Teach VirtRegRewriter to handle spilling in instructions that have multiple

definitions of the virtual register.

This happens when spilling the registers produced by REG_SEQUENCE:

%reg1047:5<def>, %reg1047:6<def>, %reg1047:7<def> = VLD3d8 %reg1033, 0, pred:14, pred:%reg0

The rewriter would spill the register multiple times, dead store elimination
tried to keep up, but ended up cutting the branch it was sitting on.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104321 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-05-21 16:36:13 +00:00
parent 63e6a488cb
commit 2afb7505c5
2 changed files with 52 additions and 1 deletions

View File

@ -1895,6 +1895,11 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs,
// Clear kill info.
SmallSet<unsigned, 2> KilledMIRegs;
// Keep track of the registers we have already spilled in case there are
// multiple defs of the same register in MI.
SmallSet<unsigned, 8> SpilledMIRegs;
RegKills.reset();
KillOps.clear();
KillOps.resize(TRI->getNumRegs(), NULL);
@ -2412,6 +2417,7 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs,
}
// Process all of the spilled defs.
SpilledMIRegs.clear();
for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI.getOperand(i);
if (!(MO.isReg() && MO.getReg() && MO.isDef()))
@ -2505,7 +2511,7 @@ LocalRewriter::RewriteMBB(LiveIntervals *LIs,
MI.getOperand(i).setReg(RReg);
MI.getOperand(i).setSubReg(0);
if (!MO.isDead()) {
if (!MO.isDead() && SpilledMIRegs.insert(VirtReg)) {
MachineInstr *&LastStore = MaybeDeadStores[StackSlot];
SpillRegToStackSlot(MII, -1, PhysReg, StackSlot, RC, true,
LastStore, Spills, ReMatDefs, RegKills, KillOps);

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@ -0,0 +1,45 @@
; RUN: llc < %s -march=arm -mattr=+neon -O0
; This test would crash the rewriter when trying to handle a spill after one of
; the @llvm.arm.neon.vld3.v8i8 defined three parts of a register.
%struct.__neon_int8x8x3_t = type { <8 x i8>, <8 x i8>, <8 x i8> }
declare %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8*) nounwind readonly
declare void @llvm.arm.neon.vst3.v8i8(i8*, <8 x i8>, <8 x i8>, <8 x i8>) nounwind
define <8 x i8> @t3(i8* %A1, i8* %A2, i8* %A3, i8* %A4, i8* %A5, i8* %A6, i8* %A7, i8* %A8, i8* %B) nounwind {
%tmp1b = call %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8* %A2) ; <%struct.__neon_int8x8x3_t> [#uses=2]
%tmp2b = extractvalue %struct.__neon_int8x8x3_t %tmp1b, 0 ; <<8 x i8>> [#uses=1]
%tmp4b = extractvalue %struct.__neon_int8x8x3_t %tmp1b, 1 ; <<8 x i8>> [#uses=1]
%tmp1d = call %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8* %A4) ; <%struct.__neon_int8x8x3_t> [#uses=2]
%tmp2d = extractvalue %struct.__neon_int8x8x3_t %tmp1d, 0 ; <<8 x i8>> [#uses=1]
%tmp4d = extractvalue %struct.__neon_int8x8x3_t %tmp1d, 1 ; <<8 x i8>> [#uses=1]
%tmp1e = call %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8* %A5) ; <%struct.__neon_int8x8x3_t> [#uses=1]
%tmp2e = extractvalue %struct.__neon_int8x8x3_t %tmp1e, 0 ; <<8 x i8>> [#uses=1]
%tmp1f = call %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8* %A6) ; <%struct.__neon_int8x8x3_t> [#uses=1]
%tmp2f = extractvalue %struct.__neon_int8x8x3_t %tmp1f, 0 ; <<8 x i8>> [#uses=1]
%tmp1g = call %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8* %A7) ; <%struct.__neon_int8x8x3_t> [#uses=2]
%tmp2g = extractvalue %struct.__neon_int8x8x3_t %tmp1g, 0 ; <<8 x i8>> [#uses=1]
%tmp4g = extractvalue %struct.__neon_int8x8x3_t %tmp1g, 1 ; <<8 x i8>> [#uses=1]
%tmp1h = call %struct.__neon_int8x8x3_t @llvm.arm.neon.vld3.v8i8(i8* %A8) ; <%struct.__neon_int8x8x3_t> [#uses=2]
%tmp2h = extractvalue %struct.__neon_int8x8x3_t %tmp1h, 0 ; <<8 x i8>> [#uses=1]
%tmp3h = extractvalue %struct.__neon_int8x8x3_t %tmp1h, 2 ; <<8 x i8>> [#uses=1]
%tmp2bd = add <8 x i8> %tmp2b, %tmp2d ; <<8 x i8>> [#uses=1]
%tmp4bd = add <8 x i8> %tmp4b, %tmp4d ; <<8 x i8>> [#uses=1]
%tmp2abcd = mul <8 x i8> undef, %tmp2bd ; <<8 x i8>> [#uses=1]
%tmp4abcd = mul <8 x i8> undef, %tmp4bd ; <<8 x i8>> [#uses=2]
call void @llvm.arm.neon.vst3.v8i8(i8* %A1, <8 x i8> %tmp4abcd, <8 x i8> zeroinitializer, <8 x i8> %tmp2abcd)
%tmp2ef = sub <8 x i8> %tmp2e, %tmp2f ; <<8 x i8>> [#uses=1]
%tmp2gh = sub <8 x i8> %tmp2g, %tmp2h ; <<8 x i8>> [#uses=1]
%tmp3gh = sub <8 x i8> zeroinitializer, %tmp3h ; <<8 x i8>> [#uses=1]
%tmp4ef = sub <8 x i8> zeroinitializer, %tmp4g ; <<8 x i8>> [#uses=1]
%tmp2efgh = mul <8 x i8> %tmp2ef, %tmp2gh ; <<8 x i8>> [#uses=1]
%tmp3efgh = mul <8 x i8> undef, %tmp3gh ; <<8 x i8>> [#uses=1]
%tmp4efgh = mul <8 x i8> %tmp4ef, undef ; <<8 x i8>> [#uses=2]
call void @llvm.arm.neon.vst3.v8i8(i8* %A2, <8 x i8> %tmp4efgh, <8 x i8> %tmp3efgh, <8 x i8> %tmp2efgh)
%tmp4 = sub <8 x i8> %tmp4efgh, %tmp4abcd ; <<8 x i8>> [#uses=1]
tail call void @llvm.arm.neon.vst3.v8i8(i8* %B, <8 x i8> zeroinitializer, <8 x i8> undef, <8 x i8> undef)
ret <8 x i8> %tmp4
}