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Set EFLAGS correctly in EmitLoweredSelect on X86.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149597 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Lang Hames 2012-02-02 07:48:37 +00:00
parent d88710a3e0
commit 50a36f7102
2 changed files with 33 additions and 31 deletions
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31
lib/Target/X86/X86ISelLowering.cpp
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@ -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.

33
test/CodeGen/X86/uint64-to-float.ll
View File

@ -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) {