[llvm] r259895 - Some stackslots are allocated to vregs which have no real reference.
Wei Mi via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 5 10:14:24 PST 2016
Author: wmi
Date: Fri Feb 5 12:14:24 2016
New Revision: 259895
URL: http://llvm.org/viewvc/llvm-project?rev=259895&view=rev
Log:
Some stackslots are allocated to vregs which have no real reference.
LiveRangeEdit::eliminateDeadDef is used to remove dead define instructions
after rematerialization. To remove a VNI for a vreg from its LiveInterval,
LiveIntervals::removeVRegDefAt is used. However, after non-PHI VNIs are all
removed, PHI VNI are still left in the LiveInterval. Such unused vregs will
be kept in RegsToSpill[] at the end of InlineSpiller::reMaterializeAll and
spiller will allocate stackslot for them.
The fix is to get rid of unused reg by checking whether it has non-dbg
reference instead of whether it has non-empty interval.
Added:
llvm/trunk/test/CodeGen/X86/unused_stackslots.ll
Modified:
llvm/trunk/lib/CodeGen/InlineSpiller.cpp
Modified: llvm/trunk/lib/CodeGen/InlineSpiller.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/InlineSpiller.cpp?rev=259895&r1=259894&r2=259895&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/InlineSpiller.cpp (original)
+++ llvm/trunk/lib/CodeGen/InlineSpiller.cpp Fri Feb 5 12:14:24 2016
@@ -981,18 +981,20 @@ void InlineSpiller::reMaterializeAll() {
DEBUG(dbgs() << "Remat created " << DeadDefs.size() << " dead defs.\n");
Edit->eliminateDeadDefs(DeadDefs, RegsToSpill);
- // Get rid of deleted and empty intervals.
+ // LiveRangeEdit::eliminateDeadDef is used to remove dead define instructions
+ // after rematerialization. To remove a VNI for a vreg from its LiveInterval,
+ // LiveIntervals::removeVRegDefAt is used. However, after non-PHI VNIs are all
+ // removed, PHI VNI are still left in the LiveInterval.
+ // So to get rid of unused reg, we need to check whether it has non-dbg
+ // reference instead of whether it has non-empty interval.
unsigned ResultPos = 0;
for (unsigned Reg : RegsToSpill) {
- if (!LIS.hasInterval(Reg))
- continue;
-
- LiveInterval &LI = LIS.getInterval(Reg);
- if (LI.empty()) {
+ if (MRI.reg_nodbg_empty(Reg)) {
Edit->eraseVirtReg(Reg);
continue;
}
-
+ assert((LIS.hasInterval(Reg) && !LIS.getInterval(Reg).empty()) &&
+ "Reg with empty interval has reference");
RegsToSpill[ResultPos++] = Reg;
}
RegsToSpill.erase(RegsToSpill.begin() + ResultPos, RegsToSpill.end());
Added: llvm/trunk/test/CodeGen/X86/unused_stackslots.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/unused_stackslots.ll?rev=259895&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/unused_stackslots.ll (added)
+++ llvm/trunk/test/CodeGen/X86/unused_stackslots.ll Fri Feb 5 12:14:24 2016
@@ -0,0 +1,246 @@
+; PR26374: Check no stack slots are allocated for vregs which have no real reference.
+; RUN: llc < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.ImageParameters = type { i32, i32, [0 x [16 x i16]] }
+%struct.InputParameters = type { i32, i32 }
+
+ at c = common global %struct.ImageParameters* null, align 8
+ at a = common global i16** null, align 8
+ at d = common global [6 x i32] zeroinitializer, align 16
+ at b = common global %struct.InputParameters* null, align 8
+ at e = common global [4 x i32] zeroinitializer, align 16
+
+; It is not easy to check there is no unused holes in stack allocated for spills,
+; so simply check the size of stack allocated cannot exceed 350.
+; (408 is used before the fix for PR26374. 344 is used after the fix).
