// Value in the other live range that overlaps this def, if any.
VNInfo *OtherVNI;
- // Is this value an IMPLICIT_DEF?
- bool IsImplicitDef;
+ // Is this value an IMPLICIT_DEF that can be erased?
+ //
+ // IMPLICIT_DEF values should only exist at the end of a basic block that
+ // is a predecessor to a phi-value. These IMPLICIT_DEF instructions can be
+ // safely erased if they are overlapping a live value in the other live
+ // interval.
+ //
+ // Weird control flow graphs and incomplete PHI handling in
+ // ProcessImplicitDefs can very rarely create IMPLICIT_DEF values with
+ // longer live ranges. Such IMPLICIT_DEF values should be treated like
+ // normal values.
+ bool ErasableImplicitDef;
// True when the live range of this value will be pruned because of an
// overlapping CR_Replace value in the other live range.
bool PrunedComputed;
Val() : Resolution(CR_Keep), WriteLanes(0), ValidLanes(0),
- RedefVNI(0), OtherVNI(0), IsImplicitDef(false), Pruned(false),
- PrunedComputed(false) {}
+ RedefVNI(0), OtherVNI(0), ErasableImplicitDef(false),
+ Pruned(false), PrunedComputed(false) {}
bool isAnalyzed() const { return WriteLanes != 0; }
};
// An IMPLICIT_DEF writes undef values.
if (DefMI->isImplicitDef()) {
- V.IsImplicitDef = true;
+ // We normally expect IMPLICIT_DEF values to be live only until the end
+ // of their block. If the value is really live longer and gets pruned in
+ // another block, this flag is cleared again.
+ V.ErasableImplicitDef = true;
V.ValidLanes &= ~V.WriteLanes;
}
}
// We have overlapping values, or possibly a kill of Other.
// Recursively compute assignments up the dominator tree.
Other.computeAssignment(V.OtherVNI->id, *this);
- const Val &OtherV = Other.Vals[V.OtherVNI->id];
+ Val &OtherV = Other.Vals[V.OtherVNI->id];
+
+ // Check if OtherV is an IMPLICIT_DEF that extends beyond its basic block.
+ // This shouldn't normally happen, but ProcessImplicitDefs can leave such
+ // IMPLICIT_DEF instructions behind, and there is nothing wrong with it
+ // technically.
+ //
+ // WHen it happens, treat that IMPLICIT_DEF as a normal value, and don't try
+ // to erase the IMPLICIT_DEF instruction.
+ if (OtherV.ErasableImplicitDef && DefMI &&
+ DefMI->getParent() != Indexes->getMBBFromIndex(V.OtherVNI->def)) {
+ DEBUG(dbgs() << "IMPLICIT_DEF defined at " << V.OtherVNI->def
+ << " extends into BB#" << DefMI->getParent()->getNumber()
+ << ", keeping it.\n");
+ OtherV.ErasableImplicitDef = false;
+ }
// Allow overlapping PHI values. Any real interference would show up in a
// predecessor, the PHI itself can't introduce any conflicts.
// predecessors, so the instruction should simply go away once its value
// has been replaced.
Val &OtherV = Other.Vals[Vals[i].OtherVNI->id];
- bool EraseImpDef = OtherV.IsImplicitDef && OtherV.Resolution == CR_Keep;
+ bool EraseImpDef = OtherV.ErasableImplicitDef &&
+ OtherV.Resolution == CR_Keep;
if (!Def.isBlock()) {
// Remove <def,read-undef> flags. This def is now a partial redef.
// Also remove <def,dead> flags since the joined live range will
// If an IMPLICIT_DEF value is pruned, it doesn't serve a purpose any
// longer. The IMPLICIT_DEF instructions are only inserted by
// PHIElimination to guarantee that all PHI predecessors have a value.
- if (!Vals[i].IsImplicitDef || !Vals[i].Pruned)
+ if (!Vals[i].ErasableImplicitDef || !Vals[i].Pruned)
break;
// Remove value number i from LI. Note that this VNInfo is still present
// in NewVNInfo, so it will appear as an unused value number in the final
--- /dev/null
+; RUN: llc < %s -verify-coalescing
+; PR14732
+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-S128"
+target triple = "x86_64-apple-macosx10"
+
+@c = common global i32 0, align 4
+@b = common global i32 0, align 4
+@a = common global i32 0, align 4
+@d = common global i32 0, align 4
+
+; This function creates an IMPLICIT_DEF with a long live range, even after
+; ProcessImplicitDefs.
+;
+; The coalescer should be able to deal with all kinds of IMPLICIT_DEF live
+; ranges, even if they are not common.
