From 1239c9656bdcc0d86a2a4f89759acd5962e19ff6 Mon Sep 17 00:00:00 2001 From: Lang Hames Date: Tue, 27 Oct 2009 23:16:58 +0000 Subject: [PATCH] Fixed a bug in the coalescer where intervals were occasionally merged despite a real interference. This fixes rdar://problem/7157961. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85338 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/SimpleRegisterCoalescing.cpp | 19 +++++++++++++++++-- lib/CodeGen/SimpleRegisterCoalescing.h | 5 +++++ 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index f8784f60f5e..430df54081e 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -1861,6 +1861,21 @@ bool SimpleRegisterCoalescing::RangeIsDefinedByCopyFromReg(LiveInterval &li, return false; } + +/// ValueLiveAt - Return true if the LiveRange pointed to by the given +/// iterator, or any subsequent range with the same value number, +/// is live at the given point. +bool SimpleRegisterCoalescing::ValueLiveAt(LiveInterval::iterator LRItr, + LiveIndex defPoint) const { + for (const VNInfo *valno = LRItr->valno; LRItr->valno == valno; ++LRItr) { + if (LRItr->contains(defPoint)) + return true; + } + + return false; +} + + /// SimpleJoin - Attempt to joint the specified interval into this one. The /// caller of this method must guarantee that the RHS only contains a single /// value number and that the RHS is not defined by a copy from this @@ -1907,7 +1922,7 @@ bool SimpleRegisterCoalescing::SimpleJoin(LiveInterval &LHS, LiveInterval &RHS){ if (!RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg)) return false; // Nope, bail out. - if (LHSIt->contains(RHSIt->valno->def)) + if (ValueLiveAt(LHSIt, RHSIt->valno->def)) // Here is an interesting situation: // BB1: // vr1025 = copy vr1024 @@ -1945,7 +1960,7 @@ bool SimpleRegisterCoalescing::SimpleJoin(LiveInterval &LHS, LiveInterval &RHS){ // Otherwise, if this is a copy from the RHS, mark it as being merged // in. if (RangeIsDefinedByCopyFromReg(LHS, LHSIt, RHS.reg)) { - if (LHSIt->contains(RHSIt->valno->def)) + if (ValueLiveAt(LHSIt, RHSIt->valno->def)) // Here is an interesting situation: // BB1: // vr1025 = copy vr1024 diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h index 3ebe3a1f7de..a381ae78afe 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.h +++ b/lib/CodeGen/SimpleRegisterCoalescing.h @@ -201,6 +201,11 @@ namespace llvm { bool CanJoinInsertSubRegToPhysReg(unsigned DstReg, unsigned SrcReg, unsigned SubIdx, unsigned &RealDstReg); + /// ValueLiveAt - Return true if the LiveRange pointed to by the given + /// iterator, or any subsequent range with the same value number, + /// is live at the given point. + bool ValueLiveAt(LiveInterval::iterator LRItr, LiveIndex defPoint) const; + /// RangeIsDefinedByCopyFromReg - Return true if the specified live range of /// the specified live interval is defined by a copy from the specified /// register. -- 2.34.1