+;
+; CHECK-LABEL: @fn
+; CHECK: subq {{\$3[0-4][0-9]}}, %rsp
+
+; Function Attrs: nounwind uwtable
+define i32 @fn() #0 {
+entry:
+ %n = alloca [8 x [8 x i32]], align 16
+ %tmp = bitcast [8 x [8 x i32]]* %n to i8*
+ call void @llvm.lifetime.start(i64 256, i8* %tmp) #3
+ %tmp1 = bitcast [8 x [8 x i32]]* %n to i8*
+ %arraydecay.1 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 1, i64 0
+ %tmp2 = bitcast i32* %arraydecay.1 to i8*
+ %arraydecay.2 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 2, i64 0
+ %tmp3 = bitcast i32* %arraydecay.2 to i8*
+ %arraydecay.3 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 3, i64 0
+ %tmp4 = bitcast i32* %arraydecay.3 to i8*
+ %arraydecay.4 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 4, i64 0
+ %tmp5 = bitcast i32* %arraydecay.4 to i8*
+ %arraydecay.5 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 5, i64 0
+ %tmp6 = bitcast i32* %arraydecay.5 to i8*
+ %arraydecay.6 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 6, i64 0
+ %tmp7 = bitcast i32* %arraydecay.6 to i8*
+ %arraydecay.7 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 7, i64 0
+ %tmp8 = bitcast i32* %arraydecay.7 to i8*
+ br label %for.body
+
+for.body: ; preds = %for.inc73, %entry
+ %q.0131 = phi i32 [ 0, %entry ], [ %inc74, %for.inc73 ]
+ %m.0130 = phi i32 [ 0, %entry ], [ %m.4, %for.inc73 ]
+ %div = sdiv i32 %q.0131, 2
+ %shl = shl i32 %div, 3
+ %rem = srem i32 %q.0131, 2
+ %shl1 = shl nsw i32 %rem, 3
+ %tmp9 = sext i32 %shl1 to i64
+ %tmp10 = sext i32 %shl to i64
+ %tmp11 = or i32 %shl1, 4
+ %tmp12 = sext i32 %tmp11 to i64
+ %tmp13 = or i32 %shl, 4
+ %tmp14 = sext i32 %tmp13 to i64
+ br label %for.body4
+
+for.body4: ; preds = %for.inc48, %for.body
+ %indvars.iv148 = phi i64 [ %tmp10, %for.body ], [ %indvars.iv.next149, %for.inc48 ]
+ %m.1126 = phi i32 [ %m.0130, %for.body ], [ %m.3.lcssa, %for.inc48 ]
+ %tmp15 = load %struct.ImageParameters*, %struct.ImageParameters** @c, align 8
+ %opix_y = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %tmp15, i64 0, i32 1
+ %tmp16 = load i32, i32* %opix_y, align 4
+ %tmp17 = trunc i64 %indvars.iv148 to i32
+ %add5 = add nsw i32 %tmp16, %tmp17
+ %tmp18 = sub nuw nsw i64 %indvars.iv148, %tmp10
+ %tmp19 = sext i32 %add5 to i64
+ %tmp20 = add nsw i64 %tmp19, 1
+ %tmp21 = or i64 %indvars.iv148, 1
+ %tmp22 = or i64 %tmp18, 1
+ %tmp23 = add nsw i64 %tmp19, 2
+ %tmp24 = or i64 %indvars.iv148, 2
+ %tmp25 = or i64 %tmp18, 2
+ %tmp26 = add nsw i64 %tmp19, 3
+ %tmp27 = or i64 %indvars.iv148, 3
+ %tmp28 = or i64 %tmp18, 3
+ br label %for.body9
+
+for.body9: ; preds = %for.inc45.for.body9_crit_edge, %for.body4
+ %tmp29 = phi %struct.ImageParameters* [ %tmp15, %for.body4 ], [ %.pre, %for.inc45.for.body9_crit_edge ]
+ %indvars.iv145 = phi i64 [ %tmp9, %for.body4 ], [ %indvars.iv.next146, %for.inc45.for.body9_crit_edge ]
+ %m.2124 = phi i32 [ %m.1126, %for.body4 ], [ %m.3, %for.inc45.for.body9_crit_edge ]
