From 4264e7e46fe96a516a305b9c684e79ba5de2c9e5 Mon Sep 17 00:00:00 2001 From: Eric Christopher Date: Tue, 2 Feb 2010 22:10:43 +0000 Subject: Re-add strcmp and known size object size checking optimization. Passed bootstrap and nightly test run here. llvm-svn: 95145 --- llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp') diff --git a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp index db6ff29200f..4216e8f995c 100644 --- a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp +++ b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp @@ -1213,8 +1213,13 @@ struct StrCpyChkOpt : public LibCallOptimization { if (!SizeCI) return 0; - // We don't have any length information, just lower to a plain strcpy. - if (SizeCI->isAllOnesValue()) + // If a) we don't have any length information, or b) we know this will + // fit then just lower to a plain strcpy. Otherwise we'll keep our + // strcpy_chk call which may fail at runtime if the size is too long. + // TODO: It might be nice to get a maximum length out of the possible + // string lengths for varying. + if (SizeCI->isAllOnesValue() || + SizeCI->getZExtValue() >= GetStringLength(CI->getOperand(2))) return EmitStrCpy(CI->getOperand(1), CI->getOperand(2), B); return 0; -- cgit v1.2.3