From 20900cae35c0d18eed449a985d452a74c98ecdb2 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Wed, 22 Apr 2009 16:20:48 +0000 Subject: [PATCH] Simplify trivial cast-of-cast SCEVs. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69809 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ScalarEvolution.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 75331fdab49..cebf4d704fe 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -654,6 +654,10 @@ SCEVHandle ScalarEvolution::getTruncateExpr(const SCEVHandle &Op, const Type *Ty return getUnknown( ConstantExpr::getTrunc(SC->getValue(), Ty)); + // trunc(trunc(x)) --> trunc(x) + if (SCEVTruncateExpr *ST = dyn_cast(Op)) + return getTruncateExpr(ST->getOperand(), Ty); + // If the input value is a chrec scev made out of constants, truncate // all of the constants. if (SCEVAddRecExpr *AddRec = dyn_cast(Op)) { @@ -685,6 +689,10 @@ SCEVHandle ScalarEvolution::getZeroExtendExpr(const SCEVHandle &Op, return getUnknown(C); } + // zext(zext(x)) --> zext(x) + if (SCEVZeroExtendExpr *SZ = dyn_cast(Op)) + return getZeroExtendExpr(SZ->getOperand(), Ty); + // FIXME: If the input value is a chrec scev, and we can prove that the value // did not overflow the old, smaller, value, we can zero extend all of the // operands (often constants). This would allow analysis of something like @@ -706,6 +714,10 @@ SCEVHandle ScalarEvolution::getSignExtendExpr(const SCEVHandle &Op, const Type * return getUnknown(C); } + // sext(sext(x)) --> sext(x) + if (SCEVSignExtendExpr *SS = dyn_cast(Op)) + return getSignExtendExpr(SS->getOperand(), Ty); + // FIXME: If the input value is a chrec scev, and we can prove that the value // did not overflow the old, smaller, value, we can sign extend all of the // operands (often constants). This would allow analysis of something like