https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116024
--- Comment #5 from Artemiy Volkov <artemiy at synopsys dot com> --- Hi Andrew, thank you for the breakdown. For i1() (the case applicable to the initial bug report) something like this seems to fix the issue: diff --git a/gcc/match.pd b/gcc/match.pd index cf359b0ec0f..8ab6d47e278 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -8773,2 +8773,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) +/* Transform comparisons of the form C1 - X CMP C2 to X - C1 CMP -C2. */ +(for cmp (lt le gt ge eq ne) + rcmp (gt ge lt le eq ne) + (simplify + (cmp (minus INTEGER_CST@0 @1) INTEGER_CST@2) + (if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (@1))) + (rcmp (minus @1 @0) (negate @2))))) + /* Canonicalizations of BIT_FIELD_REFs. */ Would it make sense for this ticket to be assigned to me so I could refine and post the above patch as well as tackle i2() and i3() (should those be extracted to a separate PR or is it fine to fix all three under this PR)?
