[llvm] [InstCombine] Teach tryFactorization to treat a disjoint Or like an Add. (PR #75691)

[Philip Reames via llvm-commits]

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@@ -1566,14 +1566,14 @@ define i32 @mul_no_common_bits_uses(i32 %p1, i32 %p2) {
   ret i32 %r
 }
 
-; negative test - probably not good to create an extra mul
+; TODO: is it good to create an extra mul?
 
 define i32 @mul_no_common_bits_const_op_uses(i32 %p) {
 ; CHECK-LABEL: @mul_no_common_bits_const_op_uses(
 ; CHECK-NEXT:    [[X:%.*]] = and i32 [[P:%.*]], 7
 ; CHECK-NEXT:    [[M:%.*]] = mul nuw nsw i32 [[X]], 24
 ; CHECK-NEXT:    call void @use(i32 [[M]])
-; CHECK-NEXT:    [[R:%.*]] = or disjoint i32 [[M]], [[X]]
+; CHECK-NEXT:    [[R:%.*]] = mul nuw nsw i32 [[X]], 25
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preames wrote:

I think I agree we should have the one use check for both add and or.  I'm entirely willing to let this go in so that we treat the disjoint or as an add, then fix the one use issue separately though.  They seem like orthogonal issues.  

https://github.com/llvm/llvm-project/pull/75691