From d9c9bd8485071afb22adcd2bb08f6a8e5e587ed6 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Wed, 24 Feb 2016 21:32:58 +0000 Subject: Vendor import of llvm release_38 branch r261684: https://llvm.org/svn/llvm-project/llvm/branches/release_38@261684 --- lib/CodeGen/RegAllocFast.cpp | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'lib/CodeGen/RegAllocFast.cpp') diff --git a/lib/CodeGen/RegAllocFast.cpp b/lib/CodeGen/RegAllocFast.cpp index f4c076fea0e7..8d7a7213ba07 100644 --- a/lib/CodeGen/RegAllocFast.cpp +++ b/lib/CodeGen/RegAllocFast.cpp @@ -1002,11 +1002,13 @@ void RAFast::AllocateBasicBlock() { unsigned DefOpEnd = MI->getNumOperands(); if (MI->isCall()) { - // Spill all virtregs before a call. This serves two purposes: 1. If an + // Spill all virtregs before a call. This serves one purpose: If an // exception is thrown, the landing pad is going to expect to find - // registers in their spill slots, and 2. we don't have to wade through - // all the operands on the call instruction. - DefOpEnd = VirtOpEnd; + // registers in their spill slots. + // Note: although this is appealing to just consider all definitions + // as call-clobbered, this is not correct because some of those + // definitions may be used later on and we do not want to reuse + // those for virtual registers in between. DEBUG(dbgs() << " Spilling remaining registers before call.\n"); spillAll(MI); -- cgit v1.2.3