+
+define void @f() nounwind uwtable ssp {
+entry:
+ %i = alloca i32, align 4
+ br label %for.cond
+
+for.cond: ; preds = %for.inc34, %entry
+ %i.0.load44 = phi i32 [ %inc35, %for.inc34 ], [ undef, %entry ]
+ %pi.0 = phi i32* [ %pi.4, %for.inc34 ], [ undef, %entry ]
+ %tobool = icmp eq i32 %i.0.load44, 0
+ br i1 %tobool, label %for.end36, label %for.body
+
+for.body: ; preds = %for.cond
+ store i32 0, i32* @c, align 4, !tbaa !0
+ br label %for.body2
+
+for.body2: ; preds = %for.body, %for.inc
+ %i.0.load45 = phi i32 [ %i.0.load44, %for.body ], [ 0, %for.inc ]
+ %tobool3 = icmp eq i32 %i.0.load45, 0
+ br i1 %tobool3, label %if.then10, label %if.then
+
+if.then: ; preds = %for.body2
+ store i32 0, i32* %i, align 4, !tbaa !0
+ br label %for.body6
+
+for.body6: ; preds = %if.then, %for.body6
+ store i32 0, i32* %i, align 4
+ br i1 true, label %for.body6, label %for.inc
+
+if.then10: ; preds = %for.body2
+ store i32 1, i32* @b, align 4, !tbaa !0
+ ret void
+
+for.inc: ; preds = %for.body6
+ br i1 undef, label %for.body2, label %if.end30
+
+while.condthread-pre-split: ; preds = %label.loopexit, %while.condthread-pre-split.lr.ph.lr.ph, %for.inc27.backedge
+ %0 = phi i32 [ %inc28, %for.inc27.backedge ], [ %inc285863, %while.condthread-pre-split.lr.ph.lr.ph ], [ %inc2858, %label.loopexit ]
+ %inc2060 = phi i32 [ %inc20, %for.inc27.backedge ], [ %a.promoted.pre, %while.condthread-pre-split.lr.ph.lr.ph ], [ %inc20, %label.loopexit ]
+ br label %while.cond
+
+while.cond: ; preds = %while.condthread-pre-split, %while.cond
+ %p2.1.in = phi i32* [ %pi.3.ph, %while.cond ], [ %i, %while.condthread-pre-split ]
+ %p2.1 = bitcast i32* %p2.1.in to i16*
+ br i1 %tobool19, label %while.end, label %while.cond
+
+while.end: ; preds = %while.cond
+ %inc20 = add nsw i32 %inc2060, 1
+ %tobool21 = icmp eq i32 %inc2060, 0
+ br i1 %tobool21, label %for.inc27.backedge, label %if.then22
+
+for.inc27.backedge: ; preds = %while.end, %if.then22
+ %inc28 = add nsw i32 %0, 1
+ store i32 %inc28, i32* @b, align 4, !tbaa !0
+ %tobool17 = icmp eq i32 %inc28, 0
+ br i1 %tobool17, label %for.inc27.if.end30.loopexit56_crit_edge, label %while.condthread-pre-split
+
+if.then22: ; preds = %while.end
+ %1 = load i16* %p2.1, align 2, !tbaa !3
+ %tobool23 = icmp eq i16 %1, 0
+ br i1 %tobool23, label %for.inc27.backedge, label %label.loopexit
+
+label.loopexit: ; preds = %if.then22
+ store i32 %inc20, i32* @a, align 4, !tbaa !0
+ %inc2858 = add nsw i32 %0, 1
+ store i32 %inc2858, i32* @b, align 4, !tbaa !0
+ %tobool1759 = icmp eq i32 %inc2858, 0
+ br i1 %tobool1759, label %if.end30, label %while.condthread-pre-split
+
+for.inc27.if.end30.loopexit56_crit_edge: ; preds = %for.inc27.backedge
+ store i32 %inc20, i32* @a, align 4, !tbaa !0
+ br label %if.end30
+
+if.end30: ; preds = %for.inc27.if.end30.loopexit56_crit_edge, %label.loopexit, %label.preheader, %for.inc
+ %i.0.load46 = phi i32 [ 0, %for.inc ], [ %i.0.load4669, %label.preheader ], [ %i.0.load4669, %label.loopexit ], [ %i.0.load4669, %for.inc27.if.end30.loopexit56_crit_edge ]
+ %pi.4 = phi i32* [ %i, %for.inc ], [ %pi.3.ph, %label.preheader ], [ %pi.3.ph, %label.loopexit ], [ %pi.3.ph, %for.inc27.if.end30.loopexit56_crit_edge ]
+ %2 = load i32* %pi.4, align 4, !tbaa !0
+ %tobool31 = icmp eq i32 %2, 0
+ br i1 %tobool31, label %for.inc34, label %label.preheader
+
+for.inc34: ; preds = %if.end30
+ %inc35 = add nsw i32 %i.0.load46, 1
+ store i32 %inc35, i32* %i, align 4
+ br label %for.cond
+
+for.end36: ; preds = %for.cond
+ store i32 1, i32* %i, align 4
+ %3 = load i32* @c, align 4, !tbaa !0
+ %tobool37 = icmp eq i32 %3, 0
+ br i1 %tobool37, label %label.preheader, label %land.rhs
+
+land.rhs: ; preds = %for.end36
+ store i32 0, i32* @a, align 4, !tbaa !0
+ br label %label.preheader
+
+label.preheader: ; preds = %for.end36, %if.end30, %land.rhs
+ %i.0.load4669 = phi i32 [ 1, %land.rhs ], [ %i.0.load46, %if.end30 ], [ 1, %for.end36 ]
+ %pi.3.ph = phi i32* [ %pi.0, %land.rhs ], [ %pi.4, %if.end30 ], [ %pi.0, %for.end36 ]
+ %4 = load i32* @b, align 4, !tbaa !0
+ %inc285863 = add nsw i32 %4, 1
+ store i32 %inc285863, i32* @b, align 4, !tbaa !0
+ %tobool175964 = icmp eq i32 %inc285863, 0
+ br i1 %tobool175964, label %if.end30, label %while.condthread-pre-split.lr.ph.lr.ph
+
+while.condthread-pre-split.lr.ph.lr.ph: ; preds = %label.preheader
+ %.pr50 = load i32* @d, align 4, !tbaa !0
+ %tobool19 = icmp eq i32 %.pr50, 0
+ %a.promoted.pre = load i32* @a, align 4, !tbaa !0
+ br label %while.condthread-pre-split
+}
+
+!0 = metadata !{metadata !"int", metadata !1}
+!1 = metadata !{metadata !"omnipotent char", metadata !2}
+!2 = metadata !{metadata !"Simple C/C++ TBAA"}
+!3 = metadata !{metadata !"short", metadata !1}