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author | Quentin Colombet <qcolombet@apple.com> | 2014-04-11 21:39:44 +0000 |
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committer | Quentin Colombet <qcolombet@apple.com> | 2014-04-11 21:39:44 +0000 |
commit | 92a892e8f94533402b804d75080f9eec7da1e27b (patch) | |
tree | 1c1aa68d9bc62af320a209b3de9eb95e0384378e /lib/CodeGen/RegAllocGreedy.cpp | |
parent | 4aee5942c3e8f590ad71dce9588ce2f400628ba4 (diff) | |
download | llvm-92a892e8f94533402b804d75080f9eec7da1e27b.tar.gz llvm-92a892e8f94533402b804d75080f9eec7da1e27b.tar.bz2 llvm-92a892e8f94533402b804d75080f9eec7da1e27b.tar.xz |
[RegAllocGreedy][Last Chance Recoloring] Addition of
-fexhaustive-register-search option to allow an exhaustive search during last
chance recoloring.
This is related to PR18747
Patch by MAYUR PANDEY <mayur.p@samsung.com>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206072 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/RegAllocGreedy.cpp')
-rw-r--r-- | lib/CodeGen/RegAllocGreedy.cpp | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp index e65398f592..7a120e8802 100644 --- a/lib/CodeGen/RegAllocGreedy.cpp +++ b/lib/CodeGen/RegAllocGreedy.cpp @@ -73,6 +73,11 @@ static cl::opt<unsigned> LastChanceRecoloringMaxInterference( " interference at a time"), cl::init(8)); +static cl::opt<bool> +ExhaustiveSearch("fexhaustive-register-search", cl::NotHidden, + cl::desc("Exhaustive Search for registers bypassing the depth " + "and interference cutoffs of last chance recoloring")); + // FIXME: Find a good default for this flag and remove the flag. static cl::opt<unsigned> CSRFirstTimeCost("regalloc-csr-first-time-cost", @@ -1932,7 +1937,7 @@ RAGreedy::mayRecolorAllInterferences(unsigned PhysReg, LiveInterval &VirtReg, // If there is LastChanceRecoloringMaxInterference or more interferences, // chances are one would not be recolorable. if (Q.collectInterferingVRegs(LastChanceRecoloringMaxInterference) >= - LastChanceRecoloringMaxInterference) { + LastChanceRecoloringMaxInterference && !ExhaustiveSearch) { DEBUG(dbgs() << "Early abort: too many interferences.\n"); CutOffInfo |= CO_Interf; return false; @@ -2005,7 +2010,7 @@ unsigned RAGreedy::tryLastChanceRecoloring(LiveInterval &VirtReg, // We may want to reconsider that if we end up with a too large search space // for target with hundreds of registers. // Indeed, in that case we may want to cut the search space earlier. - if (Depth >= LastChanceRecoloringMaxDepth) { + if (Depth >= LastChanceRecoloringMaxDepth && !ExhaustiveSearch) { DEBUG(dbgs() << "Abort because max depth has been reached.\n"); CutOffInfo |= CO_Depth; return ~0u; @@ -2139,14 +2144,17 @@ unsigned RAGreedy::selectOrSplit(LiveInterval &VirtReg, if (Reg == ~0U && (CutOffInfo != CO_None)) { uint8_t CutOffEncountered = CutOffInfo & (CO_Depth | CO_Interf); if (CutOffEncountered == CO_Depth) - Ctx.emitError( - "register allocation failed: maximum depth for recoloring reached"); + Ctx.emitError("register allocation failed: maximum depth for recoloring " + "reached. Use -fexhaustive-register-search to skip " + "cutoffs"); else if (CutOffEncountered == CO_Interf) Ctx.emitError("register allocation failed: maximum interference for " - "recoloring reached"); + "recoloring reached. Use -fexhaustive-register-search " + "to skip cutoffs"); else if (CutOffEncountered == (CO_Depth | CO_Interf)) Ctx.emitError("register allocation failed: maximum interference and " - "depth for recoloring reached"); + "depth for recoloring reached. Use " + "-fexhaustive-register-search to skip cutoffs"); } return Reg; } |