Re: [PATCH v3] tree-optimization: Fold canonicalized vector min/max conditionals [PR98602]

On 7/22/2026 2:56 AM, Naveen wrote:
> The existing VEC_COND_EXPR min/max patterns require the comparison and result
> constants to be equal so they do not recognize this canonicalized form.
> Add patterns for the GE/LT forms produced from negative signed maximum
> expressions and for the LE/GT forms produced from positive signed or unsigned
> minimum expressions. Handle both normal and reversed conditional arms.
> The off-by-one check is performed elementwise so the transform is not
> restricted to uniform vector constants.
>
> This also handles non-uniform vector constants such as:
> X >= { -99, -98 } ? X : { -100, -99 }
> which can be folded to:
> MAX_EXPR <X, { -100, -99 }>
> when each comparison element is exactly one greater than the corresponding
> result element. Variable-length vector constants are handled when the two
> constants have matching VECTOR_CST encodings.
>
> gcc/ChangeLog:
> 	PR tree-optimization/98602
> 	* match.pd (vec_cond (cmp @0 VECTOR_CST@1) @0 VECTOR_CST@2):
> 	New simplification.
> 	(vec_cond (cmp @0 VECTOR_CST@1) VECTOR_CST@2 @0): Likewise.
> 	* tree.cc (record_uniform_integer_difference): New helper.
> 	(uniform_vector_difference_p): New function.
> 	* tree.h (uniform_vector_difference_p): Declare.
>
> gcc/testsuite/ChangeLog:
> 	PR tree-optimization/98602
> 	* g++.dg/tree-ssa/pr98602.C: New test.
> 	* g++.target/aarch64/sve/max_1.C: Remove fixed XFAILs.
> 	* g++.target/aarch64/sve/min_1.C: Likewise.
>
> Signed-off-by: Naveen <[email protected]>
OK.    I don't see testing information, so please make sure it's been 
bootstrapped and regression tested before installing.

Jeff