From 1fa2f945ea6e8efef2e9f73833af5550f1b8a1ad Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Tue, 26 Mar 2013 21:20:15 +0000 Subject: [PATCH] Fix the register scavenger for targets that provide custom spilling As pointed out by Richard Sandiford, my recent updates to the register scavenger broke targets that use custom spilling (because the new code assumed that if there were no valid spill slots, than spilling would be impossible). I don't have a test case, but it should be possible to create one for Thumb 1, Mips 16, etc. llvm-svn: 178073 --- llvm/include/llvm/CodeGen/RegisterScavenging.h | 5 +++-- llvm/lib/CodeGen/RegisterScavenging.cpp | 7 +++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/llvm/include/llvm/CodeGen/RegisterScavenging.h b/llvm/include/llvm/CodeGen/RegisterScavenging.h index 0eb2b2ab07f7..49d16892f87a 100644 --- a/llvm/include/llvm/CodeGen/RegisterScavenging.h +++ b/llvm/include/llvm/CodeGen/RegisterScavenging.h @@ -42,7 +42,7 @@ class RegScavenger { /// Information on scavenged registers (held in a spill slot). struct ScavengedInfo { - ScavengedInfo(int FI) : FrameIndex(FI), Reg(0), Restore(NULL) {} + ScavengedInfo(int FI = -1) : FrameIndex(FI), Reg(0), Restore(NULL) {} /// A spill slot used for scavenging a register post register allocation. int FrameIndex; @@ -130,7 +130,8 @@ public: void getScavengingFrameIndices(SmallVectorImpl &A) const { for (SmallVector::const_iterator I = Scavenged.begin(), IE = Scavenged.end(); I != IE; ++I) - A.push_back(I->FrameIndex); + if (I->FrameIndex >= 0) + A.push_back(I->FrameIndex); } /// scavengeRegister - Make a register of the specific register class diff --git a/llvm/lib/CodeGen/RegisterScavenging.cpp b/llvm/lib/CodeGen/RegisterScavenging.cpp index 4c85644e1a35..6b85cd93cf32 100644 --- a/llvm/lib/CodeGen/RegisterScavenging.cpp +++ b/llvm/lib/CodeGen/RegisterScavenging.cpp @@ -371,8 +371,11 @@ unsigned RegScavenger::scavengeRegister(const TargetRegisterClass *RC, if (Scavenged[SI].Reg == 0) break; - assert(SI < Scavenged.size() && - "Scavenger slots are live, unable to scavenge another register!"); + if (SI < Scavenged.size()) { + // We need to scavenge a register but have no spill slot, the target + // must know how to do it (if not, we'll assert below). + Scavenged.push_back(ScavengedInfo()); + } // Avoid infinite regress Scavenged[SI].Reg = SReg;