instructions. I needed this for a quick experiment I was making, and
while I've no idea if that will ever get committed, I didn't want to
throw away the pattern match code and for anyone else to have to write
it again. I've added unittests to make sure this works correctly.
In fun news, this also uncovered the IRBuilder bug. Doh!
llvm-svn: 198541
basic block to hold instructions, and managing all of their lifetimes in
a fixture. This makes it easy to sink the expectations into the test
cases themselves which also makes things a bit more explicit and clearer
IMO.
llvm-svn: 198532
Add support for matching 'ordered' and 'unordered' floating point min/max
constructs.
In LLVM we can express min/max functions as a combination of compare and select.
We have support for matching such constructs for integers but not for floating
point. In floating point math there is no total order because of the presence of
'NaN'. Therefore, we have to be careful to preserve the original fcmp semantics
when interpreting floating point compare select combinations as a minimum or
maximum function. The resulting 'ordered/unordered' floating point maximum
function has to select the same value as the select/fcmp combination it is based
on.
ordered_max(x,y) = max(x,y) iff x and y are not NaN, y otherwise
unordered_max(x,y) = max(x,y) iff x and y are not NaN, x otherwise
ordered_min(x,y) = min(x,y) iff x and y are not NaN, y otherwise
unordered_min(x,y) = min(x,y) iff x and y are not NaN, x otherwise
This matches the behavior of the underlying select(fcmp(olt/ult/.., L, R), L, R)
construct.
Any code using this predicate has to preserve this semantics.
A follow-up patch will use this to implement floating point min/max reductions
in the vectorizer.
radar://13723044
llvm-svn: 181143
