[llvm] r238785 - LiveRangeEdit: Fix liveranges not shrinking on subrange kill.
Matthias Braun
matze at braunis.de
Mon Jun 1 14:26:27 PDT 2015
Author: matze
Date: Mon Jun 1 16:26:26 2015
New Revision: 238785
URL: http://llvm.org/viewvc/llvm-project?rev=238785&view=rev
Log:
LiveRangeEdit: Fix liveranges not shrinking on subrange kill.
If a dead instruction we may not only have a last-use in the main live
range but also in a subregister range if subregisters are tracked. We
need to partially rebuild live ranges in both cases.
The testcase only broke when subregister liveness was enabled. I
commited it in the current form because there is currently no flag to
enable/disable subregister liveness.
This fixes PR23720.
Added:
llvm/trunk/test/CodeGen/R600/subreg-eliminate-dead.ll
Modified:
llvm/trunk/include/llvm/CodeGen/LiveRangeEdit.h
llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
Modified: llvm/trunk/include/llvm/CodeGen/LiveRangeEdit.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/LiveRangeEdit.h?rev=238785&r1=238784&r2=238785&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/LiveRangeEdit.h (original)
+++ llvm/trunk/include/llvm/CodeGen/LiveRangeEdit.h Mon Jun 1 16:26:26 2015
@@ -102,6 +102,10 @@ private:
/// registers are created.
void MRI_NoteNewVirtualRegister(unsigned VReg) override;
+ /// \brief Check if MachineOperand \p MO is a last use/kill either in the
+ /// main live range of \p LI or in one of the matching subregister ranges.
+ bool useIsKill(const LiveInterval &LI, const MachineOperand &MO) const;
+
public:
/// Create a LiveRangeEdit for breaking down parent into smaller pieces.
/// @param parent The register being spilled or split.
Modified: llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp?rev=238785&r1=238784&r2=238785&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveRangeEdit.cpp Mon Jun 1 16:26:26 2015
@@ -218,6 +218,22 @@ bool LiveRangeEdit::foldAsLoad(LiveInter
return true;
}
+bool LiveRangeEdit::useIsKill(const LiveInterval &LI,
+ const MachineOperand &MO) const {
+ const MachineInstr *MI = MO.getParent();
+ SlotIndex Idx = LIS.getInstructionIndex(MI).getRegSlot();
+ if (LI.Query(Idx).isKill())
+ return true;
+ const TargetRegisterInfo &TRI = *MRI.getTargetRegisterInfo();
+ unsigned SubReg = MO.getSubReg();
+ unsigned LaneMask = TRI.getSubRegIndexLaneMask(SubReg);
+ for (const LiveInterval::SubRange &S : LI.subranges()) {
+ if ((S.LaneMask & LaneMask) != 0 && S.Query(Idx).isKill())
+ return true;
+ }
+ return false;
+}
+
/// Find all live intervals that need to shrink, then remove the instruction.
void LiveRangeEdit::eliminateDeadDef(MachineInstr *MI, ToShrinkSet &ToShrink) {
assert(MI->allDefsAreDead() && "Def isn't really dead");
@@ -266,9 +282,8 @@ void LiveRangeEdit::eliminateDeadDef(Mac
// unlikely to change anything. We typically don't want to shrink the
// PIC base register that has lots of uses everywhere.
// Always shrink COPY uses that probably come from live range splitting.
- if (MI->readsVirtualRegister(Reg) &&
- (MI->isCopy() || MOI->isDef() || MRI.hasOneNonDBGUse(Reg) ||
- LI.Query(Idx).isKill()))
+ if ((MI->readsVirtualRegister(Reg) && (MI->isCopy() || MOI->isDef())) ||
+ (MOI->readsReg() && (MRI.hasOneNonDBGUse(Reg) || useIsKill(LI, *MOI))))
ToShrink.insert(&LI);
// Remove defined value.