+ %opix_x = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %tmp29, i64 0, i32 0
+ %tmp30 = load i32, i32* %opix_x, align 4
+ %tmp31 = trunc i64 %indvars.iv145 to i32
+ %add10 = add nsw i32 %tmp30, %tmp31
+ tail call void @LumaPrediction4x4(i32 %tmp31, i32 %tmp17, i32 0, i32 0, i32 0, i16 signext 0, i16 signext 0) #3
+ %tmp32 = load i16**, i16*** @a, align 8
+ %tmp33 = load %struct.ImageParameters*, %struct.ImageParameters** @c, align 8
+ %tmp34 = sub nuw nsw i64 %indvars.iv145, %tmp9
+ %tmp35 = sext i32 %add10 to i64
+ br label %for.cond14.preheader
+
+for.cond14.preheader: ; preds = %for.body9
+ %arrayidx = getelementptr inbounds i16*, i16** %tmp32, i64 %tmp19
+ %tmp36 = load i16*, i16** %arrayidx, align 8
+ %arrayidx20 = getelementptr inbounds i16, i16* %tmp36, i64 %tmp35
+ %arrayidx26 = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %tmp33, i64 0, i32 2, i64 %indvars.iv148, i64 %indvars.iv145
+ %arrayidx35 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 %tmp18, i64 %tmp34
+ %tmp37 = bitcast i16* %arrayidx20 to <4 x i16>*
+ %tmp38 = load <4 x i16>, <4 x i16>* %tmp37, align 2
+ %tmp39 = zext <4 x i16> %tmp38 to <4 x i32>
+ %tmp40 = bitcast i16* %arrayidx26 to <4 x i16>*
+ %tmp41 = load <4 x i16>, <4 x i16>* %tmp40, align 2
+ %tmp42 = zext <4 x i16> %tmp41 to <4 x i32>
+ %tmp43 = sub nsw <4 x i32> %tmp39, %tmp42
+ %tmp44 = bitcast i32* %arrayidx35 to <4 x i32>*
+ store <4 x i32> %tmp43, <4 x i32>* %tmp44, align 16
+ store <4 x i32> %tmp43, <4 x i32>* bitcast ([6 x i32]* @d to <4 x i32>*), align 16
+ %arrayidx.1 = getelementptr inbounds i16*, i16** %tmp32, i64 %tmp20
+ %tmp45 = load i16*, i16** %arrayidx.1, align 8
+ %arrayidx20.1 = getelementptr inbounds i16, i16* %tmp45, i64 %tmp35
+ %arrayidx26.1 = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %tmp33, i64 0, i32 2, i64 %tmp21, i64 %indvars.iv145
+ %arrayidx35.1 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 %tmp22, i64 %tmp34
+ %tmp46 = bitcast i16* %arrayidx20.1 to <4 x i16>*
+ %tmp47 = load <4 x i16>, <4 x i16>* %tmp46, align 2
+ %tmp48 = zext <4 x i16> %tmp47 to <4 x i32>
+ %tmp49 = bitcast i16* %arrayidx26.1 to <4 x i16>*
+ %tmp50 = load <4 x i16>, <4 x i16>* %tmp49, align 2
+ %tmp51 = zext <4 x i16> %tmp50 to <4 x i32>
+ %tmp52 = sub nsw <4 x i32> %tmp48, %tmp51
+ %tmp53 = bitcast i32* %arrayidx35.1 to <4 x i32>*
+ store <4 x i32> %tmp52, <4 x i32>* %tmp53, align 16
+ store <4 x i32> %tmp52, <4 x i32>* bitcast (i32* getelementptr inbounds ([6 x i32], [6 x i32]* @d, i64 0, i64 4) to <4 x i32>*), align 16
+ %arrayidx.2 = getelementptr inbounds i16*, i16** %tmp32, i64 %tmp23
+ %tmp54 = load i16*, i16** %arrayidx.2, align 8
+ %arrayidx20.2 = getelementptr inbounds i16, i16* %tmp54, i64 %tmp35
+ %arrayidx26.2 = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %tmp33, i64 0, i32 2, i64 %tmp24, i64 %indvars.iv145
+ %arrayidx35.2 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 %tmp25, i64 %tmp34
+ %tmp55 = bitcast i16* %arrayidx20.2 to <4 x i16>*
