Simplify (B * v + C) * D -> BD* v + CD when B,C,D are all INTEGER_CST.
Similar for (v + B) * C + D -> C * v + BCD.
Don't simplify it when there's overflow and overflow is UB for type v.
gcc/ChangeLog:
PR tree-optimization/53533
* match.pd: Simplify (B * v + C) * D -> BD * v + CD and
(v + B) * C + D -> C * v + BCD when B,C,D are all INTEGER_CST,
and there's no overflow or !TYPE_OVERFLOW_UNDEFINED.
gcc/testsuite/ChangeLog:
* gcc.target/i386/pr53533-1.c: New test.
* gcc.target/i386/pr53533-2.c: New test.
* gcc.target/i386/pr53533-3.c: New test.
* gcc.target/i386/pr53533-4.c: New test.
* gcc.target/i386/pr53533-5.c: New test.
* gcc.dg/vect/slp-11a.c: Adjust testcase.