On 9/15/26 2:06 PM, Andrea Pinski wrote:
This adds a simplification for `x+umax(x,1)` to `umax(x*2, 1)` when `x*2`
is known not to overflow. This shows up with std::vector::push_back
after the patch which adds `x+minmax(a,b)` simplification; it is also
a special case of that patch for `umax and 1`. This gives a small
code generation improvement with std::vector::push_back because we
trade an add after the umax with a shift beforehand.
Bootstrapped and tested on x86_64-linux-gnu.
Changes since v1:
* v2: rebase
PR tree-optimization/127103
gcc/ChangeLog:
* match.pd (`x+umax(x,1)`): New pattern.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/max1-plus-1.c: New test.
Signed-off-by: Andrea Pinski <[email protected]>
This series is OK. While this looks more like canonicalization or
otherwise changing the IL to make other optimizations easier without
reducing the expression evaluation count, I can't make a case that
either form is inherently better than the other. So given this allows
you to zap infeasible paths in patch#2 of the series, it seems like a
pragmatic choice.
Jeff
