diff options
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 31 | ||||
| -rw-r--r-- | test/CodeGen/X86/uint64-to-float.ll | 33 |
2 files changed, 33 insertions, 31 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index 658837c83b..2e8909a5c3 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -12059,6 +12059,31 @@ X86TargetLowering::EmitVAStartSaveXMMRegsWithCustomInserter( return EndMBB; } +// Check whether the given instruction should have had a kill marker on +// the EFLAGS operand. +static bool shouldHaveEFlagsKill(MachineBasicBlock::iterator SelectItr, + MachineBasicBlock* BB) { + for (MachineBasicBlock::iterator miI(next(SelectItr)), miE = BB->end(); + miI != miE; ++miI) { + const MachineInstr& mi = *miI; + if (mi.readsRegister(X86::EFLAGS)) { + return false; + } + if (mi.definesRegister(X86::EFLAGS)) { + // Should have kill-flag - update below. + break; + } + } + + // We found a def, or hit the end of the basic block. SelectMI should have a + // kill flag on EFLAGS. + MachineInstr& SelectMI = *SelectItr; + MachineOperand* EFlagsOp = SelectMI.findRegisterUseOperand(X86::EFLAGS); + assert(EFlagsOp != 0 && "No EFLAGS operand on select instruction?"); + EFlagsOp->setIsKill(); + return true; +} + MachineBasicBlock * X86TargetLowering::EmitLoweredSelect(MachineInstr *MI, MachineBasicBlock *BB) const { @@ -12089,8 +12114,10 @@ X86TargetLowering::EmitLoweredSelect(MachineInstr *MI, // If the EFLAGS register isn't dead in the terminator, then claim that it's // live into the sink and copy blocks. if (!MI->killsRegister(X86::EFLAGS)) { - copy0MBB->addLiveIn(X86::EFLAGS); - sinkMBB->addLiveIn(X86::EFLAGS); + if (!shouldHaveEFlagsKill(MI, BB)) { + copy0MBB->addLiveIn(X86::EFLAGS); + sinkMBB->addLiveIn(X86::EFLAGS); + } } // Transfer the remainder of BB and its successor edges to sinkMBB. diff --git a/test/CodeGen/X86/uint64-to-float.ll b/test/CodeGen/X86/uint64-to-float.ll index 1dbbdcf892..d9f753c7a8 100644 --- a/test/CodeGen/X86/uint64-to-float.ll +++ b/test/CodeGen/X86/uint64-to-float.ll @@ -6,37 +6,12 @@ target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64" target triple = "x86_64-apple-darwin10.0.0" -; FIXME: This test could generate this code: -; -; ## BB#0: ## %entry -; testq %rdi, %rdi -; jns LBB0_2 -; ## BB#1: -; movq %rdi, %rax -; shrq %rax -; andq $1, %rdi -; orq %rax, %rdi -; cvtsi2ssq %rdi, %xmm0 -; addss %xmm0, %xmm0 -; ret -; LBB0_2: ## %entry -; cvtsi2ssq %rdi, %xmm0 -; ret -; -; The blocks come from lowering: -; -; %vreg7<def> = CMOV_FR32 %vreg6<kill>, %vreg5<kill>, 15, %EFLAGS<imp-use>; FR32:%vreg7,%vreg6,%vreg5 -; -; If the instruction had an EFLAGS<kill> flag, it wouldn't need to mark EFLAGS -; as live-in on the new blocks, and machine sinking would be able to sink -; everything below the test. - -; CHECK: shrq -; CHECK: andq -; CHECK-NEXT: orq ; CHECK: testq %rdi, %rdi ; CHECK-NEXT: jns LBB0_2 -; CHECK: cvtsi2ss +; CHECK: shrq +; CHECK-NEXT: andq +; CHECK-NEXT: orq +; CHECK-NEXT: cvtsi2ss ; CHECK: LBB0_2 ; CHECK-NEXT: cvtsi2ss define float @test(i64 %a) { |