+ %tmp56 = load <4 x i16>, <4 x i16>* %tmp55, align 2
+ %tmp57 = zext <4 x i16> %tmp56 to <4 x i32>
+ %tmp58 = bitcast i16* %arrayidx26.2 to <4 x i16>*
+ %tmp59 = load <4 x i16>, <4 x i16>* %tmp58, align 2
+ %tmp60 = zext <4 x i16> %tmp59 to <4 x i32>
+ %tmp61 = sub nsw <4 x i32> %tmp57, %tmp60
+ %tmp62 = bitcast i32* %arrayidx35.2 to <4 x i32>*
+ store <4 x i32> %tmp61, <4 x i32>* %tmp62, align 16
+ store <4 x i32> %tmp61, <4 x i32>* bitcast (i32* getelementptr ([6 x i32], [6 x i32]* @d, i64 1, i64 2) to <4 x i32>*), align 16
+ %arrayidx.3 = getelementptr inbounds i16*, i16** %tmp32, i64 %tmp26
+ %tmp63 = load i16*, i16** %arrayidx.3, align 8
+ %arrayidx20.3 = getelementptr inbounds i16, i16* %tmp63, i64 %tmp35
+ %arrayidx26.3 = getelementptr inbounds %struct.ImageParameters, %struct.ImageParameters* %tmp33, i64 0, i32 2, i64 %tmp27, i64 %indvars.iv145
+ %arrayidx35.3 = getelementptr inbounds [8 x [8 x i32]], [8 x [8 x i32]]* %n, i64 0, i64 %tmp28, i64 %tmp34
+ %tmp64 = bitcast i16* %arrayidx20.3 to <4 x i16>*
+ %tmp65 = load <4 x i16>, <4 x i16>* %tmp64, align 2
+ %tmp66 = zext <4 x i16> %tmp65 to <4 x i32>
+ %tmp67 = bitcast i16* %arrayidx26.3 to <4 x i16>*
+ %tmp68 = load <4 x i16>, <4 x i16>* %tmp67, align 2
+ %tmp69 = zext <4 x i16> %tmp68 to <4 x i32>
+ %tmp70 = sub nsw <4 x i32> %tmp66, %tmp69
+ %tmp71 = bitcast i32* %arrayidx35.3 to <4 x i32>*
+ store <4 x i32> %tmp70, <4 x i32>* %tmp71, align 16
+ store <4 x i32> %tmp70, <4 x i32>* bitcast (i32* getelementptr ([6 x i32], [6 x i32]* @d, i64 2, i64 0) to <4 x i32>*), align 16
+ %tmp72 = load %struct.InputParameters*, %struct.InputParameters** @b, align 8
+ %rdopt = getelementptr inbounds %struct.InputParameters, %struct.InputParameters* %tmp72, i64 0, i32 0
+ %tmp73 = load i32, i32* %rdopt, align 4
+ %cmp42 = icmp eq i32 %tmp73, 0
+ br i1 %cmp42, label %land.lhs.true, label %if.then
+
+land.lhs.true: ; preds = %for.cond14.preheader
+ %Transform8x8Mode = getelementptr inbounds %struct.InputParameters, %struct.InputParameters* %tmp72, i64 0, i32 1
+ %tmp74 = load i32, i32* %Transform8x8Mode, align 4
+ %tobool = icmp eq i32 %tmp74, 0
+ br i1 %tobool, label %if.then, label %for.inc45
+
+if.then: ; preds = %land.lhs.true, %for.cond14.preheader
+ %call = tail call i32 @distortion4x4(i32* nonnull getelementptr inbounds ([6 x i32], [6 x i32]* @d, i64 0, i64 0)) #3
+ %add44 = add nsw i32 %call, %m.2124
+ br label %for.inc45
+
+for.inc45: ; preds = %if.then, %land.lhs.true
+ %m.3 = phi i32 [ %m.2124, %land.lhs.true ], [ %add44, %if.then ]
+ %cmp8 = icmp slt i64 %indvars.iv145, %tmp12
+ br i1 %cmp8, label %for.inc45.for.body9_crit_edge, label %for.inc48
+
+for.inc45.for.body9_crit_edge: ; preds = %for.inc45
+ %indvars.iv.next146 = add nsw i64 %indvars.iv145, 4
+ %.pre = load %struct.ImageParameters*, %struct.ImageParameters** @c, align 8
+ br label %for.body9
+
+for.inc48: ; preds = %for.inc45
+ %m.3.lcssa = phi i32 [ %m.3, %for.inc45 ]
