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Make sure to add kill flags to the last use of a virtreg when it is redefined.

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The X86 floating point stack pass and others depend on good kill flags.

llvm-svn: 103635
This commit is contained in:
Jakob Stoklund Olesen 2010-05-12 18:46:03 +00:00
parent 2c350fe8a7
commit 7d1323d9a5
2 changed files with 81 additions and 12 deletions
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34
lib/CodeGen/RegAllocFast.cpp
View File

@ -121,8 +121,9 @@ namespace {
bool runOnMachineFunction(MachineFunction &Fn);
void AllocateBasicBlock(MachineBasicBlock &MBB);
int getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC);
void killVirtReg(unsigned VirtReg);
void addKillFlag(LiveRegMap::iterator i);
void killVirtReg(LiveRegMap::iterator i);
void killVirtReg(unsigned VirtReg);
void spillVirtReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
unsigned VirtReg, bool isKill);
void killPhysReg(unsigned PhysReg);
@ -161,20 +162,27 @@ int RAFast::getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC) {
return FrameIdx;
}
/// killVirtReg - Mark virtreg as no longer available.
void RAFast::killVirtReg(LiveRegMap::iterator i) {
assert(i != LiveVirtRegs.end() && "Killing unmapped virtual register");
unsigned VirtReg = i->first;
const LiveReg &LR = i->second;
assert(PhysRegState[LR.PhysReg] == VirtReg && "Broken RegState mapping");
PhysRegState[LR.PhysReg] = regFree;
/// addKillFlag - Set kill flags on last use of a virtual register.
void RAFast::addKillFlag(LiveRegMap::iterator lri) {
assert(lri != LiveVirtRegs.end() && "Killing unmapped virtual register");
const LiveReg &LR = lri->second;
if (LR.LastUse) {
MachineOperand &MO = LR.LastUse->getOperand(LR.LastOpNum);
if (MO.isUse()) MO.setIsKill();
else MO.setIsDead();
DEBUG(dbgs() << " - last seen here: " << *LR.LastUse);
if (MO.isDef())
MO.setIsDead();
else if (!LR.LastUse->isRegTiedToDefOperand(LR.LastOpNum))
MO.setIsKill();
DEBUG(dbgs() << " %reg" << lri->first << " killed: " << *LR.LastUse);
}
LiveVirtRegs.erase(i);
}
/// killVirtReg - Mark virtreg as no longer available.
void RAFast::killVirtReg(LiveRegMap::iterator lri) {
addKillFlag(lri);
const LiveReg &LR = lri->second;
assert(PhysRegState[LR.PhysReg] == lri->first && "Broken RegState mapping");
PhysRegState[LR.PhysReg] = regFree;
LiveVirtRegs.erase(lri);
}
/// killVirtReg - Mark virtreg as no longer available.
@ -445,6 +453,8 @@ unsigned RAFast::defineVirtReg(MachineBasicBlock &MBB, MachineInstr *MI,
LiveRegMap::iterator lri = LiveVirtRegs.find(VirtReg);
if (lri == LiveVirtRegs.end())
lri = allocVirtReg(MBB, MI, VirtReg);
else
addKillFlag(lri); // Kill before redefine.
LiveReg &LR = lri->second;
LR.LastUse = MI;
LR.LastOpNum = OpNum;

59
test/CodeGen/X86/2010-05-12-FastAllocKills.ll Normal file
View File

@ -0,0 +1,59 @@
; RUN: llc -regalloc=fast -verify-machineinstrs < %s
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-darwin"
; This test causes a virtual FP register to be redefined while it is live:
;BB#5: derived from LLVM BB %bb10
; Predecessors according to CFG: BB#4 BB#5
; %reg1024<def> = MOV_Fp8080 %reg1034
; %reg1025<def> = MUL_Fp80m32 %reg1024, %RIP, 1, %reg0, <cp#0>, %reg0; mem:LD4[ConstantPool]
; %reg1034<def> = MOV_Fp8080 %reg1025
; FP_REG_KILL %FP0<imp-def>, %FP1<imp-def>, %FP2<imp-def>, %FP3<imp-def>, %FP4<imp-def>, %FP5<imp-def>, %FP6<imp-def>
; JMP_4 <BB#5>
; Successors according to CFG: BB#5
;
; The X86FP pass needs good kill flags, like on %FP0 representing %reg1034:
;BB#5: derived from LLVM BB %bb10
; Predecessors according to CFG: BB#4 BB#5
; %FP0<def> = LD_Fp80m <fi#3>, 1, %reg0, 0, %reg0; mem:LD10[FixedStack3](align=4)
; %FP1<def> = MOV_Fp8080 %FP0<kill>
; %FP2<def> = MUL_Fp80m32 %FP1, %RIP, 1, %reg0, <cp#0>, %reg0; mem:LD4[ConstantPool]
; %FP0<def> = MOV_Fp8080 %FP2
; ST_FpP80m <fi#3>, 1, %reg0, 0, %reg0, %FP0<kill>; mem:ST10[FixedStack3](align=4)
; ST_FpP80m <fi#4>, 1, %reg0, 0, %reg0, %FP1<kill>; mem:ST10[FixedStack4](align=4)
; ST_FpP80m <fi#5>, 1, %reg0, 0, %reg0, %FP2<kill>; mem:ST10[FixedStack5](align=4)
; FP_REG_KILL %FP0<imp-def>, %FP1<imp-def>, %FP2<imp-def>, %FP3<imp-def>, %FP4<imp-def>, %FP5<imp-def>, %FP6<imp-def>
; JMP_4 <BB#5>
; Successors according to CFG: BB#5
define fastcc i32 @sqlite3AtoF(i8* %z, double* nocapture %pResult) nounwind ssp {
entry:
br i1 undef, label %bb2, label %bb1.i.i
bb1.i.i: ; preds = %entry
unreachable
bb2: ; preds = %entry
br i1 undef, label %isdigit339.exit11.preheader, label %bb13
isdigit339.exit11.preheader: ; preds = %bb2
br i1 undef, label %bb12, label %bb10
bb10: ; preds = %bb10, %isdigit339.exit11.preheader
%divisor.041 = phi x86_fp80 [ %0, %bb10 ], [ 0xK3FFF8000000000000000, %isdigit339.exit11.preheader ] ; <x86_fp80> [#uses=1]
%0 = fmul x86_fp80 %divisor.041, 0xK4002A000000000000000 ; <x86_fp80> [#uses=2]
br i1 false, label %bb12, label %bb10
bb12: ; preds = %bb10, %isdigit339.exit11.preheader
%divisor.0.lcssa = phi x86_fp80 [ 0xK3FFF8000000000000000, %isdigit339.exit11.preheader ], [ %0, %bb10 ] ; <x86_fp80> [#uses=0]
br label %bb13
bb13: ; preds = %bb12, %bb2
br i1 undef, label %bb34, label %bb36
bb34: ; preds = %bb13
br label %bb36
bb36: ; preds = %bb34, %bb13
ret i32 undef
}