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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-10-26 01:47:48 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-10-26 01:47:48 +0000 |
| commit | 794439183a29102c784484720c3d0b1960b297e6 (patch) | |
| tree | 0b31802fe6b2d5688f68527116c9758fc335ee49 | |
| parent | 73b5bb38650a1a1441fcf210c79f188d08990946 (diff) | |
Don't use floating point to do an integer's job.
This code makes different decisions when compiled into x87 instructions
because of different rounding behavior. That caused phase 2/3
miscompares on 32-bit Linux when the phase 1 compiler was built with gcc
(using x87), and the phase 2 compiler was built with clang (using SSE).
This fixes PR11200.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143006 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 24bd2cde78..4822da3df9 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -2034,14 +2034,17 @@ bool SelectionDAGBuilder::handleJTSwitchCase(CaseRec &CR, return false; APInt Range = ComputeRange(First, Last); - double Density = TSize.roundToDouble() / Range.roundToDouble(); - if (Density < 0.4) + // The density is TSize / Range. Require at least 40%. + // It should not be possible for IntTSize to saturate for sane code, but make + // sure we handle Range saturation correctly. + uint64_t IntRange = Range.getLimitedValue(UINT64_MAX/10); + uint64_t IntTSize = TSize.getLimitedValue(UINT64_MAX/10); + if (IntTSize * 10 < IntRange * 4) return false; DEBUG(dbgs() << "Lowering jump table\n" << "First entry: " << First << ". Last entry: " << Last << '\n' - << "Range: " << Range - << ". Size: " << TSize << ". Density: " << Density << "\n\n"); + << "Range: " << Range << ". Size: " << TSize << ".\n\n"); // Get the MachineFunction which holds the current MBB. This is used when // inserting any additional MBBs necessary to represent the switch. |