
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// did not overflow the old, smaller, value, we can sign extend all of the
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// operands (often constants). This would allow analysis of something like
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