Index: lib/Target/PowerPC/PPCFrameLowering.cpp =================================================================== --- lib/Target/PowerPC/PPCFrameLowering.cpp +++ lib/Target/PowerPC/PPCFrameLowering.cpp @@ -573,10 +573,18 @@ RS.initRegState(); RS.enterBasicBlock(MBB); - // The scratch register will be used at the end of the block, so must consider - // all registers used within the block - if (UseAtEnd && MBB->begin() != MBB->getFirstTerminator()) - RS.forward(MBB->getFirstTerminator()); + if (UseAtEnd && !MBB->empty()) { + // The scratch register will be used at the end of the block, so must consider + // all registers used within the block + + MachineBasicBlock::iterator MBBI = MBB->getFirstTerminator(); + // If no terminator, back iterator up to previous instruction + if (MBBI == MBB->end()) + MBBI = std::prev(MBBI); + + if (MBBI != MBB->begin()) + RS.forward(MBBI); + } if (!RS.isRegUsed(R0)) return true; @@ -1768,6 +1776,6 @@ } bool PPCFrameLowering::enableShrinkWrapping(const MachineFunction &MF) const { - // FIXME: Enable this for non-Darwin PPC64 once it is confirmed working. - return false; + return (MF.getSubtarget().isSVR4ABI() && + MF.getSubtarget().isPPC64()); } Index: test/CodeGen/PowerPC/ppc-shrink-wrapping.ll =================================================================== --- test/CodeGen/PowerPC/ppc-shrink-wrapping.ll +++ test/CodeGen/PowerPC/ppc-shrink-wrapping.ll @@ -1,6 +1,5 @@ ; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr8 %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=ENABLE ; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu %s -o - -enable-shrink-wrap=false | FileCheck %s --check-prefix=CHECK --check-prefix=DISABLE -; XFAIL: * ; ; Note: Lots of tests use inline asm instead of regular calls. ; This allows to have a better control on what the allocation will do.