From 6c70dc7842fdc036de1a49a8f62026f5cd6d0c23 Mon Sep 17 00:00:00 2001 From: Stephen Lin Date: Tue, 23 Apr 2013 16:31:56 +0000 Subject: Add some constraints to use of 'returned': 1) Disallow 'returned' on parameter that is also 'sret' (no sensible semantics, as far as I can tell). 2) Conservatively disallow tail calls through 'returned' parameters that also are 'zext' or 'sext' (for consistency with treatment of other zero-extending and sign-extending operations in tail call position detection...can be revised later to handle situations that can be determined to be safe). This is a new attribute that is not yet used, so there is no impact. llvm-svn: 180118 --- llvm/lib/CodeGen/Analysis.cpp | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'llvm/lib/CodeGen/Analysis.cpp') diff --git a/llvm/lib/CodeGen/Analysis.cpp b/llvm/lib/CodeGen/Analysis.cpp index 4731af5089a..e2b2067b0c6 100644 --- a/llvm/lib/CodeGen/Analysis.cpp +++ b/llvm/lib/CodeGen/Analysis.cpp @@ -269,6 +269,8 @@ static bool sameNoopInput(const Value *V1, const Value *V2, i != e; ++i) { unsigned attrInd = i - I->op_begin() + 1; if (cast(I)->paramHasAttr(attrInd, Attribute::Returned) && + !cast(I)->paramHasAttr(attrInd, Attribute::ZExt) && + !cast(I)->paramHasAttr(attrInd, Attribute::SExt) && isNoopBitcast((*i)->getType(), I->getType(), TLI)) { NoopInput = *i; break; @@ -282,6 +284,8 @@ static bool sameNoopInput(const Value *V1, const Value *V2, i != e; ++i) { unsigned attrInd = i - I->op_begin() + 1; if (cast(I)->paramHasAttr(attrInd, Attribute::Returned) && + !cast(I)->paramHasAttr(attrInd, Attribute::ZExt) && + !cast(I)->paramHasAttr(attrInd, Attribute::SExt) && isNoopBitcast((*i)->getType(), I->getType(), TLI)) { NoopInput = *i; break; -- cgit v1.2.3