Avoid excess precision issues that lead to generating host-compiler-specific code.
Switch lowering probably shouldn't be using FP for this. This resolves PR9581.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129199 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index f751bb7..8fb881b 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2019,9 +2019,13 @@
APInt Range = ComputeRange(LEnd, RBegin);
assert((Range - 2ULL).isNonNegative() &&
"Invalid case distance");
- double LDensity = (double)LSize.roundToDouble() /
+ // Use volatile double here to avoid excess precision issues on some hosts,
+ // e.g. that use 80-bit X87 registers.
+ volatile double LDensity =
+ (double)LSize.roundToDouble() /
(LEnd - First + 1ULL).roundToDouble();
- double RDensity = (double)RSize.roundToDouble() /
+ volatile double RDensity =
+ (double)RSize.roundToDouble() /
(Last - RBegin + 1ULL).roundToDouble();
double Metric = Range.logBase2()*(LDensity+RDensity);
// Should always split in some non-trivial place