After r203553 overflow intrinsics and their non-intrinsic (normal)
instruction get hashed to the same value. This patch prevents PRE from
moving an instruction into a predecessor block, and trying to add a phi
node that gets two different types (the intrinsic result and the
non-intrinsic result), resulting in a failing assert.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203574 91177308-0d34-0410-b5e6-96231b3b80d8
When an overflow intrinsic is followed by a non-overflow instruction,
replace the latter with an extract. For example:
%sadd = tail call { i32, i1 } @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
%sadd3 = add i32 %a, %b
Here the add statement will be replaced by an extract.
When an overflow intrinsic follows a non-overflow instruction, a clone
of the intrinsic is inserted before the normal instruction, which makes
it the same as the previous case. Subsequent runs of GVN can then clean
up the duplicate instructions and insert the extract.
This fixes PR8817.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203553 91177308-0d34-0410-b5e6-96231b3b80d8