Added: llvm/trunk/test/CodeGen/R600/subreg-eliminate-dead.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/R600/subreg-eliminate-dead.ll?rev=238785&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/R600/subreg-eliminate-dead.ll (added)
+++ llvm/trunk/test/CodeGen/R600/subreg-eliminate-dead.ll Mon Jun 1 16:26:26 2015
@@ -0,0 +1,55 @@
+; RUN: llc -verify-machineinstrs -o - %s | FileCheck %s
+; LiveRangeEdit::eliminateDeadDef did not update LiveInterval sub ranges
+; properly.
+target datalayout = "e-p:32:32-p1:64:64-p2:64:64-p3:32:32-p4:64:64-p5:32:32-p24:64:64-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64"
+target triple = "amdgcn--"
+
+; CHECK-LABEL: foobar:
+; Output with subregister liveness disabled:
+; CHECK: v_mov_b32_e32 v1, 1
+; CHECK: v_mov_b32_e32 v0, 0
+; CHECK: v_cmp_eq_i32_e32 vcc, s0, v0
+; CHECK: v_cmp_eq_i32_e64 s[0:1], s0, v1
+; CHECK: v_mov_b32_e32 v1, 3
+; CHECK: v_mov_b32_e32 v0, 2
+; CHECK: v_cmp_eq_i32_e64 s[2:3], s0, v0
+; CHECK: v_cmp_eq_i32_e64 s[4:5], s0, v1
+; CHECK: v_cndmask_b32_e64 v3, 0, -1, s[4:5]
+; CHECK: v_cndmask_b32_e64 v2, 0, -1, s[2:3]
+; CHECK: v_cndmask_b32_e64 v1, 0, -1, s[0:1]
+; CHECK: v_cndmask_b32_e64 v0, 0, -1, vcc
+; CHECK: v_cmp_ne_i32_e32 vcc, 0, v1
+; CHECK: v_cndmask_b32_e64 v1, 0, v0, vcc
+; CHECK: s_mov_b32 s3, 0xf000
+; CHECK: s_mov_b32 s2, -1
+; CHECK: buffer_store_dwordx2 v[0:1], s[0:3], 0
+; CHECK: s_endpgm
+; Output with subregister liveness enabled:
+; XCHECK: v_mov_b32_e32 v1, 1
+; XCHECK: v_mov_b32_e32 v0, 0
+; XCHECK: v_cmp_eq_i32_e32 vcc, s0, v1
+; XCHECK: v_mov_b32_e32 v1, 3
+; XCHECK: v_mov_b32_e32 v0, 2
+; XCHECK: v_cmp_eq_i32_e64 s[0:1], s0, v0
+; XCHECK: v_cmp_eq_i32_e64 s[2:3], s0, v1
+; XCHECK: v_cndmask_b32_e64 v3, 0, -1, s[2:3]
+; XCHECK: v_cndmask_b32_e64 v2, 0, -1, s[0:1]
+; XCHECK: v_cndmask_b32_e64 v1, 0, -1, vcc
+; XCHECK: v_cmp_ne_i32_e32 vcc, 0, v1
+; XCHECK: v_cndmask_b32_e64 v1, 0, v0, vcc
+; XCHECK: s_mov_b32 s3, 0xf000
+; XCHECK: s_mov_b32 s2, -1
+; XCHECK: buffer_store_dwordx2 v[0:1], s[0:3], 0
+; XCHECK: s_endpgm
+define void @foobar() {
+ %v0 = icmp eq <4 x i32> undef, <i32 0, i32 1, i32 2, i32 3>
+ %v3 = sext <4 x i1> %v0 to <4 x i32>
+ %v4 = extractelement <4 x i32> %v3, i32 1
+ %v5 = icmp ne i32 %v4, 0
+ %v6 = select i1 %v5, i32 undef, i32 0
+ %v15 = insertelement <2 x i32> undef, i32 %v6, i32 1
+ store <2 x i32> %v15, <2 x i32> addrspace(1)* undef, align 8
+ ret void
+}
+
+declare double @llvm.fma.f64(double, double, double)
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