diff --git a/lib/CodeGen/RegAllocFast.cpp b/lib/CodeGen/RegAllocFast.cpp index 7ac38598c3a..4664a3c4299 100644 --- a/lib/CodeGen/RegAllocFast.cpp +++ b/lib/CodeGen/RegAllocFast.cpp @@ -682,7 +682,7 @@ void RAFast::handleThroughOperands(MachineInstr *MI, } SmallVector PartialDefs; - DEBUG(dbgs() << "Allocating tied uses and early clobbers.\n"); + DEBUG(dbgs() << "Allocating tied uses.\n"); for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { MachineOperand &MO = MI->getOperand(i); if (!MO.isReg()) continue; @@ -704,15 +704,24 @@ void RAFast::handleThroughOperands(MachineInstr *MI, // That would confuse the later phys-def processing pass. LiveRegMap::iterator LRI = reloadVirtReg(MI, i, Reg, 0); PartialDefs.push_back(LRI->second.PhysReg); - } else if (MO.isEarlyClobber()) { - // Note: defineVirtReg may invalidate MO. - LiveRegMap::iterator LRI = defineVirtReg(MI, i, Reg, 0); - unsigned PhysReg = LRI->second.PhysReg; - if (setPhysReg(MI, i, PhysReg)) - VirtDead.push_back(Reg); } } + DEBUG(dbgs() << "Allocating early clobbers.\n"); + for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { + MachineOperand &MO = MI->getOperand(i); + if (!MO.isReg()) continue; + unsigned Reg = MO.getReg(); + if (!TargetRegisterInfo::isVirtualRegister(Reg)) continue; + if (!MO.isEarlyClobber()) + continue; + // Note: defineVirtReg may invalidate MO. + LiveRegMap::iterator LRI = defineVirtReg(MI, i, Reg, 0); + unsigned PhysReg = LRI->second.PhysReg; + if (setPhysReg(MI, i, PhysReg)) + VirtDead.push_back(Reg); + } + // Restore UsedInInstr to a state usable for allocating normal virtual uses. UsedInInstr.reset(); for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { diff --git a/test/CodeGen/X86/pr11415.ll b/test/CodeGen/X86/pr11415.ll new file mode 100644 index 00000000000..92c530bb9e7 --- /dev/null +++ b/test/CodeGen/X86/pr11415.ll @@ -0,0 +1,23 @@ +; RUN: llc %s -o - -regalloc=fast | FileCheck %s + +; We used to consider the early clobber in the second asm statement as +; defining %0 before it was read. This caused us to omit the +; movq -8(%rsp), %rdx + +; CHECK: #APP +; CHECK-NEXT: #NO_APP +; CHECK-NEXT: movq %rcx, %rax +; CHECK-NEXT: movq %rax, -8(%rsp) +; CHECK-NEXT: movq -8(%rsp), %rdx +; CHECK-NEXT: #APP +; CHECK-NEXT: #NO_APP +; CHECK-NEXT: movq %rdx, %rax +; CHECK-NEXT: movq %rdx, -8(%rsp) +; CHECK-NEXT: ret + +define i64 @foo() { +entry: + %0 = tail call i64 asm "", "={cx}"() nounwind + %1 = tail call i64 asm "", "=&r,0,r,~{rax}"(i64 %0, i64 %0) nounwind + ret i64 %1 +}