diff options
| author | Chad Rosier <mcrosier@apple.com> | 2012-03-02 02:50:46 +0000 |
|---|---|---|
| committer | Chad Rosier <mcrosier@apple.com> | 2012-03-02 02:50:46 +0000 |
| commit | 74bab7f597b24d847175f8550002d8a014f63c8c (patch) | |
| tree | 6cf987b03e7b39b0d9b6ef1d8e7168a6b606c446 /lib | |
| parent | b83e2bbfbc107a71632bd42f2be8186554b16e1f (diff) | |
Prevent obscure and incorrect tail-call optimization.
In this instance we are generating the tail-call during legalizeDAG. The 2nd
floor call can't be a tail call because it clobbers %xmm1, which is defined by
the first floor call. The first floor call can't be a tail-call because it's
not in the tail position. The only reasonable way I could think to fix this
in a target-independent manner was to check for glue logic on the copy reg.
rdar://10930395
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151877 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index 4ad179ead6..d1ded33384 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -1589,6 +1589,11 @@ bool X86TargetLowering::isUsedByReturnOnly(SDNode *N) const { Copy->getOpcode() != ISD::FP_EXTEND) return false; + // If anything is glued to the copy, then we can't safely perform a tail call. + if (Copy->getOpcode() == ISD::CopyToReg && + Copy->getNumOperands() == 4) + return false; + bool HasRet = false; for (SDNode::use_iterator UI = Copy->use_begin(), UE = Copy->use_end(); UI != UE; ++UI) { |