From 0b23dc0cc8fb2967dc08574910536cc074863bcb Mon Sep 17 00:00:00 2001 From: Lang Hames Date: Tue, 9 Feb 2010 00:50:27 +0000 Subject: [PATCH] Fixed a bug in the PBQP allocator's findCoalesces method. Previously spill registers, whose def indexes are not defined, would sometimes be improperly marked as coalescable with conflicting registers. The new findCoalesces routine conservatively assumes that any register with at least one undefined def is not coalescable with any register it interferes with. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95636 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/RegAllocPBQP.cpp | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/lib/CodeGen/RegAllocPBQP.cpp b/lib/CodeGen/RegAllocPBQP.cpp index 74e155fd3fa..2701fafbf9b 100644 --- a/lib/CodeGen/RegAllocPBQP.cpp +++ b/lib/CodeGen/RegAllocPBQP.cpp @@ -411,16 +411,16 @@ PBQPRegAlloc::CoalesceMap PBQPRegAlloc::findCoalesces() { // We also need any physical regs to be allocable, coalescing with // a non-allocable register is invalid. if (srcRegIsPhysical) { - if (std::find(srcRegClass->allocation_order_begin(*mf), - srcRegClass->allocation_order_end(*mf), srcReg) == - srcRegClass->allocation_order_end(*mf)) + if (std::find(dstRegClass->allocation_order_begin(*mf), + dstRegClass->allocation_order_end(*mf), srcReg) == + dstRegClass->allocation_order_end(*mf)) continue; } if (dstRegIsPhysical) { - if (std::find(dstRegClass->allocation_order_begin(*mf), - dstRegClass->allocation_order_end(*mf), dstReg) == - dstRegClass->allocation_order_end(*mf)) + if (std::find(srcRegClass->allocation_order_begin(*mf), + srcRegClass->allocation_order_end(*mf), dstReg) == + srcRegClass->allocation_order_end(*mf)) continue; } @@ -442,6 +442,12 @@ PBQPRegAlloc::CoalesceMap PBQPRegAlloc::findCoalesces() { vniItr = srcLI->vni_begin(), vniEnd = srcLI->vni_end(); vniItr != vniEnd; ++vniItr) { + // If we find a poorly defined def we err on the side of caution. + if (!(*vniItr)->def.isValid()) { + badDef = true; + break; + } + // If we find a def that kills the coalescing opportunity then // record it and break from the loop. if (dstLI->liveAt((*vniItr)->def)) { @@ -463,6 +469,11 @@ PBQPRegAlloc::CoalesceMap PBQPRegAlloc::findCoalesces() { if ((*vniItr)->getCopy() == instr) continue; + if (!(*vniItr)->def.isValid()) { + badDef = true; + break; + } + if (srcLI->liveAt((*vniItr)->def)) { badDef = true; break; -- 2.34.1