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b1b97833ae
Patch by Michael Ilseman!
This fixes SimplifyCFGOpt::FoldValueComparisonIntoPredecessors to preserve metata when folding conditional branches into switches.
void foo(int x) {
if (x == 0)
bar(1);
else if (__builtin_expect(x == 10, 1))
bar(2);
else if (x == 20)
bar(3);
}
CFG:
B0
| \
| X0
B10
| \
| X10
B20
| \
E X20
Merge B0-B10:
w(B0-X0) = w(B0-X0)*sum-weights(B10) = w(B0-X0) * (w(B10-X10) + w(B10-B20))
w(B0-X10) = w(B0-B10) * w(B10-X10)
w(B0-B20) = w(B0-B10) * w(B10-B20)
B0 __
| \ \
| X10 X0
B20
| \
E X20
Merge B0-B20:
w(B0-X0) = w(B0-X0) * sum-weights(B20) = w(B0-X0) * (w(B20-E) + w(B20-X20))
w(B0-X10) = w(B0-X10) * sum-weights(B20) = ...
w(B0-X20) = w(B0-B20) * w(B20-X20)
w(B0-E) = w(B0-B20) * w(B20-E)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162868 91177308-0d34-0410-b5e6-96231b3b80d8