+ %indvars.iv.next149 = add nsw i64 %indvars.iv148, 4
+ %cmp3 = icmp slt i64 %indvars.iv148, %tmp14
+ br i1 %cmp3, label %for.body4, label %for.end50
+
+for.end50: ; preds = %for.inc48
+ %m.3.lcssa.lcssa = phi i32 [ %m.3.lcssa, %for.inc48 ]
+ %tmp75 = load %struct.InputParameters*, %struct.InputParameters** @b, align 8
+ %rdopt51 = getelementptr inbounds %struct.InputParameters, %struct.InputParameters* %tmp75, i64 0, i32 0
+ %tmp76 = load i32, i32* %rdopt51, align 4
+ %cmp52 = icmp eq i32 %tmp76, 0
+ br i1 %cmp52, label %land.lhs.true54, label %for.inc73
+
+land.lhs.true54: ; preds = %for.end50
+ %Transform8x8Mode55 = getelementptr inbounds %struct.InputParameters, %struct.InputParameters* %tmp75, i64 0, i32 1
+ %tmp77 = load i32, i32* %Transform8x8Mode55, align 4
+ %tobool56 = icmp eq i32 %tmp77, 0
+ br i1 %tobool56, label %for.inc73, label %for.body61.preheader
+
+for.body61.preheader: ; preds = %land.lhs.true54
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 4, i64 0) to i8*), i8* %tmp1, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 6, i64 0) to i8*), i8* %tmp2, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 8, i64 0) to i8*), i8* %tmp3, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 10, i64 0) to i8*), i8* %tmp4, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 12, i64 0) to i8*), i8* %tmp5, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 14, i64 0) to i8*), i8* %tmp6, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 16, i64 0) to i8*), i8* %tmp7, i64 32, i32 16, i1 false)
+ call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull bitcast (i32* getelementptr ([4 x i32], [4 x i32]* @e, i64 18, i64 0) to i8*), i8* %tmp8, i64 32, i32 16, i1 false)
+ %call70 = tail call i32 @distortion4x4(i32* nonnull getelementptr inbounds ([4 x i32], [4 x i32]* @e, i64 0, i64 0)) #3
+ %add71 = add nsw i32 %call70, %m.3.lcssa.lcssa
+ br label %for.inc73
+
+for.inc73: ; preds = %for.body61.preheader, %land.lhs.true54, %for.end50
+ %m.4 = phi i32 [ %add71, %for.body61.preheader ], [ %m.3.lcssa.lcssa, %land.lhs.true54 ], [ %m.3.lcssa.lcssa, %for.end50 ]
+ %inc74 = add nuw nsw i32 %q.0131, 1
+ %exitcond156 = icmp eq i32 %inc74, 4
+ br i1 %exitcond156, label %for.end75, label %for.body
+
+for.end75: ; preds = %for.inc73
+ %m.4.lcssa = phi i32 [ %m.4, %for.inc73 ]
+ call void @llvm.lifetime.end(i64 256, i8* %tmp) #3
+ ret i32 %m.4.lcssa
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start(i64, i8* nocapture) #1
+
+declare void @LumaPrediction4x4(i32, i32, i32, i32, i32, i16 signext, i16 signext) #2
+
+declare i32 @distortion4x4(i32*) #2
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) #1
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture) #1
+
+attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { argmemonly nounwind }
+attributes #2 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #3 = { nounwind }
+
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